1
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Gallardo R, Weigand M, Schultheiss K, Kakay A, Mattheis R, Raabe J, Schütz G, Deac A, Lindner J, Wintz S. Coherent Magnons with Giant Nonreciprocity at Nanoscale Wavelengths. ACS Nano 2024. [PMID: 38314709 PMCID: PMC10883124 DOI: 10.1021/acsnano.3c08390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2024]
Abstract
Nonreciprocal wave propagation arises in systems with broken time-reversal symmetry and is key to the functionality of devices, such as isolators or circulators, in microwave, photonic, and acoustic applications. In magnetic systems, collective wave excitations known as magnon quasiparticles have so far yielded moderate nonreciprocities, mainly observed by means of incoherent thermal magnon spectra, while their occurrence as coherent spin waves (magnon ensembles with identical phase) is yet to be demonstrated. Here, we report the direct observation of strongly nonreciprocal propagating coherent spin waves in a patterned element of a ferromagnetic bilayer stack with antiparallel magnetic orientations. We use time-resolved scanning transmission X-ray microscopy (TR-STXM) to directly image the layer-collective dynamics of spin waves with wavelengths ranging from 5 μm down to 100 nm emergent at frequencies between 500 MHz and 5 GHz. The experimentally observed nonreciprocity factor of these counter-propagating waves is greater than 10 with respect to both group velocities and specific wavelengths. Our experimental findings are supported by the results from an analytic theory, and their peculiarities are further discussed in terms of caustic spin-wave focusing.
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Affiliation(s)
- Rodolfo Gallardo
- Universidad Técnica Federico Santa María, 2390123 Valparaíso, Chile
| | | | - Katrin Schultheiss
- Helmholtz-Zentrum Dresden-Rossendorf, Insitute of Ion Beam Physics and Materials Research, 01328 Dresden, Germany
| | - Attila Kakay
- Helmholtz-Zentrum Dresden-Rossendorf, Insitute of Ion Beam Physics and Materials Research, 01328 Dresden, Germany
| | - Roland Mattheis
- Leibniz Institut für Photonische Technologien, 07745 Jena, Germany
| | - Jörg Raabe
- Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Gisela Schütz
- Max-Planck-Institut für Intelligente Systeme, 70569 Stuttgart, Germany
| | - Alina Deac
- Helmholtz-Zentrum Dresden-Rossendorf, Dresden High Magnetic Field Laboratory, 01328 Dresden, Germany
| | - Jürgen Lindner
- Helmholtz-Zentrum Dresden-Rossendorf, Insitute of Ion Beam Physics and Materials Research, 01328 Dresden, Germany
| | - Sebastian Wintz
- Helmholtz-Zentrum Berlin, 12489 Berlin, Germany
- Max-Planck-Institut für Intelligente Systeme, 70569 Stuttgart, Germany
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2
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Schulz F, Litzius K, Powalla L, Birch MT, Gallardo RA, Satheesh S, Weigand M, Scholz T, Lotsch BV, Schütz G, Burghard M, Wintz S. Direct Observation of Propagating Spin Waves in the 2D van der Waals Ferromagnet Fe 5GeTe 2. Nano Lett 2023; 23:10126-10131. [PMID: 37955345 PMCID: PMC10683057 DOI: 10.1021/acs.nanolett.3c02212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 11/01/2023] [Accepted: 11/03/2023] [Indexed: 11/14/2023]
Abstract
Magnetism in reduced dimensionalities is of great fundamental interest while also providing perspectives for applications of materials with novel functionalities. In particular, spin dynamics in two dimensions (2D) have become a focus of recent research. Here, we report the observation of coherent propagating spin-wave dynamics in a ∼30 nm thick flake of 2D van der Waals ferromagnet Fe5GeTe2 using X-ray microscopy. Both phase and amplitude information were obtained by direct imaging below TC for frequencies from 2.77 to 3.84 GHz, and the corresponding spin-wave wavelengths were measured to be between 1.5 and 0.5 μm. Thus, parts of the magnonic dispersion relation were determined despite a relatively high magnetic damping of the material. Numerically solving an analytic multilayer model allowed us to corroborate the experimental dispersion relation and predict the influence of changes in the saturation magnetization or interlayer coupling, which could be exploited in future applications by temperature control or stacking of 2D-heterostructures.
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Affiliation(s)
- Frank Schulz
- Max
Planck Institute for Intelligent Systems, Heisenbergstrasse 3, D-70569 Stuttgart, Germany
| | - Kai Litzius
- Max
Planck Institute for Intelligent Systems, Heisenbergstrasse 3, D-70569 Stuttgart, Germany
- Universität
Augsburg, D-86159 Augsburg, Germany
| | - Lukas Powalla
- Max
Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - Max T. Birch
- Max
Planck Institute for Intelligent Systems, Heisenbergstrasse 3, D-70569 Stuttgart, Germany
- RIKEN
Center for Emergent Matter Science, JP-351-0198 Wako, Japan
| | - Rodolfo A. Gallardo
- Universidad
Técnica Federico Santa María, Avenida España 1680, 2390123 Valparaiso, Chile
| | - Sayooj Satheesh
- Max
Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - Markus Weigand
- Max
Planck Institute for Intelligent Systems, Heisenbergstrasse 3, D-70569 Stuttgart, Germany
- Helmholtz-Zentrum
Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109 Berlin, Germany
| | - Tanja Scholz
- Max
Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - Bettina V. Lotsch
- Max
Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - Gisela Schütz
- Max
Planck Institute for Intelligent Systems, Heisenbergstrasse 3, D-70569 Stuttgart, Germany
| | - Marko Burghard
- Max
Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - Sebastian Wintz
- Max
Planck Institute for Intelligent Systems, Heisenbergstrasse 3, D-70569 Stuttgart, Germany
- Helmholtz-Zentrum
Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109 Berlin, Germany
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3
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Ilse SE, Schütz G, Goering E. Voltage X-Ray Reflectometry: A Method to Study Electric-Field-Induced Changes in Interfacial Electronic Structures. Phys Rev Lett 2023; 131:036201. [PMID: 37540862 DOI: 10.1103/physrevlett.131.036201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 04/26/2023] [Accepted: 06/07/2023] [Indexed: 08/06/2023]
Abstract
Magnetic multilayers with a separating insulating layer are used in a multitude of functional devices. Controlling the magnetic properties of such devices with an electric field has the potential to vastly enhance their performance. Nevertheless, experimental methods to study the origin of electric-field-induced effects on buried interfaces remain elusive. By using element selective x-ray resonant magnetic reflectometry we are able to gain access to changes in the electronic structure of interfacial atoms caused by an electric field. With this method it is possible to probe interfacial states at the Fermi energy. In a multilayer stack with a Ni/SiO_{2} interface, we find that the electric field slightly shifts the Ni L_{3}-edge in energy, which indicates a change of the oxidation state of interfacial Ni atoms. Further analysis of the strength of the effect reveals that only about 30% of the electrons moved by the electric field end up in interfacial Ni states.
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Affiliation(s)
- Sven Erik Ilse
- Max-Planck-Institute for Solid State Research, D-70569 Stuttgart, Germany
| | - Gisela Schütz
- Max-Planck-Institute for Intelligent Systems, D-70569 Stuttgart, Germany
| | - Eberhard Goering
- Max-Planck-Institute for Solid State Research, D-70569 Stuttgart, Germany
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4
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Soltan S, Macke S, Ilse SE, Pennycook T, Zhang ZL, Christiani G, Benckiser E, Schütz G, Goering E. Ferromagnetic order controlled by the magnetic interface of LaNiO 3/La 2/3Ca 1/3MnO 3 superlattices. Sci Rep 2023; 13:3847. [PMID: 36890187 PMCID: PMC9995495 DOI: 10.1038/s41598-023-30814-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 03/01/2023] [Indexed: 03/10/2023] Open
Abstract
Interface engineering in complex oxide superlattices is a growing field, enabling manipulation of the exceptional properties of these materials, and also providing access to new phases and emergent physical phenomena. Here we demonstrate how interfacial interactions can induce a complex charge and spin structure in a bulk paramagnetic material. We investigate a superlattice (SLs) consisting of paramagnetic LaNiO3 (LNO) and highly spin-polarized ferromagnetic La2/3Ca1/3MnO3 (LCMO), grown on SrTiO3 (001) substrate. We observed emerging magnetism in LNO through an exchange bias mechanism at the interfaces in X-ray resonant magnetic reflectivity. We find non-symmetric interface induced magnetization profiles in LNO and LCMO which we relate to a periodic complex charge and spin superstructure. High resolution scanning transmission electron microscopy images reveal that the upper and lower interfaces exhibit no significant structural variations. The different long range magnetic order emerging in LNO layers demonstrates the enormous potential of interfacial reconstruction as a tool for tailored electronic properties.
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Affiliation(s)
- S Soltan
- Physics Department, Faculty of Science, Helwan University, Helwan, Cairo, 11798, Egypt. .,Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569, Stuttgart, Germany. .,Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany.
| | - S Macke
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany
| | - S E Ilse
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569, Stuttgart, Germany
| | - T Pennycook
- EMAT, University of Antwerp Campus Groenenborger, 2020, Antwerp, Belgium.,Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090, Vienna, Austria
| | - Z L Zhang
- Erich-Schmid-Institute of Materials Science, Austrian Academy of Sciences, Jahnstraße 12, 8700, Leoben, Austria
| | - G Christiani
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany
| | - E Benckiser
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany
| | - G Schütz
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569, Stuttgart, Germany
| | - E Goering
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569, Stuttgart, Germany.
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5
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Gerlinger K, Pfau B, Hennecke M, Kern LM, Will I, Noll T, Weigand M, Gräfe J, Träger N, Schneider M, Günther CM, Engel D, Schütz G, Eisebitt S. Pump-probe x-ray microscopy of photo-induced magnetization dynamics at MHz repetition rates. Struct Dyn 2023; 10:024301. [PMID: 36970496 PMCID: PMC10038236 DOI: 10.1063/4.0000167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 02/16/2023] [Indexed: 06/18/2023]
Abstract
We present time-resolved scanning x-ray microscopy measurements with picosecond photo-excitation via a tailored infrared pump laser at a scanning transmission x-ray microscope. Specifically, we image the laser-induced demagnetization and remagnetization of thin ferrimagnetic GdFe films proceeding on a few nanoseconds timescale. Controlling the heat load on the sample via additional reflector and heatsink layers allows us to conduct destruction-free measurements at a repetition rate of 50 MHz. Near-field enhancement of the photo-excitation and controlled annealing effects lead to laterally heterogeneous magnetization dynamics which we trace with 30 nm spatial resolution. Our work opens new opportunities to study photo-induced dynamics on the nanometer scale, with access to picosecond to nanosecond time scales, which is of technological relevance, especially in the field of magnetism.
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Affiliation(s)
- Kathinka Gerlinger
- Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, 12489 Berlin, Germany
| | - Bastian Pfau
- Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, 12489 Berlin, Germany
| | - Martin Hennecke
- Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, 12489 Berlin, Germany
| | - Lisa-Marie Kern
- Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, 12489 Berlin, Germany
| | - Ingo Will
- Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, 12489 Berlin, Germany
| | - Tino Noll
- Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, 12489 Berlin, Germany
| | - Markus Weigand
- Helmholtz-Zentrum Berlin für Materialien und Energie, 12489 Berlin, Germany
| | - Joachim Gräfe
- Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - Nick Träger
- Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - Michael Schneider
- Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, 12489 Berlin, Germany
| | - Christian M. Günther
- Technische Universität Berlin, Zentraleinrichtung Elektronenmikroskopie (ZELMI), 10623 Berlin, Germany
| | - Dieter Engel
- Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, 12489 Berlin, Germany
| | - Gisela Schütz
- Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
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6
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Powalla L, Birch MT, Litzius K, Wintz S, Yasin FS, Turnbull LA, Schulz F, Mayoh DA, Balakrishnan G, Weigand M, Yu X, Kern K, Schütz G, Burghard M. Seeding and Emergence of Composite Skyrmions in a van der Waals Magnet. Adv Mater 2023; 35:e2208930. [PMID: 36637996 DOI: 10.1002/adma.202208930] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 12/14/2022] [Indexed: 06/17/2023]
Abstract
Topological charge plays a significant role in a range of physical systems. In particular, observations of real-space topological objects in magnetic materials have been largely limited to skyrmions - states with a unitary topological charge. Recently, more exotic states with varying topology, such as antiskyrmions, merons, or bimerons and 3D states such as skyrmion strings, chiral bobbers, and hopfions, have been experimentally reported. Along these lines, the realization of states with higher-order topology has the potential to open new avenues of research in topological magnetism and its spintronic applications. Here, real-space imaging of such spin textures, including skyrmion, skyrmionium, skyrmion bag, and skyrmion sack states, observed in exfoliated flakes of the van der Waals magnet Fe3-x GeTe2 (FGT) is reported. These composite skyrmions may emerge from seeded, loop-like states condensed into the stripe domain structure, demonstrating the possibility to realize spin textures with arbitrary integer topological charge within exfoliated flakes of 2D magnets. The general nature of the formation mechanism motivates the search for composite skyrmion states in both well-known and new magnetic materials, which may yet reveal an even richer spectrum of higher-order topological objects.
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Affiliation(s)
- Lukas Powalla
- Max Planck Institute for Solid State Research, 70569, Stuttgart, Germany
| | - Max T Birch
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
| | - Kai Litzius
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - Sebastian Wintz
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - Fehmi S Yasin
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
| | - Luke A Turnbull
- Department of Physics, Durham University, Durham, DH1 3LE, UK
| | - Frank Schulz
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - Daniel A Mayoh
- Department of Physics, University of Warwick, Coventry, CV4 7AL, UK
| | | | - Markus Weigand
- Institute Nanospectroscopy, Helmholtz-Zentrum Berlin, 12489, Berlin, Germany
| | - Xiuzhen Yu
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
| | - Klaus Kern
- Max Planck Institute for Solid State Research, 70569, Stuttgart, Germany
- Institut de Physique, École Polytechnique Fédérale de Lausanne, Lausanne, 1015, Switzerland
| | - Gisela Schütz
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - Marko Burghard
- Max Planck Institute for Solid State Research, 70569, Stuttgart, Germany
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7
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Powalla L, Birch MT, Litzius K, Wintz S, Schulz F, Weigand M, Scholz T, Lotsch BV, Kern K, Schütz G, Burghard M. Single Skyrmion Generation via a Vertical Nanocontact in a 2D Magnet-Based Heterostructure. Nano Lett 2022; 22:9236-9243. [PMID: 36400013 PMCID: PMC9756335 DOI: 10.1021/acs.nanolett.2c01944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 11/07/2022] [Indexed: 06/16/2023]
Abstract
Skyrmions have been well studied in chiral magnets and magnetic thin films due to their potential application in practical devices. Recently, monochiral skyrmions have been observed in two-dimensional van der Waals magnets. Their atomically flat surfaces and capability to be stacked into heterostructures offer new prospects for skyrmion applications. However, the controlled local nucleation of skyrmions within these materials has yet to be realized. Here, we utilize real-space X-ray microscopy to investigate a heterostructure composed of the 2D ferromagnet Fe3GeTe2 (FGT), an insulating hexagonal boron nitride layer, and a graphite top electrode. Upon a stepwise increase of the voltage applied between the graphite and FGT, a vertically conducting pathway can be formed. This nanocontact allows the tunable creation of individual skyrmions via single nanosecond pulses of low current density. Furthermore, time-resolved magnetic imaging highlights the stability of the nanocontact, while our micromagnetic simulations reproduce the observed skyrmion nucleation process.
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Affiliation(s)
- Lukas Powalla
- Max
Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569Stuttgart, Germany
| | - Max T. Birch
- Max
Planck Institute for Intelligent Systems, Heisenbergstrasse 3, D-70569Stuttgart, Germany
| | - Kai Litzius
- Max
Planck Institute for Intelligent Systems, Heisenbergstrasse 3, D-70569Stuttgart, Germany
| | - Sebastian Wintz
- Max
Planck Institute for Intelligent Systems, Heisenbergstrasse 3, D-70569Stuttgart, Germany
- Helmholtz-Zentrum
Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109Berlin, Germany
| | - Frank Schulz
- Max
Planck Institute for Intelligent Systems, Heisenbergstrasse 3, D-70569Stuttgart, Germany
| | - Markus Weigand
- Max
Planck Institute for Intelligent Systems, Heisenbergstrasse 3, D-70569Stuttgart, Germany
- Helmholtz-Zentrum
Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109Berlin, Germany
| | - Tanja Scholz
- Max
Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569Stuttgart, Germany
| | - Bettina V. Lotsch
- Max
Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569Stuttgart, Germany
- University
of Munich (LMU), Butenandtstraße 5-13 (Haus D), 81377München, Germany
| | - Klaus Kern
- Max
Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569Stuttgart, Germany
- Institute
de Physique, École Polytechnique
Fédérale de Lausanne, CH-1015Lausanne, Switzerland
| | - Gisela Schütz
- Max
Planck Institute for Intelligent Systems, Heisenbergstrasse 3, D-70569Stuttgart, Germany
| | - Marko Burghard
- Max
Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569Stuttgart, Germany
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8
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Balderas-Xicohténcatl R, Lin HH, Lurz C, Daemen L, Cheng Y, Cychosz Struckhoff K, Guillet-Nicolas R, Schütz G, Heine T, Ramirez-Cuesta AJ, Thommes M, Hirscher M. Formation of a super-dense hydrogen monolayer on mesoporous silica. Nat Chem 2022; 14:1319-1324. [PMID: 36038772 DOI: 10.1038/s41557-022-01019-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 07/06/2022] [Indexed: 11/09/2022]
Abstract
Adsorption on various adsorbents of hydrogen and helium at temperatures close to their boiling points shows, in some cases, unusually high monolayer capacities. The microscopic nature of these adsorbate phases at low temperatures has, however, remained challenging to characterize. Here, using high-resolution cryo-adsorption studies together with characterization by inelastic neutron scattering vibration spectroscopy, we show that, near its boiling point (~20 K), H2 adsorbed on a well-ordered mesoporous silica forms a two-dimensional monolayer with a density more than twice that of bulk-solid H2, rather than a bilayer. Theoretical studies, based on thorough first-principles calculations, rationalize the formation of such a super-dense phase. The strong compression of the hydrogen surface layer is due to the excess of surface-hydrogen attraction over intermolecular hydrogen repulsion. Use of this super-dense hydrogen monolayer on an adsorbent might be a feasible option for the storage of hydrogen near its boiling point, compared with adsorption at 77 K.
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Affiliation(s)
- Rafael Balderas-Xicohténcatl
- Max Planck Institute for Intelligent Systems, Stuttgart, Germany. .,Neutron Scattering Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, TN, USA.
| | - Hung-Hsuan Lin
- Helmholtz Center Dresden-Rossendorf, Institute of Resource Ecology, Leipzig Branch, Leipzig, Germany
| | - Christian Lurz
- Helmholtz Center Dresden-Rossendorf, Institute of Resource Ecology, Leipzig Branch, Leipzig, Germany
| | - Luke Daemen
- Neutron Scattering Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Yongqiang Cheng
- Neutron Scattering Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | | | - Remy Guillet-Nicolas
- Laboratoire Catalyse et Spectrochemiem, Normandie University, ENSICAEN, CNRS, Caen, France
| | - Gisela Schütz
- Max Planck Institute for Intelligent Systems, Stuttgart, Germany
| | - Thomas Heine
- Helmholtz Center Dresden-Rossendorf, Institute of Resource Ecology, Leipzig Branch, Leipzig, Germany.,School of Mathematics and Science, TU Dresden, Dresden, Germany.,Department of Chemistry, Yonsei University, Seodaemun-gu, Seoul, Republic of Korea
| | - Anibal J Ramirez-Cuesta
- Neutron Scattering Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Matthias Thommes
- Institute of Separation Science and Technology, Department of Chemical and Biological Engineering (CBI), Friedrich-Alexander University, Erlangen, Germany
| | - Michael Hirscher
- Max Planck Institute for Intelligent Systems, Stuttgart, Germany.
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9
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Birch MT, Cortés-Ortuño D, Litzius K, Wintz S, Schulz F, Weigand M, Štefančič A, Mayoh DA, Balakrishnan G, Hatton PD, Schütz G. Toggle-like current-induced Bloch point dynamics of 3D skyrmion strings in a room temperature nanowire. Nat Commun 2022; 13:3630. [PMID: 35750676 PMCID: PMC9232487 DOI: 10.1038/s41467-022-31335-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 06/15/2022] [Indexed: 11/09/2022] Open
Abstract
Research into practical applications of magnetic skyrmions, nanoscale solitons with interesting topological and transport properties, has traditionally focused on two dimensional (2D) thin-film systems. However, the recent observation of novel three dimensional (3D) skyrmion-like structures, such as hopfions, skyrmion strings (SkS), skyrmion bundles, and skyrmion braids, motivates the investigation of new designs, aiming to exploit the third spatial dimension for more compact and higher performance spintronic devices in 3D or curvilinear geometries. A crucial requirement of such device schemes is the control of the 3D magnetic structures via charge or spin currents, which has yet to be experimentally observed. In this work, we utilise real-space imaging to investigate the dynamics of a 3D SkS within a nanowire of Co8Zn9Mn3 at room temperature. Utilising single current pulses, we demonstrate current-induced nucleation of a single SkS, and a toggle-like positional switching of an individual Bloch point at the end of a SkS. The observations highlight the possibility to locally manipulate 3D topological spin textures, opening up a range of design concepts for future 3D spintronic devices. In three dimensional systems with broken bulk inversion symmetry, skyrmions can form extended string-like structures. Here, Birch et al use scanning transmission x-ray microscopy to demonstrate the current induced generation and motion of these three dimensional skyrmion strings.
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Affiliation(s)
- M T Birch
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany.
| | - D Cortés-Ortuño
- Department of Earth Sciences, Utrecht University, 3584, CB, Utrecht, The Netherlands.
| | - K Litzius
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - S Wintz
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany.,Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, 12489, Berlin, Germany
| | - F Schulz
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - M Weigand
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, 12489, Berlin, Germany
| | - A Štefančič
- Department of Physics, University of Warwick, Coventry, CV4 7AL, UK.,Electrochemistry Laboratory, Paul Scherrer Institut, CH-5232, Villigen, PSI, Switzerland
| | - D A Mayoh
- Department of Physics, University of Warwick, Coventry, CV4 7AL, UK
| | - G Balakrishnan
- Department of Physics, University of Warwick, Coventry, CV4 7AL, UK
| | - P D Hatton
- Department of Physics, Durham University, Durham, DH1 3LE, UK
| | - G Schütz
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
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10
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Birch MT, Cortés-Ortuño D, Litzius K, Wintz S, Schulz F, Weigand M, Štefančič A, Mayoh DA, Balakrishnan G, Hatton PD, Schütz G. Toggle-like current-induced Bloch point dynamics of 3D skyrmion strings in a room temperature nanowire. Nat Commun 2022; 13:3630. [PMID: 35750676 DOI: 10.21203/rs.3.rs-1235546/v1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 06/15/2022] [Indexed: 05/23/2023] Open
Abstract
Research into practical applications of magnetic skyrmions, nanoscale solitons with interesting topological and transport properties, has traditionally focused on two dimensional (2D) thin-film systems. However, the recent observation of novel three dimensional (3D) skyrmion-like structures, such as hopfions, skyrmion strings (SkS), skyrmion bundles, and skyrmion braids, motivates the investigation of new designs, aiming to exploit the third spatial dimension for more compact and higher performance spintronic devices in 3D or curvilinear geometries. A crucial requirement of such device schemes is the control of the 3D magnetic structures via charge or spin currents, which has yet to be experimentally observed. In this work, we utilise real-space imaging to investigate the dynamics of a 3D SkS within a nanowire of Co8Zn9Mn3 at room temperature. Utilising single current pulses, we demonstrate current-induced nucleation of a single SkS, and a toggle-like positional switching of an individual Bloch point at the end of a SkS. The observations highlight the possibility to locally manipulate 3D topological spin textures, opening up a range of design concepts for future 3D spintronic devices.
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Affiliation(s)
- M T Birch
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany.
| | - D Cortés-Ortuño
- Department of Earth Sciences, Utrecht University, 3584, CB, Utrecht, The Netherlands.
| | - K Litzius
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - S Wintz
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, 12489, Berlin, Germany
| | - F Schulz
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - M Weigand
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, 12489, Berlin, Germany
| | - A Štefančič
- Department of Physics, University of Warwick, Coventry, CV4 7AL, UK
- Electrochemistry Laboratory, Paul Scherrer Institut, CH-5232, Villigen, PSI, Switzerland
| | - D A Mayoh
- Department of Physics, University of Warwick, Coventry, CV4 7AL, UK
| | - G Balakrishnan
- Department of Physics, University of Warwick, Coventry, CV4 7AL, UK
| | - P D Hatton
- Department of Physics, Durham University, Durham, DH1 3LE, UK
| | - G Schütz
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
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11
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Birch MT, Powalla L, Wintz S, Hovorka O, Litzius K, Loudon JC, Turnbull LA, Nehruji V, Son K, Bubeck C, Rauch TG, Weigand M, Goering E, Burghard M, Schütz G. History-dependent domain and skyrmion formation in 2D van der Waals magnet Fe 3GeTe 2. Nat Commun 2022; 13:3035. [PMID: 35641499 PMCID: PMC9156682 DOI: 10.1038/s41467-022-30740-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 05/16/2022] [Indexed: 11/16/2022] Open
Abstract
The discovery of two-dimensional magnets has initiated a new field of research, exploring both fundamental low-dimensional magnetism, and prospective spintronic applications. Recently, observations of magnetic skyrmions in the 2D ferromagnet Fe3GeTe2 (FGT) have been reported, introducing further application possibilities. However, controlling the exhibited magnetic state requires systematic knowledge of the history-dependence of the spin textures, which remains largely unexplored in 2D magnets. In this work, we utilise real-space imaging, and complementary simulations, to determine and explain the thickness-dependent magnetic phase diagrams of an exfoliated FGT flake, revealing a complex, history-dependent emergence of the uniformly magnetised, stripe domain and skyrmion states. The results show that the interplay of the dominant dipolar interaction and strongly temperature dependent out-of-plane anisotropy energy terms enables the selective stabilisation of all three states at zero field, and at a single temperature, while the Dzyaloshinksii-Moriya interaction must be present to realise the observed Néel-type domain walls. The findings open perspectives for 2D devices incorporating topological spin textures. Fe3GeTe2, known as FGT, is a van der Waals magnetic material that was recently shown to host magnetic skyrmions. Here, Birch et al using both X-ray and electron microscopy to study the stability of skyrmions in FGT, revealing how the sample history can influence skyrmion formation
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Affiliation(s)
- M T Birch
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany.
| | - L Powalla
- Max Planck Institute for Solid State Research, 70569, Stuttgart, Germany.
| | - S Wintz
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - O Hovorka
- Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - K Litzius
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - J C Loudon
- Department of Materials Science and Metallurgy, University of Cambridge, Cambridge, CB3 0FS, UK
| | - L A Turnbull
- Department of Physics, Durham University, Durham, DH1 3LE, UK
| | - V Nehruji
- Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - K Son
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany.,Department of Physics Education, Kongju National University, Gongju, 32588, South Korea
| | - C Bubeck
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - T G Rauch
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Institut Nanospektroskopie, 12489, Berlin, Germany
| | - M Weigand
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Institut Nanospektroskopie, 12489, Berlin, Germany
| | - E Goering
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - M Burghard
- Max Planck Institute for Solid State Research, 70569, Stuttgart, Germany
| | - G Schütz
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
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12
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Ahlberg M, Chung S, Jiang S, Frisk A, Khademi M, Khymyn R, Awad AA, Le QT, Mazraati H, Mohseni M, Weigand M, Bykova I, Groß F, Goering E, Schütz G, Gräfe J, Åkerman J. Freezing and thawing magnetic droplet solitons. Nat Commun 2022; 13:2462. [PMID: 35513369 PMCID: PMC9072373 DOI: 10.1038/s41467-022-30055-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 04/14/2022] [Indexed: 11/18/2022] Open
Abstract
Magnetic droplets are non-topological magnetodynamical solitons displaying a wide range of complex dynamic phenomena with potential for microwave signal generation. Bubbles, on the other hand, are internally static cylindrical magnetic domains, stabilized by external fields and magnetostatic interactions. In its original theory, the droplet was described as an imminently collapsing bubble stabilized by spin transfer torque and, in its zero-frequency limit, as equivalent to a bubble. Without nanoscale lateral confinement, pinning, or an external applied field, such a nanobubble is unstable, and should collapse. Here, we show that we can freeze dynamic droplets into static nanobubbles by decreasing the magnetic field. While the bubble has virtually the same resistance as the droplet, all signs of low-frequency microwave noise disappear. The transition is fully reversible and the bubble can be thawed back into a droplet if the magnetic field is increased under current. Whereas the droplet collapses without a sustaining current, the bubble is highly stable and remains intact for days without external drive. Electrical measurements are complemented by direct observation using scanning transmission x-ray microscopy, which corroborates the analysis and confirms that the bubble is stabilized by pinning. Magnetic droplets are a type of non-topological magnetic soliton, which are stabilised and sustained by spin-transfer torques for instance. Without this, they would collapse. Here Ahlberg et al show that by decreasing the applied magnetic field, droplets can be frozen, forming a static nanobubble
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Affiliation(s)
- Martina Ahlberg
- Department of Physics, University of Gothenburg, 412 96, Gothenburg, Sweden
| | - Sunjae Chung
- Department of Physics, University of Gothenburg, 412 96, Gothenburg, Sweden. .,Department of Physics Education, Korea National University of Education, Cheongju, 28173, Korea.
| | - Sheng Jiang
- Department of Physics, University of Gothenburg, 412 96, Gothenburg, Sweden.,School of Microelectronics, Northwestern Polytechnical University, 710072, Xi'an, China.,Department of Applied Physics, School of Engineering Sciences, KTH Royal Institute of Technology, 100 44, Stockholm, Sweden
| | - Andreas Frisk
- Department of Physics, University of Gothenburg, 412 96, Gothenburg, Sweden
| | - Maha Khademi
- Department of Physics, Shahid Beheshti University, Evin, 1983969411, Tehran, Iran
| | - Roman Khymyn
- Department of Physics, University of Gothenburg, 412 96, Gothenburg, Sweden
| | - Ahmad A Awad
- Department of Physics, University of Gothenburg, 412 96, Gothenburg, Sweden
| | - Q Tuan Le
- Department of Physics, University of Gothenburg, 412 96, Gothenburg, Sweden.,Department of Applied Physics, School of Engineering Sciences, KTH Royal Institute of Technology, 100 44, Stockholm, Sweden
| | - Hamid Mazraati
- Department of Applied Physics, School of Engineering Sciences, KTH Royal Institute of Technology, 100 44, Stockholm, Sweden.,NanOsc AB, 164 40, Kista, Sweden
| | - Majid Mohseni
- Department of Applied Physics, School of Engineering Sciences, KTH Royal Institute of Technology, 100 44, Stockholm, Sweden.,Department of Physics, Shahid Beheshti University, Evin, 1983969411, Tehran, Iran
| | - Markus Weigand
- Max Planck Institute for Intelligent Systems, Stuttgart, Germany
| | - Iuliia Bykova
- Max Planck Institute for Intelligent Systems, Stuttgart, Germany
| | - Felix Groß
- Max Planck Institute for Intelligent Systems, Stuttgart, Germany
| | - Eberhard Goering
- Max Planck Institute for Intelligent Systems, Stuttgart, Germany
| | - Gisela Schütz
- Max Planck Institute for Intelligent Systems, Stuttgart, Germany
| | - Joachim Gräfe
- Max Planck Institute for Intelligent Systems, Stuttgart, Germany
| | - Johan Åkerman
- Department of Physics, University of Gothenburg, 412 96, Gothenburg, Sweden. .,Department of Applied Physics, School of Engineering Sciences, KTH Royal Institute of Technology, 100 44, Stockholm, Sweden.
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13
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Guang Y, Ran K, Zhang J, Liu Y, Zhang S, Qiu X, Peng Y, Zhang X, Weigand M, Gräfe J, Schütz G, van der Laan G, Hesjedal T, Zhang S, Yu G, Han X. Superposition of Emergent Monopole and Antimonopole in CoTb Thin Films. Phys Rev Lett 2021; 127:217201. [PMID: 34860082 DOI: 10.1103/physrevlett.127.217201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Accepted: 10/19/2021] [Indexed: 06/13/2023]
Abstract
A three-dimensional singular point that consists of two oppositely aligned emergent monopoles is identified in continuous CoTb thin films, as confirmed by complementary techniques of resonant elastic x-ray scattering, Lorentz transmission electron microscopy, and scanning transmission x-ray microscopy. This new type of topological defect can be regarded as a superposition of an emergent magnetic monopole and an antimonopole, around which the source and drain of the magnetic flux overlap in space. We experimentally prove that the observed spin twist seen in Lorentz transmission electron microscopy reveals the cross section of the superimposed three-dimensional structure, providing a straightforward strategy for the observation of magnetic singularities. Such a quasiparticle provides an excellent platform for studying the rich physics of emergent electromagnetism.
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Affiliation(s)
- Yao Guang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Kejing Ran
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
- ShanghaiTech Laboratory for Topological Physics, ShanghaiTech University, Shanghai 201210, China
| | - Junwei Zhang
- School of Materials and Energy, Electron Microscopy Centre of Lanzhou University and Key Laboratory of Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou 730000, People's Republic of China
| | - Yizhou Liu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Senfu Zhang
- Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou University, Lanzhou 730000, China
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Xuepeng Qiu
- Shanghai Key Laboratory of Special Artificial Microstructure Materials & School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
| | - Yong Peng
- School of Materials and Energy, Electron Microscopy Centre of Lanzhou University and Key Laboratory of Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou 730000, People's Republic of China
| | - Xixiang Zhang
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Markus Weigand
- Max-Planck-Institut für Intelligente Systeme, Stuttgart 70569, Germany
| | - Joachim Gräfe
- Max-Planck-Institut für Intelligente Systeme, Stuttgart 70569, Germany
| | - Gisela Schütz
- Max-Planck-Institut für Intelligente Systeme, Stuttgart 70569, Germany
| | - Gerrit van der Laan
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
| | - Thorsten Hesjedal
- Department of Physics, Clarendon Laboratory, University of Oxford, Oxford OX1 3PU, United Kingdom
| | - Shilei Zhang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
- ShanghaiTech Laboratory for Topological Physics, ShanghaiTech University, Shanghai 201210, China
| | - Guoqiang Yu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Xiufeng Han
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
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14
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Dogan G, Demir SO, Gutzler R, Gruhn H, Dayan CB, Sanli UT, Silber C, Culha U, Sitti M, Schütz G, Grévent C, Keskinbora K. Bayesian Machine Learning for Efficient Minimization of Defects in ALD Passivation Layers. ACS Appl Mater Interfaces 2021; 13:54503-54515. [PMID: 34735111 PMCID: PMC8603353 DOI: 10.1021/acsami.1c14586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Accepted: 10/07/2021] [Indexed: 06/13/2023]
Abstract
Atomic layer deposition (ALD) is an enabling technology for encapsulating sensitive materials owing to its high-quality, conformal coating capability. Finding the optimum deposition parameters is vital to achieving defect-free layers; however, the high dimensionality of the parameter space makes a systematic study on the improvement of the protective properties of ALD films challenging. Machine-learning (ML) methods are gaining credibility in materials science applications by efficiently addressing these challenges and outperforming conventional techniques. Accordingly, this study reports the ML-based minimization of defects in an ALD-Al2O3 passivation layer for the corrosion protection of metallic copper using Bayesian optimization (BO). In all experiments, BO consistently minimizes the layer defect density by finding the optimum deposition parameters in less than three trials. Electrochemical tests show that the optimized layers have virtually zero film porosity and achieve five orders of magnitude reduction in corrosion current as compared to control samples. Optimized parameters of surface pretreatment using Ar/H2 plasma, the deposition temperature above 200 °C, and 60 ms pulse time quadruple the corrosion resistance. The significant optimization of ALD layers presented in this study demonstrates the effectiveness of BO and its potential outreach to a broader audience, focusing on different materials and processes in materials science applications.
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Affiliation(s)
- Gül Dogan
- Robert
Bosch GmbH, Automotive Electronics, Postfach 13 42, 72703 Reutlingen, Germany
- Max
Planck Institute for Intelligent Systems, Heisenbergstr 3, 70569 Stuttgart, Germany
| | - Sinan O. Demir
- Max
Planck Institute for Intelligent Systems, Heisenbergstr 3, 70569 Stuttgart, Germany
| | - Rico Gutzler
- Max
Planck Institute for Solid State Research, Heisenbergstr 1, 70569 Stuttgart, Germany
| | - Herbert Gruhn
- Robert
Bosch GmbH, Corporate Sector Research and Advance Engineering , Robert-Bosch-Campus1, 71272 Stuttgart, Germany
| | - Cem B. Dayan
- Max
Planck Institute for Intelligent Systems, Heisenbergstr 3, 70569 Stuttgart, Germany
| | - Umut T. Sanli
- Max
Planck Institute for Intelligent Systems, Heisenbergstr 3, 70569 Stuttgart, Germany
| | - Christian Silber
- Robert
Bosch GmbH, Automotive Electronics, Postfach 13 42, 72703 Reutlingen, Germany
| | - Utku Culha
- Max
Planck Institute for Intelligent Systems, Heisenbergstr 3, 70569 Stuttgart, Germany
| | - Metin Sitti
- Max
Planck Institute for Intelligent Systems, Heisenbergstr 3, 70569 Stuttgart, Germany
| | - Gisela Schütz
- Max
Planck Institute for Intelligent Systems, Heisenbergstr 3, 70569 Stuttgart, Germany
| | - Corinne Grévent
- Robert
Bosch GmbH, Automotive Electronics, Postfach 13 42, 72703 Reutlingen, Germany
| | - Kahraman Keskinbora
- Max
Planck Institute for Intelligent Systems, Heisenbergstr 3, 70569 Stuttgart, Germany
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15
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Kim S, Muhammad R, Schuetzenduebe P, Kalidindi SB, Schütz G, Oh H, Son K. Hybrids of Pd Nanoparticles and Metal-Organic Frameworks for Enhanced Magnetism. J Phys Chem Lett 2021; 12:4742-4748. [PMID: 33983024 PMCID: PMC8279731 DOI: 10.1021/acs.jpclett.1c01108] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 05/10/2021] [Indexed: 06/12/2023]
Abstract
Nonmagnetic Pd exhibits ferromagnetism in the nanosize regime. Various stabilization agents, including surfactants, metal oxide supports, polymers, and porous materials (e.g., metal-organic frameworks (MOFs)), have been employed to prevent the agglomeration of metal nanoparticles. However, magnetic properties are greatly affected by the structural and electronic changes imposed by these stabilizing agents. In particular, metal-MOF hybrids (NPs@MOFs) have reduced magnetic properties, as reported by several authors. Herein, we report the enhancement in magnetic properties resulting from the combination of magnetic Pd NPs with UiO-66(Hf), which exhibits ferromagnetism, and the corresponding modifications in the hybridized structures. These hybridized structures are found to be strongly ferromagnetic, showing high magnetization and coercivity. We observed that the magnetic property is enhanced by 2 to 3 times upon including the Pd NPs on the surface of a UiO-66(Hf) shell support. For a fundamental understanding, the magnetization (M-H data) of the hybridized structure is analyzed with a modified Langevin function.
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Affiliation(s)
- Suhwan Kim
- Department
of Energy Engineering, Gyeongsang National
University, Jinju 52725, Republic of Korea
| | - Raeesh Muhammad
- Department
of Energy Engineering, Gyeongsang National
University, Jinju 52725, Republic of Korea
| | | | - Suresh Babu Kalidindi
- Inorganic
and Analytical Chemistry Department, School of Chemistry, Andhra University, Visakhapatnam 530003, India
| | - Gisela Schütz
- Max
Planck Institute for Intelligent Systems, Stuttgart D-70569, Germany
| | - Hyunchul Oh
- Department
of Energy Engineering, Gyeongsang National
University, Jinju 52725, Republic of Korea
- Future
Convergence Technology Research Institute, Jinju 52725, Republic
of Korea
| | - Kwanghyo Son
- Max
Planck Institute for Intelligent Systems, Stuttgart D-70569, Germany
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16
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Träger N, Gruszecki P, Lisiecki F, Groß F, Förster J, Weigand M, Głowiński H, Kuświk P, Dubowik J, Schütz G, Krawczyk M, Gräfe J. Real-Space Observation of Magnon Interaction with Driven Space-Time Crystals. Phys Rev Lett 2021; 126:057201. [PMID: 33605763 DOI: 10.1103/physrevlett.126.057201] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 08/14/2020] [Accepted: 12/09/2020] [Indexed: 06/12/2023]
Abstract
The concept of space-time crystals (STC), i.e., translational symmetry breaking in time and space, was recently proposed and experimentally demonstrated for quantum systems. Here, we transfer this concept to magnons and experimentally demonstrate a driven STC at room temperature. The STC is realized by strong homogeneous microwave pumping of a micron-sized permalloy (Py) stripe and is directly imaged by scanning transmission x-ray microscopy (STXM). For a fundamental understanding of the formation of the STC, micromagnetic simulations are carefully adapted to model the experimental findings. Beyond the mere generation of a STC, we observe the formation of a magnonic band structure due to back folding of modes at the STC's Brillouin zone boundaries. We show interactions of magnons with the STC that appear as lattice scattering, which results in the generation of ultrashort spin waves (SW) down to 100-nm wavelengths that cannot be described by classical dispersion relations for linear SW excitation. We expect that room-temperature STCs will be useful to investigate nonlinear wave physics, as they can be easily generated and manipulated to control their spatial and temporal band structures.
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Affiliation(s)
- Nick Träger
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569 Stuttgart, Germany
| | - Paweł Gruszecki
- Adam Mickiewicz University, Faculty of Physics, ul. Uniwersytetu Poznańskiego 2, 61-614 Poznań, Poland
| | - Filip Lisiecki
- Institute of Molecular Physics, Polish Academy of Sciences, Mariana Smoluchowskiego 17, 60-179 Poznań, Poland
| | - Felix Groß
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569 Stuttgart, Germany
| | - Johannes Förster
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569 Stuttgart, Germany
| | - Markus Weigand
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569 Stuttgart, Germany
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Str. 15, 12489 Berlin, Germany
| | - Hubert Głowiński
- Institute of Molecular Physics, Polish Academy of Sciences, Mariana Smoluchowskiego 17, 60-179 Poznań, Poland
| | - Piotr Kuświk
- Institute of Molecular Physics, Polish Academy of Sciences, Mariana Smoluchowskiego 17, 60-179 Poznań, Poland
| | - Janusz Dubowik
- Institute of Molecular Physics, Polish Academy of Sciences, Mariana Smoluchowskiego 17, 60-179 Poznań, Poland
| | - Gisela Schütz
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569 Stuttgart, Germany
| | - Maciej Krawczyk
- Adam Mickiewicz University, Faculty of Physics, ul. Uniwersytetu Poznańskiego 2, 61-614 Poznań, Poland
| | - Joachim Gräfe
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569 Stuttgart, Germany
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17
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Groß F, Zelent M, Träger N, Förster J, Sanli UT, Sauter R, Decker M, Back CH, Weigand M, Keskinbora K, Schütz G, Krawczyk M, Gräfe J. Building Blocks for Magnon Optics: Emission and Conversion of Short Spin Waves. ACS Nano 2020; 14:17184-17193. [PMID: 33253544 PMCID: PMC7760108 DOI: 10.1021/acsnano.0c07076] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Accepted: 11/23/2020] [Indexed: 05/31/2023]
Abstract
Magnons have proven to be a promising candidate for low-power wave-based computing. The ability to encode information not only in amplitude but also in phase allows for increased data transmission rates. However, efficiently exciting nanoscale spin waves for a functional device requires sophisticated lithography techniques and therefore, remains a challenge. Here, we report on a method to measure the full spin wave isofrequency contour for a given frequency and field. A single antidot within a continuous thin film excites wave vectors along all directions within a single excitation geometry. Varying structural parameters or introducing Dzyaloshinskii-Moriya interaction allows the manipulation and control of the isofrequency contour, which is desirable for the fabrication of future magnonic devices. Additionally, the same antidot structure is utilized as a multipurpose spin wave device. Depending on its position with respect to the microstrip antenna, it can either be an emitter for short spin waves or a directional converter for incoming plane waves. Using simulations we show that such a converter structure is capable of generating a coherent spin wave beam. By introducing a short wavelength spin wave beam into existing magnonic gate logic, it is conceivable to reduce the size of devices to the micrometer scale. This method gives access to short wavelength spin waves to a broad range of magnonic devices without the need for refined sample preparation techniques. The presented toolbox for spin wave manipulation, emission, and conversion is a crucial step for spin wave optics and gate logic.
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Affiliation(s)
- Felix Groß
- Max
Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - Mateusz Zelent
- Faculty
of Physics, Adam Mickiewicz University, Poznań, 61-614 Poznań, Poland
| | - Nick Träger
- Max
Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - Johannes Förster
- Max
Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - Umut T. Sanli
- Max
Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - Robert Sauter
- Max
Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - Martin Decker
- Technical
University Munich, 85748 Garching, Germany
| | | | - Markus Weigand
- Helmholtz-Zentrum
Berlin für Materialien und Energie, 12489 Berlin, Germany
| | | | - Gisela Schütz
- Max
Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - Maciej Krawczyk
- Faculty
of Physics, Adam Mickiewicz University, Poznań, 61-614 Poznań, Poland
| | - Joachim Gräfe
- Max
Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
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18
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Talmelli G, Devolder T, Träger N, Förster J, Wintz S, Weigand M, Stoll H, Heyns M, Schütz G, Radu IP, Gräfe J, Ciubotaru F, Adelmann C. Reconfigurable submicrometer spin-wave majority gate with electrical transducers. Sci Adv 2020; 6:6/51/eabb4042. [PMID: 33355122 DOI: 10.1126/sciadv.abb4042] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 11/06/2020] [Indexed: 06/12/2023]
Abstract
Spin waves are excitations in ferromagnetic media that have been proposed as information carriers in hybrid spintronic devices with much lower operation power than conventional charge-based electronics. Their wave nature can be exploited in majority gates by using interference for computation. However, a scalable spin-wave majority gate that can be cointegrated alongside conventional electronics is still lacking. Here, we demonstrate a submicrometer inline spin-wave majority gate with fan-out. Time-resolved imaging of the magnetization dynamics by scanning transmission x-ray microscopy illustrates the device operation. All-electrical spin-wave spectroscopy further demonstrates majority gates with submicrometer dimensions, reconfigurable input and output ports, and frequency-division multiplexing. Challenges for hybrid spintronic computing systems based on spin-wave majority gates are discussed.
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Affiliation(s)
- Giacomo Talmelli
- Imec, 3001 Leuven, Belgium
- KU Leuven, Departement Materiaalkunde, SIEM, 3001 Leuven, Belgium
| | - Thibaut Devolder
- Centre de Nanosciences et de Nanotechnologies, CNRS, Université Paris-Sud and Université Paris-Saclay, 91120 Palaiseau, France
| | - Nick Träger
- Max-Planck-Institut für Intelligente Systeme, 70569 Stuttgart, Germany
| | - Johannes Förster
- Max-Planck-Institut für Intelligente Systeme, 70569 Stuttgart, Germany
| | - Sebastian Wintz
- Max-Planck-Institut für Intelligente Systeme, 70569 Stuttgart, Germany
- Paul Scherrer Institut, 5232 Villigen, Switzerland
| | - Markus Weigand
- Max-Planck-Institut für Intelligente Systeme, 70569 Stuttgart, Germany
- Helmholtz-Zentrum Berlin, 12489 Berlin, Germany
| | - Hermann Stoll
- Max-Planck-Institut für Intelligente Systeme, 70569 Stuttgart, Germany
- Institut für Physik, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
| | - Marc Heyns
- Imec, 3001 Leuven, Belgium
- KU Leuven, Departement Materiaalkunde, SIEM, 3001 Leuven, Belgium
| | - Gisela Schütz
- Max-Planck-Institut für Intelligente Systeme, 70569 Stuttgart, Germany
| | | | - Joachim Gräfe
- Max-Planck-Institut für Intelligente Systeme, 70569 Stuttgart, Germany
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19
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Träger N, Groß F, Förster J, Baumgaertl K, Stoll H, Weigand M, Schütz G, Grundler D, Gräfe J. Single shot acquisition of spatially resolved spin wave dispersion relations using X-ray microscopy. Sci Rep 2020; 10:18146. [PMID: 33097751 PMCID: PMC7584636 DOI: 10.1038/s41598-020-74785-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 10/06/2020] [Indexed: 11/30/2022] Open
Abstract
For understanding magnonic materials the fundamental characterization of their frequency response is essential. However, determining full dispersion relations and real space wavelength measurements are challenging and time-consuming tasks. We present an approach for spin wave excitation by a modified Sinc pulse, which combines a cosine signal with a conventional Sinc function. The resulting adjustable frequency bands lead to a broadband spin wave excitation at uniform power levels. Subsequently, time resolved scanning transmission X-ray microscopy is used for direct imaging of all excited spin waves in real space. To demonstrate the capabilities of this approach, a modified Sinc excitation of an ultra-thin yttrium-iron-garnet film is shown that simultaneously reveals phase, amplitude, and k-space information from a single measurement. Consequently, this approach allows a fast and thorough access to the full dispersion relation including spatial maps of the individual spin wave modes, enabling complete characterization of magnonic materials down to the nanoscale in real and reciprocal space.
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Affiliation(s)
- Nick Träger
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany.
| | - Felix Groß
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - Johannes Förster
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - Korbinian Baumgaertl
- Laboratory of Nanoscale Magnetic Materials and Magnonics, Institute of Materials, EPFL, 1015, Lausanne, Switzerland
| | - Hermann Stoll
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany.,Institute of Physics, Johannes Gutenberg-University Mainz, 55099, Mainz, Germany
| | - Markus Weigand
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany.,Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, 12489, Berlin, Germany
| | - Gisela Schütz
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - Dirk Grundler
- Laboratory of Nanoscale Magnetic Materials and Magnonics, Institute of Materials, EPFL, 1015, Lausanne, Switzerland
| | - Joachim Gräfe
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany.
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20
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Baumgaertl K, Gräfe J, Che P, Mucchietto A, Förster J, Träger N, Bechtel M, Weigand M, Schütz G, Grundler D. Nanoimaging of Ultrashort Magnon Emission by Ferromagnetic Grating Couplers at GHz Frequencies. Nano Lett 2020; 20:7281-7286. [PMID: 32830984 PMCID: PMC7564445 DOI: 10.1021/acs.nanolett.0c02645] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 08/22/2020] [Indexed: 06/11/2023]
Abstract
On-chip signal processing at microwave frequencies is key for modern mobile communication. When one aims at small footprints, low power consumption, reprogrammable filters, and delay lines, magnons in low-damping ferrimagnets offer great promise. Ferromagnetic grating couplers have been reported to be specifically useful as microwave-to-magnon transducers. However, their interconversion efficiency is unknown and real-space measurements of the emitted magnon wavelengths have not yet been accomplished. Here, we image with subwavelength spatial resolution the magnon emission process into ferrimagnetic yttrium iron garnet (YIG) at frequencies up to 8 GHz. We evidence propagating magnons of a wavelength of 98.7 nm underneath the gratings, which enter the YIG without a phase jump. Counterintuitively, the magnons exhibit an even increased amplitude in YIG, which is unexpected and due to a further wavelength conversion process. Our results are of key importance for magnonic components, which efficiently control microwave signals on the nanoscale.
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Affiliation(s)
- Korbinian Baumgaertl
- Laboratory
of Nanoscale Magnetic Materials and Magnonics, Institute of Materials
(IMX), École Polytechnique Fédérale
de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Joachim Gräfe
- Max-Planck-Institute
for Intelligent Systems, D-70569 Stuttgart, Germany
| | - Ping Che
- Laboratory
of Nanoscale Magnetic Materials and Magnonics, Institute of Materials
(IMX), École Polytechnique Fédérale
de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Andrea Mucchietto
- Laboratory
of Nanoscale Magnetic Materials and Magnonics, Institute of Materials
(IMX), École Polytechnique Fédérale
de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Johannes Förster
- Max-Planck-Institute
for Intelligent Systems, D-70569 Stuttgart, Germany
| | - Nick Träger
- Max-Planck-Institute
for Intelligent Systems, D-70569 Stuttgart, Germany
| | - Michael Bechtel
- Max-Planck-Institute
for Intelligent Systems, D-70569 Stuttgart, Germany
| | - Markus Weigand
- Max-Planck-Institute
for Intelligent Systems, D-70569 Stuttgart, Germany
- Helmholtz-Zentrum
Berlin für Materialien und Energie, D-14109 Berlin, Germany
| | - Gisela Schütz
- Max-Planck-Institute
for Intelligent Systems, D-70569 Stuttgart, Germany
| | - Dirk Grundler
- Laboratory
of Nanoscale Magnetic Materials and Magnonics, Institute of Materials
(IMX), École Polytechnique Fédérale
de Lausanne (EPFL), 1015 Lausanne, Switzerland
- Institute
of Microengineering (IMT), École
Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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21
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Wu H, Groß F, Dai B, Lujan D, Razavi SA, Zhang P, Liu Y, Sobotkiewich K, Förster J, Weigand M, Schütz G, Li X, Gräfe J, Wang KL. Ferrimagnetic Skyrmions in Topological Insulator/Ferrimagnet Heterostructures. Adv Mater 2020; 32:e2003380. [PMID: 32666575 DOI: 10.1002/adma.202003380] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Indexed: 06/11/2023]
Abstract
Magnetic skyrmions are topologically nontrivial chiral spin textures that have potential applications in next-generation energy-efficient and high-density spintronic devices. In general, the chiral spins of skyrmions are stabilized by the noncollinear Dzyaloshinskii-Moriya interaction (DMI), originating from the inversion symmetry breaking combined with the strong spin-orbit coupling (SOC). Here, the strong SOC from topological insulators (TIs) is utilized to provide a large interfacial DMI in TI/ferrimagnet heterostructures at room temperature, resulting in small-size (radius ≈ 100 nm) skyrmions in the adjacent ferrimagnet. Antiferromagnetically coupled skyrmion sublattices are observed in the ferrimagnet by element-resolved scanning transmission X-ray microscopy, showing the potential of a vanishing skyrmion Hall effect and ultrafast skyrmion dynamics. The line-scan spin profile of the single skyrmion shows a Néel-type domain wall structure and a 120 nm size of the 180° domain wall. This work demonstrates the sizable DMI and small skyrmions in TI-based heterostructures with great promise for low-energy spintronic devices.
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Affiliation(s)
- Hao Wu
- Department of Electrical and Computer Engineering, and Department of Physics and Astronomy, University of California, Los Angeles, CA, 90095, USA
| | - Felix Groß
- Max Planck Institute for Intelligent Systems, Heisenbergstraße 3, Stuttgart, 70569, Germany
| | - Bingqian Dai
- Department of Electrical and Computer Engineering, and Department of Physics and Astronomy, University of California, Los Angeles, CA, 90095, USA
| | - David Lujan
- Department of Physics, and Center for Complex Quantum Systems, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Seyed Armin Razavi
- Department of Electrical and Computer Engineering, and Department of Physics and Astronomy, University of California, Los Angeles, CA, 90095, USA
| | - Peng Zhang
- Department of Electrical and Computer Engineering, and Department of Physics and Astronomy, University of California, Los Angeles, CA, 90095, USA
| | - Yuxiang Liu
- Department of Electrical and Computer Engineering, and Department of Physics and Astronomy, University of California, Los Angeles, CA, 90095, USA
| | - Kemal Sobotkiewich
- Department of Physics, and Center for Complex Quantum Systems, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Johannes Förster
- Max Planck Institute for Intelligent Systems, Heisenbergstraße 3, Stuttgart, 70569, Germany
| | - Markus Weigand
- Max Planck Institute for Intelligent Systems, Heisenbergstraße 3, Stuttgart, 70569, Germany
| | - Gisela Schütz
- Max Planck Institute for Intelligent Systems, Heisenbergstraße 3, Stuttgart, 70569, Germany
| | - Xiaoqin Li
- Department of Physics, and Center for Complex Quantum Systems, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Joachim Gräfe
- Max Planck Institute for Intelligent Systems, Heisenbergstraße 3, Stuttgart, 70569, Germany
| | - Kang L Wang
- Department of Electrical and Computer Engineering, and Department of Physics and Astronomy, University of California, Los Angeles, CA, 90095, USA
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22
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Dogan G, Sanli UT, Hahn K, Müller L, Gruhn H, Silber C, Schütz G, Grévent C, Keskinbora K. In Situ X-ray Diffraction and Spectro-Microscopic Study of ALD Protected Copper Films. ACS Appl Mater Interfaces 2020; 12:33377-33385. [PMID: 32551474 DOI: 10.1021/acsami.0c06873] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In many applications of copper in industry and research, copper migration and degradation of metallic copper to its oxides is a common problem. There are numerous ways to overcome this degradation with varying success. Atomic layer deposition (ALD) based encapsulation and passivation of the metallic copper recently emerged as a serious route to success owing to the conformality and density of the ALD films. So far, the majority of the studies have been focused on corrosion protection of copper in a variety of chemical environments, mostly at ambient temperature. An investigation of the stability of the ALD film stacks and copper's interaction with them at elevated temperatures has been lacking. Here, we study the mitigation of copper oxidation and migration in 50 nm thick Al2O3/TiO2 and Al2O3/SiO2 bilayer ALD stacks. First, the corrosion dynamics were investigated via in situ X-ray diffraction (XRD) at 350 °C under atmospheric conditions, and second, the interaction of copper with the passivation layers have been examined post factum using detailed spectro-microscopic investigations. According to the XRD results, both ALD films exhibited excellent oxidation protection. In contrast, bare Cu immediately started to oxidize at 350 °C and transformed entirely to its known oxide phases in 4 h. Spectro-microscopic studies revealed that there are structural and chemical changes on the top surface and within the film stacks. The TiO2 layer was crystallized during annealing, while the SiO2 layer stayed in the amorphous phase, which was analyzed by grazing incidence XRD and transmission electron microscopy. According to scanning electron microscopy and X-ray photoelectron spectroscopy analysis, copper was detected on the surface with a higher amount in Al2O3/TiO2 than Al2O3/SiO2, 5.2 at.% and 0.7 at.%, respectively. Based on the surface and cross-sectional analysis, copper migration was observed on both layers, albeit more substantially in Al2O3/TiO2. In the case of Al2O3/SiO2, the bulk of the copper was captured at the interface of the two oxides.
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Affiliation(s)
- Gül Dogan
- Robert Bosch GmbH, Automotive Electronics, Postfach 13 42, 72703 Reutlingen, Germany
- Max Planck Institute for Intelligent Systems, Heisenbergstrasse 3, 70569 Stuttgart, Germany
| | - Umut T Sanli
- Max Planck Institute for Intelligent Systems, Heisenbergstrasse 3, 70569 Stuttgart, Germany
| | - Kersten Hahn
- Max Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569 Stuttgart, Germany
| | - Lutz Müller
- Robert Bosch GmbH, Automotive Electronics, Postfach 13 42, 72703 Reutlingen, Germany
| | - Herbert Gruhn
- Robert Bosch GmbH, Corporate Sector Research and Advance Engineering, Robert-Bosch-Campus1, 71272 Stuttgart, Germany
| | - Christian Silber
- Robert Bosch GmbH, Automotive Electronics, Postfach 13 42, 72703 Reutlingen, Germany
| | - Gisela Schütz
- Max Planck Institute for Intelligent Systems, Heisenbergstrasse 3, 70569 Stuttgart, Germany
| | - Corinne Grévent
- Robert Bosch GmbH, Automotive Electronics, Postfach 13 42, 72703 Reutlingen, Germany
| | - Kahraman Keskinbora
- Max Planck Institute for Intelligent Systems, Heisenbergstrasse 3, 70569 Stuttgart, Germany
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23
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Kadiri VM, Bussi C, Holle AW, Son K, Kwon H, Schütz G, Gutierrez MG, Fischer P. Biocompatible Magnetic Micro- and Nanodevices: Fabrication of FePt Nanopropellers and Cell Transfection. Adv Mater 2020; 32:e2001114. [PMID: 32378269 DOI: 10.1002/adma.202001114] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 03/23/2020] [Accepted: 03/25/2020] [Indexed: 05/22/2023]
Abstract
The application of nanoparticles for drug or gene delivery promises benefits in the form of single-cell-specific therapeutic and diagnostic capabilities. Many methods of cell transfection rely on unspecific means to increase the transport of genetic material into cells. Targeted transport is in principle possible with magnetically propelled micromotors, which allow responsive nanoscale actuation and delivery. However, many commonly used magnetic materials (e.g., Ni and Co) are not biocompatible, possess weak magnetic remanence (Fe3 O4 ), or cannot be implemented in nanofabrication schemes (NdFeB). Here, it is demonstrated that co-depositing iron (Fe) and platinum (Pt) followed by one single annealing step, without the need for solution processing, yields ferromagnetic FePt nanomotors that are noncytotoxic, biocompatible, and possess a remanence and magnetization that rival those of permanent NdFeB micromagnets. Active cell targeting and magnetic transfection of lung carcinoma cells are demonstrated using gradient-free rotating millitesla fields to drive the FePt nanopropellers. The carcinoma cells express enhanced green fluorescent protein after internalization and cell viability is unaffected by the presence of the FePt nanopropellers. The results establish FePt, prepared in the L10 phase, as a promising magnetic material for biomedical applications with superior magnetic performance, especially for micro- and nanodevices.
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Affiliation(s)
- Vincent Mauricio Kadiri
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, Stuttgart, 70569, Germany
- Institute of Physical Chemistry, University of Stuttgart, Pfaffenwaldring 55, Stuttgart, 70569, Germany
| | - Claudio Bussi
- Francis Crick Institute, 1 Midland Rd, London, NW1 1AT, UK
| | - Andrew W Holle
- Max Planck Institute for Medical Research, Jahnstraße 29, Heidelberg, 69120, Germany
| | - Kwanghyo Son
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, Stuttgart, 70569, Germany
| | - Hyunah Kwon
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, Stuttgart, 70569, Germany
| | - Gisela Schütz
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, Stuttgart, 70569, Germany
| | | | - Peer Fischer
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, Stuttgart, 70569, Germany
- Institute of Physical Chemistry, University of Stuttgart, Pfaffenwaldring 55, Stuttgart, 70569, Germany
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24
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Liu M, Zhang L, Little MA, Kapil V, Ceriotti M, Yang S, Ding L, Holden DL, Balderas-Xicohténcatl R, He D, Clowes R, Chong SY, Schütz G, Chen L, Hirscher M, Cooper AI. Barely porous organic cages for hydrogen isotope separation. Science 2020; 366:613-620. [PMID: 31672893 DOI: 10.1126/science.aax7427] [Citation(s) in RCA: 140] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 10/10/2019] [Indexed: 01/18/2023]
Abstract
The separation of hydrogen isotopes for applications such as nuclear fusion is a major challenge. Current technologies are energy intensive and inefficient. Nanoporous materials have the potential to separate hydrogen isotopes by kinetic quantum sieving, but high separation selectivity tends to correlate with low adsorption capacity, which can prohibit process scale-up. In this study, we use organic synthesis to modify the internal cavities of cage molecules to produce hybrid materials that are excellent quantum sieves. By combining small-pore and large-pore cages together in a single solid, we produce a material with optimal separation performance that combines an excellent deuterium/hydrogen selectivity (8.0) with a high deuterium uptake (4.7 millimoles per gram).
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Affiliation(s)
- Ming Liu
- Materials Innovation Factory and Department of Chemistry, University of Liverpool, 51 Oxford Street, Liverpool, L7 3NY, UK
| | - Linda Zhang
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569 Stuttgart, Germany
| | - Marc A Little
- Materials Innovation Factory and Department of Chemistry, University of Liverpool, 51 Oxford Street, Liverpool, L7 3NY, UK
| | - Venkat Kapil
- Laboratory of Computational Science and Modeling, Institute of Materials, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Michele Ceriotti
- Laboratory of Computational Science and Modeling, Institute of Materials, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Siyuan Yang
- Department of Chemistry, Xi'an JiaoTong-Liverpool University, 111 Ren'ai Road, Suzhou Dushu Lake Higher Education Town, Jiangsu Province, 215123, China
| | - Lifeng Ding
- Department of Chemistry, Xi'an JiaoTong-Liverpool University, 111 Ren'ai Road, Suzhou Dushu Lake Higher Education Town, Jiangsu Province, 215123, China
| | - Daniel L Holden
- Materials Innovation Factory and Department of Chemistry, University of Liverpool, 51 Oxford Street, Liverpool, L7 3NY, UK
| | | | - Donglin He
- Materials Innovation Factory and Department of Chemistry, University of Liverpool, 51 Oxford Street, Liverpool, L7 3NY, UK
| | - Rob Clowes
- Materials Innovation Factory and Department of Chemistry, University of Liverpool, 51 Oxford Street, Liverpool, L7 3NY, UK
| | - Samantha Y Chong
- Materials Innovation Factory and Department of Chemistry, University of Liverpool, 51 Oxford Street, Liverpool, L7 3NY, UK
| | - Gisela Schütz
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569 Stuttgart, Germany
| | - Linjiang Chen
- Materials Innovation Factory and Department of Chemistry, University of Liverpool, 51 Oxford Street, Liverpool, L7 3NY, UK.,Leverhulme Research Centre for Functional Materials Design, Materials Innovation Factory and Department of Chemistry, University of Liverpool, 51 Oxford Street, Liverpool, L7 3NY, UK
| | - Michael Hirscher
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569 Stuttgart, Germany.
| | - Andrew I Cooper
- Materials Innovation Factory and Department of Chemistry, University of Liverpool, 51 Oxford Street, Liverpool, L7 3NY, UK. .,Leverhulme Research Centre for Functional Materials Design, Materials Innovation Factory and Department of Chemistry, University of Liverpool, 51 Oxford Street, Liverpool, L7 3NY, UK
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25
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Birch MT, Cortés-Ortuño D, Turnbull LA, Wilson MN, Groß F, Träger N, Laurenson A, Bukin N, Moody SH, Weigand M, Schütz G, Popescu H, Fan R, Steadman P, Verezhak JAT, Balakrishnan G, Loudon JC, Twitchett-Harrison AC, Hovorka O, Fangohr H, Ogrin FY, Gräfe J, Hatton PD. Real-space imaging of confined magnetic skyrmion tubes. Nat Commun 2020; 11:1726. [PMID: 32265449 PMCID: PMC7138844 DOI: 10.1038/s41467-020-15474-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 03/13/2020] [Indexed: 11/23/2022] Open
Abstract
Magnetic skyrmions are topologically nontrivial particles with a potential application as information elements in future spintronic device architectures. While they are commonly portrayed as two dimensional objects, in reality magnetic skyrmions are thought to exist as elongated, tube-like objects extending through the thickness of the host material. The study of this skyrmion tube state (SkT) is vital for furthering the understanding of skyrmion formation and dynamics for future applications. However, direct experimental imaging of skyrmion tubes has yet to be reported. Here, we demonstrate the real-space observation of skyrmion tubes in a lamella of FeGe using resonant magnetic x-ray imaging and comparative micromagnetic simulations, confirming their extended structure. The formation of these structures at the edge of the sample highlights the importance of confinement and edge effects in the stabilisation of the SkT state, opening the door to further investigation into this unexplored dimension of the skyrmion spin texture.
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Affiliation(s)
- M T Birch
- Centre for Materials Physics, Durham University, Durham, DH1 3LE, UK
- Diamond Light Source, Didcot, OX11 0DE, UK
| | - D Cortés-Ortuño
- Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - L A Turnbull
- Centre for Materials Physics, Durham University, Durham, DH1 3LE, UK
| | - M N Wilson
- Centre for Materials Physics, Durham University, Durham, DH1 3LE, UK
| | - F Groß
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - N Träger
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - A Laurenson
- School of Physics and Astronomy, University of Exeter, Exeter, EX4 4QL, UK
| | - N Bukin
- School of Physics and Astronomy, University of Exeter, Exeter, EX4 4QL, UK
| | - S H Moody
- Centre for Materials Physics, Durham University, Durham, DH1 3LE, UK
| | - M Weigand
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Institut Nanospektroskopie, Kekuléstrasse 5, 12489, Berlin, Germany
| | - G Schütz
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - H Popescu
- Synchrotron SOLEIL, Saint Aubin, BP 48, 91192, Gif-sur-Yvette, France
| | - R Fan
- Diamond Light Source, Didcot, OX11 0DE, UK
| | - P Steadman
- Diamond Light Source, Didcot, OX11 0DE, UK
| | - J A T Verezhak
- Department of Physics, University of Warwick, Coventry, CV4 7AL, UK
| | - G Balakrishnan
- Department of Physics, University of Warwick, Coventry, CV4 7AL, UK
| | - J C Loudon
- Department of Materials Science and Metallurgy, University of Cambridge, Cambridge, CB3 0FS, UK
| | - A C Twitchett-Harrison
- Department of Materials Science and Metallurgy, University of Cambridge, Cambridge, CB3 0FS, UK
| | - O Hovorka
- Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - H Fangohr
- Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, SO17 1BJ, UK
- European XFEL GmbH, Holzkoppel 4, 22869, Schenefeld, Germany
| | - F Y Ogrin
- School of Physics and Astronomy, University of Exeter, Exeter, EX4 4QL, UK
| | - J Gräfe
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - P D Hatton
- Centre for Materials Physics, Durham University, Durham, DH1 3LE, UK.
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26
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Loetgering L, Baluktsian M, Keskinbora K, Horstmeyer R, Wilhein T, Schütz G, Eikema KSE, Witte S. Generation and characterization of focused helical x-ray beams. Sci Adv 2020; 6:eaax8836. [PMID: 32110725 PMCID: PMC7021491 DOI: 10.1126/sciadv.aax8836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 11/26/2019] [Indexed: 05/06/2023]
Abstract
The phenomenon of orbital angular momentum (OAM) affects a variety of important applications in visible optics, including optical tweezers, free-space communication, and 3D localization for fluorescence imaging. The lack of suitable wavefront shaping optics such as spatial light modulators has inhibited the ability to impart OAM on x-ray and electron radiation in a controlled way. Here, we report the experimental observation of helical soft x-ray beams generated by holographically designed diffractive optical elements. We demonstrate that these beams rotate as a function of propagation distance and measure their vorticity and coherent mode structure using ptychography. Our results establish an approach for controlling and shaping of complex focused beams for short wavelength scanning microscopy and OAM-driven applications.
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Affiliation(s)
- Lars Loetgering
- Advanced Research Center for Nanolithography, Science Park 106, 1098 XG Amsterdam, Netherlands
- Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, Netherlands
- Corresponding author. (L.L.); (S.W.)
| | - Margarita Baluktsian
- Max Planck Institute for Intelligent Systems, Heisenbergstraße 3, 70569 Stuttgart, Germany
| | - Kahraman Keskinbora
- Max Planck Institute for Intelligent Systems, Heisenbergstraße 3, 70569 Stuttgart, Germany
| | | | - Thomas Wilhein
- University of Applied Science Koblenz, Institute for X-Optics, Joseph-Rovan-Allee 2, 53424 Remagen, Germany
| | - Gisela Schütz
- Max Planck Institute for Intelligent Systems, Heisenbergstraße 3, 70569 Stuttgart, Germany
| | - Kjeld S. E. Eikema
- Advanced Research Center for Nanolithography, Science Park 106, 1098 XG Amsterdam, Netherlands
- Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, Netherlands
| | - Stefan Witte
- Advanced Research Center for Nanolithography, Science Park 106, 1098 XG Amsterdam, Netherlands
- Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, Netherlands
- Corresponding author. (L.L.); (S.W.)
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27
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Son K, Ryu G, Jeong HH, Fink L, Merz M, Nagel P, Schuppler S, Richter G, Goering E, Schütz G. Superior Magnetic Performance in FePt L1 0 Nanomaterials. Small 2019; 15:e1902353. [PMID: 31257719 DOI: 10.1002/smll.201902353] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 06/17/2019] [Indexed: 06/09/2023]
Abstract
The discovery of the high maximum energy product of 59 MGOe for NdFeB magnets is a breakthrough in the development of permanent magnets with a tremendous impact in many fields of technology. This value is still the world record, for 40 years. This work reports on a reliable and robust route to realize nearly perfectly ordered L10 -phase FePt nanoparticles, leading to an unprecedented energy product of 80 MGOe at room temperature. Furthermore, with a 3 nm Au coverage, the magnetic polarization of these nanomagnets can be enhanced by 25% exceeding 1.8 T. This exceptional magnetization and anisotropy is confirmed by using multiple imaging and spectroscopic methods, which reveal highly consistent results. Due to the unprecedented huge energy product, this material can be envisaged as a new advanced basic magnetic component in modern micro and nanosized devices.
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Affiliation(s)
- Kwanghyo Son
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, D-70569, Stuttgart, Germany
| | - Gihun Ryu
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, D-70569, Stuttgart, Germany
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzerstr. 40, D-01187, Dresden, Germany
| | - Hyeon-Ho Jeong
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, D-70569, Stuttgart, Germany
| | - Lukas Fink
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, D-70569, Stuttgart, Germany
| | - Michael Merz
- Karlsruhe Institute of Technology, Institute for Solid-State Physics, D-76021, Karlsruhe, Germany
| | - Peter Nagel
- Karlsruhe Institute of Technology, Institute for Solid-State Physics, D-76021, Karlsruhe, Germany
| | - Stefan Schuppler
- Karlsruhe Institute of Technology, Institute for Solid-State Physics, D-76021, Karlsruhe, Germany
| | - Gunther Richter
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, D-70569, Stuttgart, Germany
| | - Eberhard Goering
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, D-70569, Stuttgart, Germany
| | - Gisela Schütz
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, D-70569, Stuttgart, Germany
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28
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Yu P, Li J, Li X, Schütz G, Hirscher M, Zhang S, Liu N. Generation of Switchable Singular Beams with Dynamic Metasurfaces. ACS Nano 2019; 13:7100-7106. [PMID: 31083965 PMCID: PMC6595502 DOI: 10.1021/acsnano.9b02425] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 05/14/2019] [Indexed: 05/26/2023]
Abstract
Singular beams have attracted great attention due to their optical properties and broad applications from light manipulation to optical communications. However, there has been a lack of practical schemes with which to achieve switchable singular beams with sub-wavelength resolution using ultrathin and flat optical devices. In this work, we demonstrate the generation of switchable vector and vortex beams utilizing dynamic metasurfaces at visible frequencies. The dynamic functionality of the metasurface pixels is enabled by the utilization of magnesium nanorods, which possess plasmonic reconfigurability upon hydrogenation and dehydrogenation. We show that switchable vector beams of different polarization states and switchable vortex beams of different topological charges can be implemented through simple hydrogenation and dehydrogenation of the same metasurfaces. Furthermore, we demonstrate a two-cascade metasurface scheme for holographic pattern switching, taking inspiration from orbital angular momentum-shift keying. Our work provides an additional degree of freedom to develop high-security optical elements for anti-counterfeiting applications.
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Affiliation(s)
- Ping Yu
- Max
Planck Institute for Intelligent Systems, Heisenbergstrasse 3, 70569 Stuttgart, Germany
| | - Jianxiong Li
- Max
Planck Institute for Intelligent Systems, Heisenbergstrasse 3, 70569 Stuttgart, Germany
| | - Xin Li
- Beijing
Engineering Research Center for Mixed Reality and Advanced Display,
School of Optoelectronics, Beijing Institute
of Technology, South Zhongguancun Street 5, 100081 Beijing, China
| | - Gisela Schütz
- Max
Planck Institute for Intelligent Systems, Heisenbergstrasse 3, 70569 Stuttgart, Germany
| | - Michael Hirscher
- Max
Planck Institute for Intelligent Systems, Heisenbergstrasse 3, 70569 Stuttgart, Germany
| | - Shuang Zhang
- School
of Physics & Astronomy, University of
Birmingham, Birmingham B15 2TT, United Kingdom
| | - Na Liu
- Max
Planck Institute for Intelligent Systems, Heisenbergstrasse 3, 70569 Stuttgart, Germany
- Kirchhoff
Institute for Physics, University of Heidelberg, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany
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29
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Son K, Kim JY, Schütz G, Kang SG, Moon HR, Oh H. Coordinated Molecule-Modulated Magnetic Phase with Metamagnetism in Metal–Organic Frameworks. Inorg Chem 2019; 58:8895-8899. [PMID: 31184874 DOI: 10.1021/acs.inorgchem.9b00889] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kwanghyo Son
- Max Planck Institute for Intelligent Systems, Heisenbergstrasse 3, Stuttgart 70569, Germany
| | - Jin Yeong Kim
- Department of Chemistry, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Gisela Schütz
- Max Planck Institute for Intelligent Systems, Heisenbergstrasse 3, Stuttgart 70569, Germany
| | - Sung Gu Kang
- School of Chemical Engineering, University of Ulsan, Ulsan 44610, Republic of Korea
| | - Hoi Ri Moon
- Department of Chemistry, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Hyunchul Oh
- Department of Energy Engineering, Gyeongnam National University of Science and Technology, Jinju 52725, Republic of Korea
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30
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Ivanov YP, Soltan S, Albrecht J, Goering E, Schütz G, Zhang Z, Chuvilin A. The Route to Supercurrent Transparent Ferromagnetic Barriers in Superconducting Matrix. ACS Nano 2019; 13:5655-5661. [PMID: 30977633 PMCID: PMC8830211 DOI: 10.1021/acsnano.9b00888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 04/12/2019] [Indexed: 06/09/2023]
Abstract
A ferromagnetic barrier thinner than the coherence length in high-temperature superconductors is realized in the multilayers of YBa2Cu3O7-δ and La0.67Ca0.33MnO3. We used epitaxial growth of YBCO on ⟨110⟩ SrTiO3 substrates by pulsed laser deposition to prepare thin superconducting films with copper oxide planes oriented at an angle to the substrate surface. Subsequent deposition of LCMO and finally a second YBCO layer produces a superconductor/ferromagnet/superconductor trilayer containing an ultrathin ferromagnetic barrier with sophisticated geometry at which the long axis of coherence length ovoid of YBCO is pointing across the LCMO ferromagnetic layer. A detailed characterization of this structure is achieved using high-resolution electron microscopy.
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Affiliation(s)
- Yurii P. Ivanov
- Department
of Materials Science and Metallurgy, University
of Cambridge, Cambridge CB3 0FS, United Kingdom
- Erich
Schmid Institute of Materials Science, Austrian
Academy of Sciences, Jahnstraße 12, A-8700 Leoben, Austria
- School
of Natural Sciences, Far Eastern Federal
University, 690950 Vladivostok, Russia
| | - Soltan Soltan
- Department
of Physics, Faculty of Science, Helwan University, 11792 Cairo, Egypt
- Max-Planck-Institute
for Intelligent Systems, Heisenbergstr. 3, D-70569 Stuttgart, Germany
| | - Joachim Albrecht
- Research
Institute for Innovative Surfaces FINO, Beethovenstr. 1, D-73430 Aalen, Germany
| | - Eberhard Goering
- Max-Planck-Institute
for Intelligent Systems, Heisenbergstr. 3, D-70569 Stuttgart, Germany
| | - Gisela Schütz
- Max-Planck-Institute
for Intelligent Systems, Heisenbergstr. 3, D-70569 Stuttgart, Germany
| | - Zaoli Zhang
- Erich
Schmid Institute of Materials Science, Austrian
Academy of Sciences, Jahnstraße 12, A-8700 Leoben, Austria
| | - Andrey Chuvilin
- CIC
nanoGUNE Consolider, Av. de Tolosa 76, 20018 San Sebastian, Spain
- Basque
Foundation for Science, IKERBASQUE, Maria Diaz de Haro 3, 48013 Bilbao, Spain
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31
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Mondal SS, Kreuzer A, Behrens K, Schütz G, Holdt HJ, Hirscher M. Systematic Experimental Study on Quantum Sieving of Hydrogen Isotopes in Metal-Amide-Imidazolate Frameworks with narrow 1-D Channels. Chemphyschem 2019; 20:1311-1315. [PMID: 31017710 PMCID: PMC6619243 DOI: 10.1002/cphc.201900183] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Revised: 04/23/2019] [Indexed: 11/24/2022]
Abstract
Quantum sieving of hydrogen isotopes is experimentally studied in isostructural hexagonal metal‐organic frameworks having 1‐D channels, named IFP‐1, −3, −4 and −7. Inside the channels, different molecules or atoms restrict the channel diameter periodically with apertures larger (4.2 Å for IFP‐1, 3.1 Å for IFP‐3) and smaller (2.1 Å for IFP‐7, 1.7 Å for IFP‐4) than the kinetic diameter of hydrogen isotopes. From a geometrical point of view, no gas should penetrate into IFP‐7 and IFP‐4, but due to the thermally induced flexibility, so‐called gate‐opening effect of the apertures, penetration becomes possible with increasing temperature. Thermal desorption spectroscopy (TDS) measurements with pure H2 or D2 have been applied to study isotope adsorption. Further TDS experiments after exposure to an equimolar H2/D2 mixture allow to determine directly the selectivity of isotope separation by quantum sieving. IFP‐7 shows a very low selectivity not higher than S=2. The selectivity of the materials with the smallest pore aperture IFP‐4 has a constant value of S≈2 for different exposure times and pressures, which can be explained by the 1‐D channel structure. Due to the relatively small cavities between the apertures of IFP‐4 and IFP‐7, molecules in the channels cannot pass each other, which leads to a single‐file filling. Therefore, no time dependence is observed, since the quantum sieving effect occurs only at the outermost pore aperture, resulting in a low separation selectivity.
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Affiliation(s)
- Suvendu Sekhar Mondal
- Institut für Chemie, Anorganische Chemie, Universität Potsdam, Karl-Liebknecht-Straße 24-25, 14476, Potsdam, Germany
| | - Alex Kreuzer
- Modern Magnetic Systems, Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569, Stuttgart
| | - Karsten Behrens
- Institut für Chemie, Anorganische Chemie, Universität Potsdam, Karl-Liebknecht-Straße 24-25, 14476, Potsdam, Germany
| | - Gisela Schütz
- Modern Magnetic Systems, Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569, Stuttgart
| | - Hans-Jürgen Holdt
- Institut für Chemie, Anorganische Chemie, Universität Potsdam, Karl-Liebknecht-Straße 24-25, 14476, Potsdam, Germany
| | - Michael Hirscher
- Modern Magnetic Systems, Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569, Stuttgart
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32
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Sluka V, Schneider T, Gallardo RA, Kákay A, Weigand M, Warnatz T, Mattheis R, Roldán-Molina A, Landeros P, Tiberkevich V, Slavin A, Schütz G, Erbe A, Deac A, Lindner J, Raabe J, Fassbender J, Wintz S. Emission and propagation of 1D and 2D spin waves with nanoscale wavelengths in anisotropic spin textures. Nat Nanotechnol 2019; 14:328-333. [PMID: 30804478 DOI: 10.1038/s41565-019-0383-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 01/21/2019] [Indexed: 05/26/2023]
Abstract
Spin waves offer intriguing perspectives for computing and signal processing, because their damping can be lower than the ohmic losses in conventional complementary metal-oxide-semiconductor (CMOS) circuits. Magnetic domain walls show considerable potential as magnonic waveguides for on-chip control of the spatial extent and propagation of spin waves. However, low-loss guidance of spin waves with nanoscale wavelengths and around angled tracks remains to be shown. Here, we demonstrate spin wave control using natural anisotropic features of magnetic order in an interlayer exchange-coupled ferromagnetic bilayer. We employ scanning transmission X-ray microscopy to image the generation of spin waves and their propagation across distances exceeding multiples of the wavelength. Spin waves propagate in extended planar geometries as well as along straight or curved one-dimensional domain walls. We observe wavelengths between 1 μm and 150 nm, with excitation frequencies ranging from 250 MHz to 3 GHz. Our results show routes towards the practical implementation of magnonic waveguides in the form of domain walls in future spin wave logic and computational circuits.
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Affiliation(s)
- Volker Sluka
- Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany.
| | | | - Rodolfo A Gallardo
- Universidad Técnica Federico Santa María, Valparaíso, Chile
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), Santiago, Chile
| | - Attila Kákay
- Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
| | - Markus Weigand
- Max-Planck-Institut für Intelligente Systeme, Stuttgart, Germany
| | - Tobias Warnatz
- Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
- Uppsala Universitet, Uppsala, Sweden
| | - Roland Mattheis
- Leibniz Institut für Photonische Technologien, Jena, Germany
| | | | - Pedro Landeros
- Universidad Técnica Federico Santa María, Valparaíso, Chile
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), Santiago, Chile
| | | | | | - Gisela Schütz
- Max-Planck-Institut für Intelligente Systeme, Stuttgart, Germany
| | - Artur Erbe
- Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
| | - Alina Deac
- Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
| | | | - Jörg Raabe
- Paul Scherrer Institut, Villigen, PSI, Switzerland
| | - Jürgen Fassbender
- Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
- Technische Universität Dresden, Dresden, Germany
| | - Sebastian Wintz
- Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany.
- Paul Scherrer Institut, Villigen, PSI, Switzerland.
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33
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Li W, Bykova I, Zhang S, Yu G, Tomasello R, Carpentieri M, Liu Y, Guang Y, Gräfe J, Weigand M, Burn DM, van der Laan G, Hesjedal T, Yan Z, Feng J, Wan C, Wei J, Wang X, Zhang X, Xu H, Guo C, Wei H, Finocchio G, Han X, Schütz G. Anatomy of Skyrmionic Textures in Magnetic Multilayers. Adv Mater 2019; 31:e1807683. [PMID: 30735264 DOI: 10.1002/adma.201807683] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 01/28/2019] [Indexed: 06/09/2023]
Abstract
Room temperature magnetic skyrmions in magnetic multilayers are considered as information carriers for future spintronic applications. Currently, a detailed understanding of the skyrmion stabilization mechanisms is still lacking in these systems. To gain more insight, it is first and foremost essential to determine the full real-space spin configuration. Here, two advanced X-ray techniques are applied, based on magnetic circular dichroism, to investigate the spin textures of skyrmions in [Ta/CoFeB/MgO]n multilayers. First, by using ptychography, a high-resolution diffraction imaging technique, the 2D out-of-plane spin profile of skyrmions with a spatial resolution of 10 nm is determined. Second, by performing circular dichroism in resonant elastic X-ray scattering, it is demonstrated that the chirality of the magnetic structure undergoes a depth-dependent evolution. This suggests that the skyrmion structure is a complex 3D structure rather than an identical planar texture throughout the layer stack. The analyses of the spin textures confirm the theoretical predictions that the dipole-dipole interactions together with the external magnetic field play an important role in stabilizing sub-100 nm diameter skyrmions and the hybrid structure of the skyrmion domain wall. This combined X-ray-based approach opens the door for in-depth studies of magnetic skyrmion systems, which allows for precise engineering of optimized skyrmion heterostructures.
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Affiliation(s)
- Wenjing Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Iuliia Bykova
- Max Planck Institute for Intelligent Systems, Heisenbergstraße 3, 70569, Stuttgart, Germany
| | - Shilei Zhang
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford, OX1 3PU, UK
| | - Guoqiang Yu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Riccardo Tomasello
- Institute of Applied and Computational Mathematics, FORTH, GR-70013, Heraklion-Crete, Greece
| | - Mario Carpentieri
- Department of Electrical and Information Engineering, Polytechnic University of Bari, Bari, 70125, Italy
| | - Yizhou Liu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Yao Guang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Joachim Gräfe
- Max Planck Institute for Intelligent Systems, Heisenbergstraße 3, 70569, Stuttgart, Germany
| | - Markus Weigand
- Max Planck Institute for Intelligent Systems, Heisenbergstraße 3, 70569, Stuttgart, Germany
| | - David M Burn
- Magnetic Spectroscopy Group, Diamond Light Source, Didcot, OX11 0DE, UK
| | | | - Thorsten Hesjedal
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford, OX1 3PU, UK
| | - Zhengren Yan
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Jiafeng Feng
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Caihua Wan
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Jinwu Wei
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Xiao Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Xiaomin Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Hongjun Xu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Chenyang Guo
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Hongxiang Wei
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Giovanni Finocchio
- Department of Mathematical and Computer Sciences, Physical Sciences and Earth Sciences, University of Messina, Messina, 98166, Italy
| | - Xiufeng Han
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Gisela Schütz
- Max Planck Institute for Intelligent Systems, Heisenbergstraße 3, 70569, Stuttgart, Germany
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34
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Dieterle G, Förster J, Stoll H, Semisalova AS, Finizio S, Gangwar A, Weigand M, Noske M, Fähnle M, Bykova I, Gräfe J, Bozhko DA, Musiienko-Shmarova HY, Tiberkevich V, Slavin AN, Back CH, Raabe J, Schütz G, Wintz S. Coherent Excitation of Heterosymmetric Spin Waves with Ultrashort Wavelengths. Phys Rev Lett 2019; 122:117202. [PMID: 30951356 DOI: 10.1103/physrevlett.122.117202] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Indexed: 06/09/2023]
Abstract
In the emerging field of magnonics, spin waves are foreseen as signal carriers for future spintronic information processing and communication devices, owing to both the very low power losses and a high device miniaturization potential predicted for short-wavelength spin waves. Yet, the efficient excitation and controlled propagation of nanoscale spin waves remains a severe challenge. Here, we report the observation of high-amplitude, ultrashort dipole-exchange spin waves (down to 80 nm wavelength at 10 GHz frequency) in a ferromagnetic single layer system, coherently excited by the driven dynamics of a spin vortex core. We used time-resolved x-ray microscopy to directly image such propagating spin waves and their excitation over a wide range of frequencies. By further analysis, we found that these waves exhibit a heterosymmetric mode profile, involving regions with anti-Larmor precession sense and purely linear magnetic oscillation. In particular, this mode profile consists of dynamic vortices with laterally alternating helicity, leading to a partial magnetic flux closure over the film thickness, which is explained by a strong and unexpected mode hybridization. This spin-wave phenomenon observed is a general effect inherent to the dynamics of sufficiently thick ferromagnetic single layer films, independent of the specific excitation method employed.
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Affiliation(s)
- G Dieterle
- Max-Planck-Institut für Intelligente Systeme, 70569 Stuttgart, Germany
| | - J Förster
- Max-Planck-Institut für Intelligente Systeme, 70569 Stuttgart, Germany
| | - H Stoll
- Max-Planck-Institut für Intelligente Systeme, 70569 Stuttgart, Germany
- Johannes Gutenberg-Universität Mainz, 55128 Mainz, Germany
| | - A S Semisalova
- Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
| | - S Finizio
- Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - A Gangwar
- Universität Regensburg, 93053 Regensburg, Germany
| | - M Weigand
- Max-Planck-Institut für Intelligente Systeme, 70569 Stuttgart, Germany
| | - M Noske
- Max-Planck-Institut für Intelligente Systeme, 70569 Stuttgart, Germany
| | - M Fähnle
- Max-Planck-Institut für Intelligente Systeme, 70569 Stuttgart, Germany
| | - I Bykova
- Max-Planck-Institut für Intelligente Systeme, 70569 Stuttgart, Germany
| | - J Gräfe
- Max-Planck-Institut für Intelligente Systeme, 70569 Stuttgart, Germany
| | - D A Bozhko
- Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany
| | | | | | - A N Slavin
- Oakland University, Rochester, Michigan 48309, USA
| | - C H Back
- Universität Regensburg, 93053 Regensburg, Germany
| | - J Raabe
- Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - G Schütz
- Max-Planck-Institut für Intelligente Systeme, 70569 Stuttgart, Germany
| | - S Wintz
- Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
- Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
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35
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Lemesh I, Litzius K, Böttcher M, Bassirian P, Kerber N, Heinze D, Zázvorka J, Büttner F, Caretta L, Mann M, Weigand M, Finizio S, Raabe J, Im MY, Stoll H, Schütz G, Dupé B, Kläui M, Beach GSD. Current-Induced Skyrmion Generation through Morphological Thermal Transitions in Chiral Ferromagnetic Heterostructures. Adv Mater 2018; 30:e1805461. [PMID: 30368960 DOI: 10.1002/adma.201805461] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Indexed: 06/08/2023]
Abstract
Magnetic skyrmions promise breakthroughs in future memory and computing devices due to their inherent stability and small size. Their creation and current driven motion have been recently observed at room temperature, but the key mechanisms of their formation are not yet well-understood. Here it is shown that in heavy metal/ferromagnet heterostructures, pulsed currents can drive morphological transitions between labyrinth-like, stripe-like, and skyrmionic states. Using high-resolution X-ray microscopy, the spin texture evolution with temperature and magnetic field is imaged and it is demonstrated that with transient Joule heating, topological charges can be injected into the system, driving it across the stripe-skyrmion boundary. The observations are explained through atomistic spin dynamic and micromagnetic simulations that reveal a crossover to a global skyrmionic ground state above a threshold magnetic field, which is found to decrease with increasing temperature. It is demonstrated how by tuning the phase stability, one can reliably generate skyrmions by short current pulses and stabilize them at zero field, providing new means to create and manipulate spin textures in engineered chiral ferromagnets.
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Affiliation(s)
- Ivan Lemesh
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Kai Litzius
- Institute of Physics, Johannes Gutenberg-University Mainz, 55099, Mainz, Germany
- Graduate School of Excellence Materials Science in Mainz, 55128, Mainz, Germany
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - Marie Böttcher
- Institute of Physics, Johannes Gutenberg-University Mainz, 55099, Mainz, Germany
| | - Pedram Bassirian
- Institute of Physics, Johannes Gutenberg-University Mainz, 55099, Mainz, Germany
| | - Nico Kerber
- Institute of Physics, Johannes Gutenberg-University Mainz, 55099, Mainz, Germany
| | - Daniel Heinze
- Institute of Physics, Johannes Gutenberg-University Mainz, 55099, Mainz, Germany
| | - Jakub Zázvorka
- Institute of Physics, Johannes Gutenberg-University Mainz, 55099, Mainz, Germany
| | - Felix Büttner
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Lucas Caretta
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Maxwell Mann
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Markus Weigand
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - Simone Finizio
- Swiss Light Source, Paul Scherrer Institut, Villigen, PSI CH-5232, Switzerland
| | - Jörg Raabe
- Swiss Light Source, Paul Scherrer Institut, Villigen, PSI CH-5232, Switzerland
| | - Mi-Young Im
- Center for X-ray Optics, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Emerging Materials Science, DGIST, Daegu, 42988, Republic of Korea
- School of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Hermann Stoll
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - Gisela Schütz
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - Bertrand Dupé
- Institute of Physics, Johannes Gutenberg-University Mainz, 55099, Mainz, Germany
| | - Mathias Kläui
- Institute of Physics, Johannes Gutenberg-University Mainz, 55099, Mainz, Germany
- Graduate School of Excellence Materials Science in Mainz, 55128, Mainz, Germany
| | - Geoffrey S D Beach
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
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36
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Santomauro G, Singh AV, Park B, Mohammadrahimi M, Erkoc P, Goering E, Schütz G, Sitti M, Bill J. Incorporation of Terbium into a Microalga Leads to Magnetotactic Swimmers. ACTA ACUST UNITED AC 2018. [DOI: 10.1002/adbi.201800039] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Giulia Santomauro
- Institute for Materials ScienceUniversity of Stuttgart 70569 Stuttgart Germany
| | - Ajay Vikram Singh
- Physical Intelligence DepartmentMax Planck Institute for Intelligent Systems 70569 Stuttgart Germany
| | - Byung‐Wook Park
- Department of Civil/Environmental & Chemical EngineeringYoungstown State University Youngstown OH 44555 USA
| | | | - Pelin Erkoc
- Physical Intelligence DepartmentMax Planck Institute for Intelligent Systems 70569 Stuttgart Germany
| | - Eberhard Goering
- Modern Magnetic Systems DepartmentMax Planck Institute for Intelligent Systems 70569 Stuttgart Germany
| | - Gisela Schütz
- Modern Magnetic Systems DepartmentMax Planck Institute for Intelligent Systems 70569 Stuttgart Germany
| | - Metin Sitti
- Physical Intelligence DepartmentMax Planck Institute for Intelligent Systems 70569 Stuttgart Germany
| | - Joachim Bill
- Institute for Materials ScienceUniversity of Stuttgart 70569 Stuttgart Germany
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37
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Sanli UT, Jiao C, Baluktsian M, Grévent C, Hahn K, Wang Y, Srot V, Richter G, Bykova I, Weigand M, Schütz G, Keskinbora K. 3D Nanofabrication of High-Resolution Multilayer Fresnel Zone Plates. Adv Sci (Weinh) 2018; 5:1800346. [PMID: 30250789 PMCID: PMC6145245 DOI: 10.1002/advs.201800346] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 05/03/2018] [Indexed: 05/22/2023]
Abstract
Focusing X-rays to single nanometer dimensions is impeded by the lack of high-quality, high-resolution optics. Challenges in fabricating high aspect ratio 3D nanostructures limit the quality and the resolution. Multilayer zone plates target this challenge by offering virtually unlimited and freely selectable aspect ratios. Here, a full-ceramic zone plate is fabricated via atomic layer deposition of multilayers over optical quality glass fibers and subsequent focused ion beam slicing. The quality of the multilayers is confirmed up to an aspect ratio of 500 with zones as thin as 25 nm. Focusing performance of the fabricated zone plate is tested toward the high-energy limit of a soft X-ray scanning transmission microscope, achieving a 15 nm half-pitch cut-off resolution. Sources of adverse influences are identified, and effective routes for improving the zone plate performance are elaborated, paving a clear path toward using multilayer zone plates in high-energy X-ray microscopy. Finally, a new fabrication concept is introduced for making zone plates with precisely tilted zones, targeting even higher resolutions.
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Affiliation(s)
- Umut Tunca Sanli
- Modern Magnetic SystemsMax Planck Institute for Intelligent SystemsStuttgart70569Germany
| | - Chengge Jiao
- Thermo Fisher Scientific5651 GGEindhovenThe Netherlands
| | - Margarita Baluktsian
- Modern Magnetic SystemsMax Planck Institute for Intelligent SystemsStuttgart70569Germany
| | - Corinne Grévent
- Modern Magnetic SystemsMax Planck Institute for Intelligent SystemsStuttgart70569Germany
| | - Kersten Hahn
- Stuttgart Center for Electron MicroscopyMax Planck Institute for Solid State ResearchStuttgart70569Germany
| | - Yi Wang
- Stuttgart Center for Electron MicroscopyMax Planck Institute for Solid State ResearchStuttgart70569Germany
| | - Vesna Srot
- Stuttgart Center for Electron MicroscopyMax Planck Institute for Solid State ResearchStuttgart70569Germany
| | - Gunther Richter
- Modern Magnetic SystemsMax Planck Institute for Intelligent SystemsStuttgart70569Germany
| | - Iuliia Bykova
- Modern Magnetic SystemsMax Planck Institute for Intelligent SystemsStuttgart70569Germany
| | - Markus Weigand
- Modern Magnetic SystemsMax Planck Institute for Intelligent SystemsStuttgart70569Germany
| | - Gisela Schütz
- Modern Magnetic SystemsMax Planck Institute for Intelligent SystemsStuttgart70569Germany
| | - Kahraman Keskinbora
- Modern Magnetic SystemsMax Planck Institute for Intelligent SystemsStuttgart70569Germany
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38
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Keskinbora K, Sanli UT, Baluktsian M, Grévent C, Weigand M, Schütz G. High-throughput synthesis of modified Fresnel zone plate arrays via ion beam lithography. Beilstein J Nanotechnol 2018; 9:2049-2056. [PMID: 30116695 PMCID: PMC6071703 DOI: 10.3762/bjnano.9.194] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 07/13/2018] [Indexed: 06/08/2023]
Abstract
Fresnel zone plates (FZP) are diffractive photonic devices used for high-resolution imaging and lithography at short wavelengths. Their fabrication requires nano-machining capabilities with exceptional precision and strict tolerances such as those enabled by modern lithography methods. In particular, ion beam lithography (IBL) is a noteworthy method thanks to its robust direct writing/milling capability. IBL allows for rapid prototyping of high-resolution FZPs that can be used for high-resolution imaging at soft X-ray energies. Here, we discuss improvements in the process enabling us to write zones down to 15 nm in width, achieving an effective outermost zone width of 30 nm. With a 35% reduction in process time and an increase in resolution by 26% compared to our previous results, we were able to resolve 21 nm features of a test sample using the FZP. The new process conditions are then applied for fabrication of large arrays of high-resolution zone plates. Results show that relatively large areas can be decorated with nanostructured devices via IBL by using multipurpose SEM/FIB instruments with potential applications in FEL focusing, extreme UV and soft X-ray lithography and as wavefront sensing devices for beam diagnostics.
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Affiliation(s)
- Kahraman Keskinbora
- Max Planck Institute for Intelligent Systems, Heisenbergstrasse 3, 70569 Stuttgart, Germany
| | - Umut Tunca Sanli
- Max Planck Institute for Intelligent Systems, Heisenbergstrasse 3, 70569 Stuttgart, Germany
| | - Margarita Baluktsian
- Max Planck Institute for Intelligent Systems, Heisenbergstrasse 3, 70569 Stuttgart, Germany
| | - Corinne Grévent
- Max Planck Institute for Intelligent Systems, Heisenbergstrasse 3, 70569 Stuttgart, Germany
| | - Markus Weigand
- Max Planck Institute for Intelligent Systems, Heisenbergstrasse 3, 70569 Stuttgart, Germany
| | - Gisela Schütz
- Max Planck Institute for Intelligent Systems, Heisenbergstrasse 3, 70569 Stuttgart, Germany
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39
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Sanli UT, Ceylan H, Bykova I, Weigand M, Sitti M, Schütz G, Keskinbora K. 3D Nanoprinted Plastic Kinoform X-Ray Optics. Adv Mater 2018; 30:e1802503. [PMID: 30039537 DOI: 10.1002/adma.201802503] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 06/11/2018] [Indexed: 06/08/2023]
Abstract
High-performance focusing of X-rays requires the realization of very challenging 3D geometries with nanoscale features, sub-millimeter-scale apertures, and high aspect ratios. A particularly difficult structure is the profile of an ideal zone plate called a kinoform, which is manufactured in nonideal approximated patterns, nonetheless requires complicated multistep fabrication processes. Here, 3D fabrication of high-performance kinoforms with unprecedented aspect ratios out of low-loss plastics using femtosecond two-photon 3D nanoprinting is presented. A thorough characterization of the 3D-printed kinoforms using direct soft X-ray imaging and ptychography demonstrates superior performance with an efficiency reaching up to 20%. An extended concept is proposed for on-chip integration of various X-ray optics toward high-fidelity control of X-ray wavefronts and ultimate efficiencies even for harder X-rays. Initial results establish new, advanced focusing optics for both synchrotron and laboratory sources for a large variety of X-ray techniques and applications ranging from materials science to medicine.
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Affiliation(s)
- Umut T Sanli
- Modern Magnetic Systems Department, Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - Hakan Ceylan
- Physical Intelligence Department, Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - Iuliia Bykova
- Modern Magnetic Systems Department, Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - Markus Weigand
- Modern Magnetic Systems Department, Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - Metin Sitti
- Physical Intelligence Department, Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - Gisela Schütz
- Modern Magnetic Systems Department, Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - Kahraman Keskinbora
- Modern Magnetic Systems Department, Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
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40
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Abstract
Janus monolayers have long been captivated as a popular notion for breaking in-plane and out-of-plane structural symmetry. Originated from chemistry and materials science, the concept of Janus functions have been recently extended to ultrathin metasurfaces by arranging meta-atoms asymmetrically with respect to the propagation or polarization direction of the incident light. However, such metasurfaces are intrinsically static and the information they carry can be straightforwardly decrypted by scanning the incident light directions and polarization states once the devices are fabricated. In this Letter, we present a dynamic Janus metasurface scheme in the visible spectral region. In each super unit cell, three plasmonic pixels are categorized into two sets. One set contains a magnesium nanorod and a gold nanorod that are orthogonally oriented with respect to each other, working as counter pixels. The other set only contains a magnesium nanorod. The effective pixels on the Janus metasurface can be reversibly regulated by hydrogenation/dehydrogenation of the magnesium nanorods. Such dynamic controllability at visible frequencies allows for flat optical elements with novel functionalities including beam steering, bifocal lensing, holographic encryption, and dual optical function switching.
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Affiliation(s)
- Ping Yu
- Max Planck Institute for Intelligent Systems , Heisenbergstrasse 3 , 70569 Stuttgart , Germany
| | - Jianxiong Li
- Max Planck Institute for Intelligent Systems , Heisenbergstrasse 3 , 70569 Stuttgart , Germany
| | - Shuang Zhang
- School of Physics and Astronomy , University of Birmingham , Birmingham B15 2TT , United Kingdom
| | - Zhongwei Jin
- Department of Electrical and Computer Engineering , National University of Singapore , 4 Engineering Drive 3 , Singapore 117583 , Singapore
| | - Gisela Schütz
- Max Planck Institute for Intelligent Systems , Heisenbergstrasse 3 , 70569 Stuttgart , Germany
| | - Cheng-Wei Qiu
- Department of Electrical and Computer Engineering , National University of Singapore , 4 Engineering Drive 3 , Singapore 117583 , Singapore
- NUS Suzhou Research Institute (NUSRI) , Suzhou Industrial Park , Suzhou 215123 , China
| | - Michael Hirscher
- Max Planck Institute for Intelligent Systems , Heisenbergstrasse 3 , 70569 Stuttgart , Germany
| | - Na Liu
- Max Planck Institute for Intelligent Systems , Heisenbergstrasse 3 , 70569 Stuttgart , Germany
- Kirchhoff Institute for Physics , University of Heidelberg , Im Neuenheimer Feld 227 , 69120 Heidelberg , Germany
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41
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Chung S, Le QT, Ahlberg M, Awad AA, Weigand M, Bykova I, Khymyn R, Dvornik M, Mazraati H, Houshang A, Jiang S, Nguyen TNA, Goering E, Schütz G, Gräfe J, Åkerman J. Direct Observation of Zhang-Li Torque Expansion of Magnetic Droplet Solitons. Phys Rev Lett 2018; 120:217204. [PMID: 29883139 DOI: 10.1103/physrevlett.120.217204] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Indexed: 06/08/2023]
Abstract
Magnetic droplets are nontopological dynamical solitons that can be nucleated in nanocontact based spin torque nano-oscillators (STNOs) with perpendicular magnetic anisotropy free layers. While theory predicts that the droplet should be of the same size as the nanocontact, its inherent drift instability has thwarted attempts at observing it directly using microscopy techniques. Here, we demonstrate highly stable magnetic droplets in all-perpendicular STNOs and present the first detailed droplet images using scanning transmission X-ray microscopy. In contrast to theoretical predictions, we find that the droplet diameter is about twice as large as the nanocontact. By extending the original droplet theory to properly account for the lateral current spread underneath the nanocontact, we show that the large discrepancy primarily arises from current-in-plane Zhang-Li torque adding an outward pressure on the droplet perimeter. Electrical measurements on droplets nucleated using a reversed current in the antiparallel state corroborate this picture.
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Affiliation(s)
- Sunjae Chung
- Department of Physics, University of Gothenburg, 412 96 Gothenburg, Sweden
- Department of Applied Physics, School of Engineering Sciences, KTH Royal Institute of Technology, 164 40 Kista, Sweden
- Department of Physics and Astronomy, Uppsala University, 751 20 Uppsala, Sweden
| | - Q Tuan Le
- Department of Physics, University of Gothenburg, 412 96 Gothenburg, Sweden
- Department of Applied Physics, School of Engineering Sciences, KTH Royal Institute of Technology, 164 40 Kista, Sweden
| | - Martina Ahlberg
- Department of Physics, University of Gothenburg, 412 96 Gothenburg, Sweden
- NanOsc AB, 164 40 Kista, Sweden
| | - Ahmad A Awad
- Department of Physics, University of Gothenburg, 412 96 Gothenburg, Sweden
- NanOsc AB, 164 40 Kista, Sweden
| | - Markus Weigand
- Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - Iuliia Bykova
- Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - Roman Khymyn
- Department of Physics, University of Gothenburg, 412 96 Gothenburg, Sweden
| | - Mykola Dvornik
- Department of Physics, University of Gothenburg, 412 96 Gothenburg, Sweden
| | - Hamid Mazraati
- Department of Applied Physics, School of Engineering Sciences, KTH Royal Institute of Technology, 164 40 Kista, Sweden
- NanOsc AB, 164 40 Kista, Sweden
| | - Afshin Houshang
- Department of Physics, University of Gothenburg, 412 96 Gothenburg, Sweden
- NanOsc AB, 164 40 Kista, Sweden
| | - Sheng Jiang
- Department of Applied Physics, School of Engineering Sciences, KTH Royal Institute of Technology, 164 40 Kista, Sweden
| | - T N Anh Nguyen
- Department of Physics, University of Gothenburg, 412 96 Gothenburg, Sweden
- Department of Applied Physics, School of Engineering Sciences, KTH Royal Institute of Technology, 164 40 Kista, Sweden
- Laboratory of Magnetism and Superconductivity, Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, 122300 Hanoi, Vietnam
| | - Eberhard Goering
- Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - Gisela Schütz
- Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - Joachim Gräfe
- Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - Johan Åkerman
- Department of Physics, University of Gothenburg, 412 96 Gothenburg, Sweden
- Department of Applied Physics, School of Engineering Sciences, KTH Royal Institute of Technology, 164 40 Kista, Sweden
- NanOsc AB, 164 40 Kista, Sweden
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42
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Weinrauch I, Savchenko I, Denysenko D, Souliou SM, Kim HH, Le Tacon M, Daemen LL, Cheng Y, Mavrandonakis A, Ramirez-Cuesta AJ, Volkmer D, Schütz G, Hirscher M, Heine T. Capture of heavy hydrogen isotopes in a metal-organic framework with active Cu(I) sites. Nat Commun 2017; 8:14496. [PMID: 28262794 PMCID: PMC5343471 DOI: 10.1038/ncomms14496] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 01/06/2017] [Indexed: 01/20/2023] Open
Abstract
The production of pure deuterium and the removal of tritium from nuclear waste are the key challenges in separation of light isotopes. Presently, the technological methods are extremely energy- and cost-intensive. Here we report the capture of heavy hydrogen isotopes from hydrogen gas by selective adsorption at Cu(I) sites in a metal-organic framework. At the strongly binding Cu(I) sites (32 kJ mol-1) nuclear quantum effects result in higher adsorption enthalpies of heavier isotopes. The capture mechanism takes place most efficiently at temperatures above 80 K, when an isotope exchange allows the preferential adsorption of heavy isotopologues from the gas phase. Large difference in adsorption enthalpy of 2.5 kJ mol-1 between D2 and H2 results in D2-over-H2 selectivity of 11 at 100 K, to the best of our knowledge the largest value known to date. Combination of thermal desorption spectroscopy, Raman measurements, inelastic neutron scattering and first principles calculations for H2/D2 mixtures allows the prediction of selectivities for tritium-containing isotopologues.
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Affiliation(s)
- I Weinrauch
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569 Stuttgart, Germany
| | - I Savchenko
- Jacobs University, School of Engineering and Science, Campus Ring 1, 28759 Bremen, Germany
| | - D Denysenko
- Augsburg University, Institute of Physics, Universitätsstr. 1, 86159 Augsburg, Germany
| | - S M Souliou
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569 Stuttgart, Germany
| | - H-H Kim
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569 Stuttgart, Germany
| | - M Le Tacon
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569 Stuttgart, Germany
| | - L L Daemen
- Oak Ridge National Laboratory, Spallation Neutron Source, PO Box 2008, MS6475, Oak Ridge, TN 37831-6471, USA
| | - Y Cheng
- Oak Ridge National Laboratory, Spallation Neutron Source, PO Box 2008, MS6475, Oak Ridge, TN 37831-6471, USA
| | - A Mavrandonakis
- Jacobs University, School of Engineering and Science, Campus Ring 1, 28759 Bremen, Germany
| | - A J Ramirez-Cuesta
- Oak Ridge National Laboratory, Spallation Neutron Source, PO Box 2008, MS6475, Oak Ridge, TN 37831-6471, USA
| | - D Volkmer
- Augsburg University, Institute of Physics, Universitätsstr. 1, 86159 Augsburg, Germany
| | - G Schütz
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569 Stuttgart, Germany
| | - M Hirscher
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569 Stuttgart, Germany
| | - T Heine
- Jacobs University, School of Engineering and Science, Campus Ring 1, 28759 Bremen, Germany.,Wilhelm-Ostwald-Institute of Physical and Theoretical Chemistry, Leipzig University, Linnéstr. 2, 04103 Leipzig, Germany
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43
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Bisig A, Akosa CA, Moon JH, Rhensius J, Moutafis C, von Bieren A, Heidler J, Kiliani G, Kammerer M, Curcic M, Weigand M, Tyliszczak T, Van Waeyenberge B, Stoll H, Schütz G, Lee KJ, Manchon A, Kläui M. Enhanced Nonadiabaticity in Vortex Cores due to the Emergent Hall Effect. Phys Rev Lett 2016; 117:277203. [PMID: 28084754 DOI: 10.1103/physrevlett.117.277203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Indexed: 06/06/2023]
Abstract
We present a combined theoretical and experimental study, investigating the origin of the enhanced nonadiabaticity of magnetic vortex cores. Scanning transmission x-ray microscopy is used to image the vortex core gyration dynamically to measure the nonadiabaticity with high precision, including a high confidence upper bound. We show theoretically, that the large nonadiabaticity parameter observed experimentally can be explained by the presence of local spin currents arising from a texture induced emergent Hall effect. This study demonstrates that the magnetic damping α and nonadiabaticity parameter β are very sensitive to the topology of the magnetic textures, resulting in an enhanced ratio (β/α>1) in magnetic vortex cores or Skyrmions.
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Affiliation(s)
- André Bisig
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
- Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
- Institute of Condensed Matter Physics, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
- Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
- Institut of Physics, Johannes Gutenberg University Mainz, 55099 Mainz, Germany
| | - Collins Ashu Akosa
- King Abdullah University of Science and Technology (KAUST), Physical Science and Engineering Division, Thuwal 23955-6900, Saudi Arabia
| | - Jung-Hwan Moon
- Department of Materials Science and Engineering, Korea University, Seoul 136-713, Korea
| | - Jan Rhensius
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
- Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Christoforos Moutafis
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
- Institute of Condensed Matter Physics, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
- Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Arndt von Bieren
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
- Institute of Condensed Matter Physics, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
- Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Jakoba Heidler
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
- Institute of Condensed Matter Physics, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
- Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Gillian Kiliani
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
| | - Matthias Kammerer
- Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - Michael Curcic
- Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - Markus Weigand
- Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - Tolek Tyliszczak
- Advanced Light Source, LBL, University of California, Berkeley, Berkeley, California 94720, USA
| | | | - Hermann Stoll
- Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - Gisela Schütz
- Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - Kyung-Jin Lee
- Department of Materials Science and Engineering, Korea University, Seoul 136-713, Korea
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 136-713, Korea
| | - Aurelien Manchon
- King Abdullah University of Science and Technology (KAUST), Physical Science and Engineering Division, Thuwal 23955-6900, Saudi Arabia
| | - Mathias Kläui
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
- Institute of Condensed Matter Physics, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
- Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
- Institut of Physics, Johannes Gutenberg University Mainz, 55099 Mainz, Germany
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Straumal BB, Protasova SG, Mazilkin AA, Goering E, Schütz G, Straumal PB, Baretzky B. Ferromagnetic behaviour of ZnO: the role of grain boundaries. Beilstein J Nanotechnol 2016; 7:1936-1947. [PMID: 28144542 PMCID: PMC5238656 DOI: 10.3762/bjnano.7.185] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 11/09/2016] [Indexed: 05/26/2023]
Abstract
The possibility to attain ferromagnetic properties in transparent semiconductor oxides such as ZnO is very promising for future spintronic applications. We demonstrate in this review that ferromagnetism is not an intrinsic property of the ZnO crystalline lattice but is that of ZnO/ZnO grain boundaries. If a ZnO polycrystal contains enough grain boundaries, it can transform into the ferromagnetic state even without doping with "magnetic atoms" such as Mn, Co, Fe or Ni. However, such doping facilitates the appearance of ferromagnetism in ZnO. It increases the saturation magnetisation and decreases the critical amount of grain boundaries needed for FM. A drastic increase of the total solubility of dopants in ZnO with decreasing grain size has been also observed. It is explained by the multilayer grain boundary segregation.
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Affiliation(s)
- Boris Borisovich Straumal
- Karlsruher Institut für Technologie, Institut für Nanotechnologie, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
- Institute of Solid State Physics, Russian Academy of Sciences, Ac. Ossipyan str. 2, 142432 Chernogolovka, Russia
- Max-Planck-Institut für Intelligente Systeme, Heisenbergstrasse 3, 70569 Stuttgart, Germany
- National University for Research and Technology “MISiS”, Leninsky prospect 4, 119991 Moscow, Russia
| | - Svetlana G Protasova
- Institute of Solid State Physics, Russian Academy of Sciences, Ac. Ossipyan str. 2, 142432 Chernogolovka, Russia
- Max-Planck-Institut für Intelligente Systeme, Heisenbergstrasse 3, 70569 Stuttgart, Germany
| | - Andrei A Mazilkin
- Karlsruher Institut für Technologie, Institut für Nanotechnologie, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
- Institute of Solid State Physics, Russian Academy of Sciences, Ac. Ossipyan str. 2, 142432 Chernogolovka, Russia
| | - Eberhard Goering
- Max-Planck-Institut für Intelligente Systeme, Heisenbergstrasse 3, 70569 Stuttgart, Germany
| | - Gisela Schütz
- Max-Planck-Institut für Intelligente Systeme, Heisenbergstrasse 3, 70569 Stuttgart, Germany
| | - Petr B Straumal
- National University for Research and Technology “MISiS”, Leninsky prospect 4, 119991 Moscow, Russia
- Institute of Metallurgy and Materials Science, Russian Academy of Sciences, Leninsky prospect 49, 117991 Moscow, Russia
| | - Brigitte Baretzky
- Karlsruher Institut für Technologie, Institut für Nanotechnologie, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
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Noske M, Stoll H, Fähnle M, Gangwar A, Woltersdorf G, Slavin A, Weigand M, Dieterle G, Förster J, Back CH, Schütz G. Three-dimensional Character of the Magnetization Dynamics in Magnetic Vortex Structures: Hybridization of Flexure Gyromodes with Spin Waves. Phys Rev Lett 2016; 117:037208. [PMID: 27472138 DOI: 10.1103/physrevlett.117.037208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Indexed: 06/06/2023]
Abstract
Three-dimensional linear spin-wave eigenmodes of a vortex-state Permalloy disk are studied by micromagnetic simulations based on the Landau-Lifshitz-Gilbert equation. The simulations confirm that the increase of the disk thickness leads to the appearance of additional exchange-dominated so-called gyrotropic flexure modes having nodes along the disk thickness, and eigenfrequencies that decrease when the thickness is increased. We observe the formation of a gap in the mode spectrum caused by the hybridization of the first flexure mode with one of the azimuthal spin-wave modes of the disk. A qualitative change of the transverse profile of this azimuthal mode is found, demonstrating that in a thick vortex-state disk the influence of the "transverse" and the "azimuthal" coordinates cannot be separated. The three-dimensional character of the eigenmodes is essential to explain the recently observed asymmetries in an experimentally obtained phase diagram of vortex-core reversal in relatively thick Permalloy disks.
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Affiliation(s)
- Matthias Noske
- Max Planck Institute for Intelligent Systems, Heisenbergstraße 3, 70569 Stuttgart, Germany
| | - Hermann Stoll
- Max Planck Institute for Intelligent Systems, Heisenbergstraße 3, 70569 Stuttgart, Germany
| | - Manfred Fähnle
- Max Planck Institute for Intelligent Systems, Heisenbergstraße 3, 70569 Stuttgart, Germany
| | - Ajay Gangwar
- Max Planck Institute for Intelligent Systems, Heisenbergstraße 3, 70569 Stuttgart, Germany
- University of Regensburg, Department of Physics, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Georg Woltersdorf
- Martin Luther University Halle-Wittenberg, Department of Physics, Von-Danckelmann-Platz 3, 06120 Halle, Germany
| | - Andrei Slavin
- Oakland University, Department of Physics, Rochester, Michigan 48309, USA
| | - Markus Weigand
- Max Planck Institute for Intelligent Systems, Heisenbergstraße 3, 70569 Stuttgart, Germany
| | - Georg Dieterle
- Max Planck Institute for Intelligent Systems, Heisenbergstraße 3, 70569 Stuttgart, Germany
| | - Johannes Förster
- Max Planck Institute for Intelligent Systems, Heisenbergstraße 3, 70569 Stuttgart, Germany
| | - Christian H Back
- University of Regensburg, Department of Physics, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Gisela Schütz
- Max Planck Institute for Intelligent Systems, Heisenbergstraße 3, 70569 Stuttgart, Germany
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Wiedwald U, Gräfe J, Lebecki KM, Skripnik M, Haering F, Schütz G, Ziemann P, Goering E, Nowak U. Magnetic switching of nanoscale antidot lattices. Beilstein J Nanotechnol 2016; 7:733-50. [PMID: 27335762 PMCID: PMC4901900 DOI: 10.3762/bjnano.7.65] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 04/30/2016] [Indexed: 06/06/2023]
Abstract
We investigate the rich magnetic switching properties of nanoscale antidot lattices in the 200 nm regime. In-plane magnetized Fe, Co, and Permalloy (Py) as well as out-of-plane magnetized GdFe antidot films are prepared by a modified nanosphere lithography allowing for non-close packed voids in a magnetic film. We present a magnetometry protocol based on magneto-optical Kerr microscopy elucidating the switching modes using first-order reversal curves. The combination of various magnetometry and magnetic microscopy techniques as well as micromagnetic simulations delivers a thorough understanding of the switching modes. While part of the investigations has been published before, we summarize these results and add significant new insights in the magnetism of exchange-coupled antidot lattices.
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Affiliation(s)
- Ulf Wiedwald
- Institute of Solid State Physics, Ulm University, Albert-Einstein-Allee 11, 89069 Ulm, Germany
- Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Lotharstr. 1, 47057 Duisburg, Germany
| | - Joachim Gräfe
- Max-Planck-Institute for Intelligent Systems, Heisenbergstr. 3, 70569 Stuttgart, Germany
| | - Kristof M Lebecki
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
- IT4Innovations Centre, VSB Technical University of Ostrava, Czech Republic
| | - Maxim Skripnik
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
| | - Felix Haering
- Institute of Solid State Physics, Ulm University, Albert-Einstein-Allee 11, 89069 Ulm, Germany
| | - Gisela Schütz
- Max-Planck-Institute for Intelligent Systems, Heisenbergstr. 3, 70569 Stuttgart, Germany
| | - Paul Ziemann
- Institute of Solid State Physics, Ulm University, Albert-Einstein-Allee 11, 89069 Ulm, Germany
| | - Eberhard Goering
- Max-Planck-Institute for Intelligent Systems, Heisenbergstr. 3, 70569 Stuttgart, Germany
| | - Ulrich Nowak
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
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Audehm P, Schmidt M, Brück S, Tietze T, Gräfe J, Macke S, Schütz G, Goering E. Pinned orbital moments - A new contribution to magnetic anisotropy. Sci Rep 2016; 6:25517. [PMID: 27151436 PMCID: PMC4858686 DOI: 10.1038/srep25517] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 04/15/2016] [Indexed: 11/19/2022] Open
Abstract
Reduced dimensionality and symmetry breaking at interfaces lead to unusual local magnetic configurations, such as glassy behavior, frustration or increased anisotropy. The interface between a ferromagnet and an antiferromagnet is such an example for enhanced symmetry breaking. Here we present detailed X-ray magnetic circular dichroism and X-ray resonant magnetic reflectometry investigations on the spectroscopic nature of uncompensated pinned magnetic moments in the antiferromagnetic layer of a typical exchange bias system. Unexpectedly, the pinned moments exhibit nearly pure orbital moment character. This strong orbital pinning mechanism has not been observed so far and is not discussed in literature regarding any theory for local magnetocrystalline anisotropy energies in magnetic systems. To verify this new phenomenon we investigated the effect at different temperatures. We provide a simple model discussing the observed pure orbital moments, based on rotatable spin magnetic moments and pinned orbital moments on the same atom. This unexpected observation leads to a concept for a new type of anisotropy energy.
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Affiliation(s)
- P Audehm
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, D-70569 Stuttgart, Germany
| | - M Schmidt
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, D-70569 Stuttgart, Germany
| | - S Brück
- Physikalisches Institut, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - T Tietze
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, D-70569 Stuttgart, Germany
| | - J Gräfe
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, D-70569 Stuttgart, Germany
| | - S Macke
- Quantum Matter Institute and Department of Physics and Astronomy University of British Columbia 2355 East Mall, Vancouver, V6T 1Z4, Canada.,Max Planck Institute for Solid State Research, Heisenbergstraße 1, D-70569, Stuttgart, Germany
| | - G Schütz
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, D-70569 Stuttgart, Germany
| | - E Goering
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, D-70569 Stuttgart, Germany
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Schütz G, Rembold A, Pooch A, Prochel H, Stibor A. Effective beam separation schemes for the measurement of the electric Aharonov–Bohm effect in an ion interferometer. Ultramicroscopy 2015; 158:65-73. [DOI: 10.1016/j.ultramic.2015.06.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Revised: 06/22/2015] [Accepted: 06/28/2015] [Indexed: 10/23/2022]
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Jeong HH, Mark AG, Lee TC, Son K, Chen W, Alarcón-Correa M, Kim I, Schütz G, Fischer P. Selectable Nanopattern Arrays for Nanolithographic Imprint and Etch-Mask Applications. Adv Sci (Weinh) 2015; 2:1500016. [PMID: 27980957 PMCID: PMC5115431 DOI: 10.1002/advs.201500016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Revised: 04/07/2015] [Indexed: 05/22/2023]
Abstract
A parallel nanolithographic patterning method is presented that can be used to obtain arrays of multifunctional nanoparticles. These patterns can simply be converted into a variety of secondary nanopatterns that are useful for nanolithographic imprint, plasmonic, and etch-mask applications.
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Affiliation(s)
- Hyeon-Ho Jeong
- Max Planck Institute for Intelligent Systems Heisenbergstr. 3 70569 Stuttgart Germany
| | - Andrew G Mark
- Max Planck Institute for Intelligent Systems Heisenbergstr. 3 70569 Stuttgart Germany
| | - Tung-Chun Lee
- Max Planck Institute for Intelligent Systems Heisenbergstr. 370569 Stuttgart Germany; Institute for Materials Discovery University College London Kathleen Lonsdale Building Gower Place London WC1E 6BT UK
| | - Kwanghyo Son
- Max Planck Institute for Intelligent Systems Heisenbergstr. 3 70569 Stuttgart Germany
| | - Wenwen Chen
- Max Planck Institute for Intelligent Systems Heisenbergstr. 370569 Stuttgart Germany; Department of Biophysical Chemistry University of Heidelberg INF 25369120 Heidelberg Germany
| | - Mariana Alarcón-Correa
- Max Planck Institute for Intelligent Systems Heisenbergstr. 370569 Stuttgart Germany; Institute for Physical Chemistry University of Stuttgart Pfaffenwaldring 5570569 Stuttgart Germany
| | - Insook Kim
- Max Planck Institute for Intelligent Systems Heisenbergstr. 370569 Stuttgart Germany; Institute for Physical Chemistry University of Stuttgart Pfaffenwaldring 5570569 Stuttgart Germany
| | - Gisela Schütz
- Max Planck Institute for Intelligent Systems Heisenbergstr. 3 70569 Stuttgart Germany
| | - Peer Fischer
- Max Planck Institute for Intelligent Systems Heisenbergstr. 370569 Stuttgart Germany; Institute for Physical Chemistry University of Stuttgart Pfaffenwaldring 5570569 Stuttgart Germany
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50
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Gräfe J, Haering F, Tietze T, Audehm P, Weigand M, Wiedwald U, Ziemann P, Gawroński P, Schütz G, Goering EJ. Perpendicular magnetisation from in-plane fields in nano-scaled antidot lattices. Nanotechnology 2015; 26:225203. [PMID: 25969389 DOI: 10.1088/0957-4484/26/22/225203] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Investigations of geometric frustrations in magnetic antidot lattices have led to the observation of interesting phenomena like spin-ice and magnetic monopoles. By using highly focused magneto-optical Kerr effect measurements and x-ray microscopy with magnetic contrast we deduce that geometrical frustration in these nanostructured thin film systems also leads to an out-of-plane magnetization from a purely in-plane applied magnetic field. For certain orientations of the antidot lattice, formation of perpendicular magnetic domains has been found with a size of several μm that may be used for an in-plane/out-of-plane transducer.
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Affiliation(s)
- Joachim Gräfe
- Max Planck Institute for Intelligent Systems, Stuttgart, Germany
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