1
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Girardi D, Finizio S, Donnelly C, Rubini G, Mayr S, Levati V, Cuccurullo S, Maspero F, Raabe J, Petti D, Albisetti E. Three-dimensional spin-wave dynamics, localization and interference in a synthetic antiferromagnet. Nat Commun 2024; 15:3057. [PMID: 38594233 PMCID: PMC11004151 DOI: 10.1038/s41467-024-47339-9] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 03/28/2024] [Indexed: 04/11/2024] Open
Abstract
Spin waves are collective perturbations in the orientation of the magnetic moments in magnetically ordered materials. Their rich phenomenology is intrinsically three-dimensional; however, the three-dimensional imaging of spin waves has so far not been possible. Here, we image the three-dimensional dynamics of spin waves excited in a synthetic antiferromagnet, with nanoscale spatial resolution and sub-ns temporal resolution, using time-resolved magnetic laminography. In this way, we map the distribution of the spin-wave modes throughout the volume of the structure, revealing unexpected depth-dependent profiles originating from the interlayer dipolar interaction. We experimentally demonstrate the existence of complex three-dimensional interference patterns and analyze them via micromagnetic modelling. We find that these patterns are generated by the superposition of spin waves with non-uniform amplitude profiles, and that their features can be controlled by tuning the composition and structure of the magnetic system. Our results open unforeseen possibilities for the study and manipulation of complex spin-wave modes within nanostructures and magnonic devices.
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Affiliation(s)
- Davide Girardi
- Dipartimento di Fisica, Politecnico di Milano; Piazza Leonardo da Vinci 32, Milano, 20133, Italy
| | - Simone Finizio
- Swiss Light Source, Paul Scherrer Institut; Forschungsstrasse 111 5232 PSI, Villigen, Switzerland
| | - Claire Donnelly
- Max Planck Institute for Chemical Physics of Solids; Nöthnitzer Str. 40, 01187, Dresden, Germany
- International Institute for Sustainability with Knotted Chiral Meta Matter (WPI-SKCM2), Hiroshima University, Hiroshima, 739-8526, Japan
| | - Guglielmo Rubini
- Dipartimento di Fisica, Politecnico di Milano; Piazza Leonardo da Vinci 32, Milano, 20133, Italy
| | - Sina Mayr
- Swiss Light Source, Paul Scherrer Institut; Forschungsstrasse 111 5232 PSI, Villigen, Switzerland
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, 8093, Zurich, Switzerland
| | - Valerio Levati
- Dipartimento di Fisica, Politecnico di Milano; Piazza Leonardo da Vinci 32, Milano, 20133, Italy
| | - Simone Cuccurullo
- Dipartimento di Fisica, Politecnico di Milano; Piazza Leonardo da Vinci 32, Milano, 20133, Italy
| | - Federico Maspero
- Dipartimento di Fisica, Politecnico di Milano; Piazza Leonardo da Vinci 32, Milano, 20133, Italy
| | - Jörg Raabe
- Swiss Light Source, Paul Scherrer Institut; Forschungsstrasse 111 5232 PSI, Villigen, Switzerland
| | - Daniela Petti
- Dipartimento di Fisica, Politecnico di Milano; Piazza Leonardo da Vinci 32, Milano, 20133, Italy.
| | - Edoardo Albisetti
- Dipartimento di Fisica, Politecnico di Milano; Piazza Leonardo da Vinci 32, Milano, 20133, Italy.
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2
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Butcher TA, Phillips NW, Chiu CC, Wei CC, Ho SZ, Chen YC, Fröjdh E, Baruffaldi F, Carulla M, Zhang J, Bergamaschi A, Vaz CAF, Kleibert A, Finizio S, Yang JC, Huang SW, Raabe J. Ptychographic Nanoscale Imaging of the Magnetoelectric Coupling in Freestanding BiFeO 3. Adv Mater 2024:e2311157. [PMID: 38402421 DOI: 10.1002/adma.202311157] [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: 10/24/2023] [Revised: 12/23/2023] [Indexed: 02/26/2024]
Abstract
Understanding the magnetic and ferroelectric ordering of magnetoelectric multiferroic materials at the nanoscale necessitates a versatile imaging method with high spatial resolution. Here, soft X-ray ptychography is employed to simultaneously image the ferroelectric and antiferromagnetic domains in an 80 nm thin freestanding film of the room-temperature multiferroic BiFeO3 (BFO). The antiferromagnetic spin cycloid of period 64 nm is resolved by reconstructing the corresponding resonant elastic X-ray scattering in real space and visualized together with mosaic-like ferroelectric domains in a linear dichroic contrast image at the Fe L3 edge. The measurements reveal a near perfect coupling between the antiferromagnetic and ferroelectric ordering by which the propagation direction of the spin cycloid is locked orthogonally to the ferroelectric polarization. In addition, the study evinces both a preference for in-plane propagation of the spin cycloid and changes of the ferroelectric polarization by 71° between multiferroic domains in the epitaxial strain-free, freestanding BFO film. The results provide a direct visualization of the strong magnetoelectric coupling in BFO and of its fine multiferroic domain structure, emphasizing the potential of ptychographic imaging for the study of multiferroics and non-collinear magnetic materials with soft X-rays.
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Affiliation(s)
- Tim A Butcher
- Paul Scherrer Institut, Villigen PSI, 5232, Switzerland
| | | | - Chun-Chien Chiu
- Department of Physics, National Cheng Kung University, Tainan, 70101, Taiwan
| | - Chia-Chun Wei
- Department of Physics, National Cheng Kung University, Tainan, 70101, Taiwan
| | - Sheng-Zhu Ho
- Department of Physics, National Cheng Kung University, Tainan, 70101, Taiwan
| | - Yi-Chun Chen
- Department of Physics, National Cheng Kung University, Tainan, 70101, Taiwan
| | - Erik Fröjdh
- Paul Scherrer Institut, Villigen PSI, 5232, Switzerland
| | | | - Maria Carulla
- Paul Scherrer Institut, Villigen PSI, 5232, Switzerland
| | - Jiaguo Zhang
- Paul Scherrer Institut, Villigen PSI, 5232, Switzerland
| | | | | | | | | | - Jan-Chi Yang
- Department of Physics, National Cheng Kung University, Tainan, 70101, Taiwan
- Center for Quantum Frontiers of Research & Technology (QFort), National Cheng Kung University, Tainan, 70101, Taiwan
| | | | - Jörg Raabe
- Paul Scherrer Institut, Villigen PSI, 5232, Switzerland
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3
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Jani H, Harrison J, Hooda S, Prakash S, Nandi P, Hu J, Zeng Z, Lin JC, Godfrey C, Omar GJ, Butcher TA, Raabe J, Finizio S, Thean AVY, Ariando A, Radaelli PG. Spatially reconfigurable antiferromagnetic states in topologically rich free-standing nanomembranes. Nat Mater 2024:10.1038/s41563-024-01806-2. [PMID: 38374414 DOI: 10.1038/s41563-024-01806-2] [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: 02/05/2023] [Accepted: 01/11/2024] [Indexed: 02/21/2024]
Abstract
Antiferromagnets hosting real-space topological textures are promising platforms to model fundamental ultrafast phenomena and explore spintronics. However, they have only been epitaxially fabricated on specific symmetry-matched substrates, thereby preserving their intrinsic magneto-crystalline order. This curtails their integration with dissimilar supports, restricting the scope of fundamental and applied investigations. Here we circumvent this limitation by designing detachable crystalline antiferromagnetic nanomembranes of α-Fe2O3. First, we show-via transmission-based antiferromagnetic vector mapping-that flat nanomembranes host a spin-reorientation transition and rich topological phenomenology. Second, we exploit their extreme flexibility to demonstrate the reconfiguration of antiferromagnetic states across three-dimensional membrane folds resulting from flexure-induced strains. Finally, we combine these developments using a controlled manipulator to realize the strain-driven non-thermal generation of topological textures at room temperature. The integration of such free-standing antiferromagnetic layers with flat/curved nanostructures could enable spin texture designs via magnetoelastic/geometric effects in the quasi-static and dynamical regimes, opening new explorations into curvilinear antiferromagnetism and unconventional computing.
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Affiliation(s)
- Hariom Jani
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, UK.
- Department of Physics, National University of Singapore, Singapore, Singapore.
| | - Jack Harrison
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, UK
| | - Sonu Hooda
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Saurav Prakash
- Department of Physics, National University of Singapore, Singapore, Singapore
| | - Proloy Nandi
- Department of Physics, National University of Singapore, Singapore, Singapore
| | - Junxiong Hu
- Department of Physics, National University of Singapore, Singapore, Singapore.
| | - Zhiyang Zeng
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, UK
| | - Jheng-Cyuan Lin
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, UK
| | - Charles Godfrey
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, UK
| | - Ganesh Ji Omar
- Department of Physics, National University of Singapore, Singapore, Singapore
| | - Tim A Butcher
- Swiss Light Source, Paul Scherrer Institut, Villigen, Switzerland
| | - Jörg Raabe
- Swiss Light Source, Paul Scherrer Institut, Villigen, Switzerland
| | - Simone Finizio
- Swiss Light Source, Paul Scherrer Institut, Villigen, Switzerland.
| | - Aaron Voon-Yew Thean
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
- Integrative Sciences and Engineering Programme, National University of Singapore, Singapore, Singapore
| | - A Ariando
- Department of Physics, National University of Singapore, Singapore, Singapore.
- Integrative Sciences and Engineering Programme, National University of Singapore, Singapore, Singapore.
| | - Paolo G Radaelli
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, UK.
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4
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Sedrpooshan M, Bulbucan C, Ternero P, Maltoni P, Preger C, Finizio S, Watts B, Peddis D, Burke AM, Messing ME, Westerström R. Template-free generation and integration of functional 1D magnetic nanostructures. Nanoscale 2023; 15:18500-18510. [PMID: 37942933 PMCID: PMC10667589 DOI: 10.1039/d3nr03878e] [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: 08/03/2023] [Accepted: 10/31/2023] [Indexed: 11/10/2023]
Abstract
The direct integration of 1D magnetic nanostructures into electronic circuits is crucial for realizing their great potential as components in magnetic storage, logical devices, and spintronic applications. Here, we present a novel template-free technique for producing magnetic nanochains and nanowires using directed self-assembly of gas-phase-generated metallic nanoparticles. The 1D nanostructures can be self-assembled along most substrate surfaces and can be freely suspended over micrometer distances, allowing for direct incorporation into different device architectures. The latter is demonstrated by a one-step integration of nanochains onto a pre-patterned Si chip and the fabrication of devices exhibiting magnetoresistance. Moreover, fusing the nanochains into nanowires by post-annealing significantly enhances the magnetic properties, with a 35% increase in the coercivity. Using magnetometry, X-ray microscopy, and micromagnetic simulations, we demonstrate how variations in the orientation of the magnetocrystalline anisotropy and the presence of larger multi-domain particles along the nanochains play a key role in the domain formation and magnetization reversal. Furthermore, it is shown that the increased coercivity in the nanowires can be attributed to the formation of a uniform magnetocrystalline anisotropy along the wires and the onset of exchange interactions.
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Affiliation(s)
- Mehran Sedrpooshan
- NanoLund, Lund University, Box 118, 221 00 Lund, Sweden.
- Synchrotron Radiation Research, Lund University, Box 118, 221 00 Lund, Sweden
| | | | - Pau Ternero
- NanoLund, Lund University, Box 118, 221 00 Lund, Sweden.
- Solid State Physics, Lund University, Box 118, 221 00 Lund, Sweden
| | - Pierfrancesco Maltoni
- Department of Materials Science and Engineering, Uppsala University, Box 35, 751 03 Uppsala, Sweden
| | - Calle Preger
- MAX IV Laboratory, Lund University, Lund, SE-22100, Sweden
- Ergonomics and Aerosol Technology, Lund University, Lund, SE-22100, Sweden
| | | | | | - Davide Peddis
- Institute of Structure of Matter, National Research Council (CNR), Monterotondo Scalo, 00015 Rome, Italy
- Department of Chemistry and Industrial Chemistry, University of Genova, 16146 Genova, Italy
| | - Adam M Burke
- NanoLund, Lund University, Box 118, 221 00 Lund, Sweden.
- Solid State Physics, Lund University, Box 118, 221 00 Lund, Sweden
| | - Maria E Messing
- NanoLund, Lund University, Box 118, 221 00 Lund, Sweden.
- Synchrotron Radiation Research, Lund University, Box 118, 221 00 Lund, Sweden
- Solid State Physics, Lund University, Box 118, 221 00 Lund, Sweden
| | - Rasmus Westerström
- NanoLund, Lund University, Box 118, 221 00 Lund, Sweden.
- Synchrotron Radiation Research, Lund University, Box 118, 221 00 Lund, Sweden
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5
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Finizio S, Bailey JB, Olsthoorn B, Raabe J. Periodogram-Based Detection of Unknown Frequencies in Time-Resolved Scanning Transmission X-ray Microscopy. ACS Nano 2022; 16:21071-21078. [PMID: 36512505 DOI: 10.1021/acsnano.2c08874] [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: 06/17/2023]
Abstract
Pump-probe time-resolved imaging is a powerful technique that enables the investigation of dynamical processes. Signal-to-noise and sampling rate restrictions normally require that cycles of an excitation are repeated many times with the final signal reconstructed using a reference. However, this approach imposes restrictions on the types of dynamical processes that can be measured, namely, that they are phase locked to a known external signal (e.g., a driven oscillation or impulse). This rules out many interesting processes such as auto-oscillations and spontaneously forming populations, e.g., condensates. In this work we present a method for time-resolved imaging, based on the Schuster periodogram, that allows for the reconstruction of dynamical processes where the intrinsic frequency is not known. In our case we use time of arrival detection of X-ray photons to reconstruct magnetic dynamics without using a priori information on the dynamical frequency. This proof-of-principle demonstration will allow for the extension of pump-probe time-resolved imaging to the important class of processes where the dynamics are not locked to a known external signal and in its presented formulation can be readily adopted for X-ray imaging and also adapted for wider use.
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Affiliation(s)
| | - Joe Bilko Bailey
- Paul Scherrer Institut, 5232Villigen PSI, Switzerland
- Institut de Physique, EPFL, 1015Lausanne, Switzerland
| | - Bart Olsthoorn
- Nordita, KTH Royal Institute of Technology and Stockholm University, Hannes Alfvéns väg 12, SE-106 91Stockholm, Sweden
| | - Jörg Raabe
- Paul Scherrer Institut, 5232Villigen PSI, Switzerland
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6
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Juge R, Sisodia N, Larrañaga JU, Zhang Q, Pham VT, Rana KG, Sarpi B, Mille N, Stanescu S, Belkhou R, Mawass MA, Novakovic-Marinkovic N, Kronast F, Weigand M, Gräfe J, Wintz S, Finizio S, Raabe J, Aballe L, Foerster M, Belmeguenai M, Buda-Prejbeanu LD, Pelloux-Prayer J, Shaw JM, Nembach HT, Ranno L, Gaudin G, Boulle O. Skyrmions in synthetic antiferromagnets and their nucleation via electrical current and ultra-fast laser illumination. Nat Commun 2022; 13:4807. [PMID: 35974009 PMCID: PMC9381802 DOI: 10.1038/s41467-022-32525-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [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: 10/25/2021] [Accepted: 08/03/2022] [Indexed: 11/09/2022] Open
Abstract
Magnetic skyrmions are topological spin textures that hold great promise as nanoscale information carriers in non-volatile memory and logic devices. While room-temperature magnetic skyrmions and their current-induced motion were recently demonstrated, the stray field resulting from their finite magnetisation and their topological charge limit their minimum size and reliable motion. Antiferromagnetic skyrmions allow to lift these limitations owing to their vanishing magnetisation and net zero topological charge, promising ultra-small and ultra-fast skyrmions. Here, we report on the observation of isolated skyrmions in compensated synthetic antiferromagnets at zero field and room temperature using X-ray magnetic microscopy. Micromagnetic simulations and an analytical model confirm the chiral antiferromagnetic nature of these skyrmions and allow the identification of the physical mechanisms controlling their size and stability. Finally, we demonstrate the nucleation of synthetic antiferromagnetic skyrmions via local current injection and ultra-fast laser excitation.
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Affiliation(s)
- Roméo Juge
- Univ. Grenoble Alpes, CNRS, CEA, SPINTEC, 38000, Grenoble, France
| | - Naveen Sisodia
- Univ. Grenoble Alpes, CNRS, CEA, SPINTEC, 38000, Grenoble, France
| | | | - Qiang Zhang
- Univ. Grenoble Alpes, CNRS, CEA, SPINTEC, 38000, Grenoble, France
| | - Van Tuong Pham
- Univ. Grenoble Alpes, CNRS, CEA, SPINTEC, 38000, Grenoble, France
| | | | - Brice Sarpi
- Synchrotron SOLEIL, L'Orme des Merisiers, 91190, Saint-Aubin, France
| | - Nicolas Mille
- Synchrotron SOLEIL, L'Orme des Merisiers, 91190, Saint-Aubin, France
| | - Stefan Stanescu
- Synchrotron SOLEIL, L'Orme des Merisiers, 91190, Saint-Aubin, France
| | - Rachid Belkhou
- Synchrotron SOLEIL, L'Orme des Merisiers, 91190, Saint-Aubin, France
| | - Mohamad-Assaad Mawass
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, 12489, Berlin, Germany
| | - Nina Novakovic-Marinkovic
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, 12489, Berlin, Germany
| | - Florian Kronast
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, 12489, Berlin, Germany
| | - Markus Weigand
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109, Berlin, Germany
| | - Joachim Gräfe
- Max Planck Institute for Intelligent Systems, Heisenbergstraße 3, 70569, Stuttgart, Germany
| | - Sebastian Wintz
- Max Planck Institute for Intelligent Systems, Heisenbergstraße 3, 70569, Stuttgart, Germany
| | - Simone Finizio
- Swiss Light Source, Paul Scherrer Institut, 5232, Villigen, Switzerland
| | - Jörg Raabe
- Swiss Light Source, Paul Scherrer Institut, 5232, Villigen, Switzerland
| | - Lucia Aballe
- ALBA Synchrotron Light Facility, 08290, Cerdanyola del Vallès, Barcelona, Spain
| | - Michael Foerster
- ALBA Synchrotron Light Facility, 08290, Cerdanyola del Vallès, Barcelona, Spain
| | - Mohamed Belmeguenai
- Laboratoire des Sciences des Procedés et des Matériaux, CNRS, Univ. Paris 13, 93430, Villetaneuse, France
| | | | | | - Justin M Shaw
- Quantum Electromagnetics Division, National Institute of Standards and Technology, Boulder, CO, 80309, USA
| | - Hans T Nembach
- Quantum Electromagnetics Division, National Institute of Standards and Technology, Boulder, CO, 80309, USA.,Department of Physics, University of Colorado, Boulder, CO, 80309, USA
| | - Laurent Ranno
- Univ. Grenoble Alpes, CNRS, Institut Néel, 38042, Grenoble, France
| | - Gilles Gaudin
- Univ. Grenoble Alpes, CNRS, CEA, SPINTEC, 38000, Grenoble, France
| | - Olivier Boulle
- Univ. Grenoble Alpes, CNRS, CEA, SPINTEC, 38000, Grenoble, France.
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7
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Quessab Y, Xu JW, Cogulu E, Finizio S, Raabe J, Kent AD. Zero-Field Nucleation and Fast Motion of Skyrmions Induced by Nanosecond Current Pulses in a Ferrimagnetic Thin Film. Nano Lett 2022; 22:6091-6097. [PMID: 35877983 DOI: 10.1021/acs.nanolett.2c01038] [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: 06/15/2023]
Abstract
Skyrmion racetrack memories are highly attractive for next-generation data storage technologies. Skyrmions are noncollinear spin textures stabilized by chiral interactions. To achieve a fast-operating memory device, it is critical to move skyrmions at high speeds. The skyrmion dynamics induced by spin-orbit torques (SOTs) in the commonly studied ferromagnetic films is hindered by strong pinning effects and a large skyrmion Hall effect causing deflection of the skyrmion toward the racetrack edge, which can lead to information loss. Here, we investigate the current-induced nucleation and motion of skyrmions in ferrimagnetic Pt/CoGd/(W or Ta) thin films. We first reveal field-free skyrmion nucleation mediated by Joule heating. We then achieve fast skyrmion motion driven by SOTs with velocities as high as 610 m s-1 and a small skyrmion Hall angle |θSkHE| ≲ 3°. Our results show that ferrimagnets are better candidates for fast skyrmion-based memory devices with low risk of information loss.
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Affiliation(s)
- Yassine Quessab
- Center for Quantum Phenomena, Department of Physics, New York University, New York, New York, 10003, United States
| | - Jun-Wen Xu
- Center for Quantum Phenomena, Department of Physics, New York University, New York, New York, 10003, United States
| | - Egecan Cogulu
- Center for Quantum Phenomena, Department of Physics, New York University, New York, New York, 10003, United States
| | - Simone Finizio
- Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Jörg Raabe
- Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Andrew D Kent
- Center for Quantum Phenomena, Department of Physics, New York University, New York, New York, 10003, United States
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8
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Watts B, Finizio S, Raabe J. Quantifying signal quality in scanning transmission X-ray microscopy. J Synchrotron Radiat 2022; 29:1054-1064. [PMID: 35787573 PMCID: PMC9255582 DOI: 10.1107/s1600577522004210] [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] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 04/20/2022] [Indexed: 06/15/2023]
Abstract
While the general effects of experimental conditions such as photon flux and sample thickness on the quality of data acquired by scanning transmission X-ray microscopy (STXM) are widely known at a basic level, the specific details are rarely discussed. This leaves the community open to forming misconceptions that can lead to poor decisions in the design and execution of STXM measurements. A formal treatment of the uncertainty and distortions of transmission signals (due to dark counts, higher-order photons and poor spatial or spectral resolution) is presented here to provide a rational basis for the pursuit of maximizing data quality in STXM experiments. While we find an optimum sample optical density of 2.2 in ideal conditions, the distortions considered tend to have a stronger effect for thicker samples and so ∼1 optical density at the analytical energy is recommended, or perhaps even thinner if significant distortion effects are expected (e.g. lots of higher-order light is present in the instrument). (Note that X-ray absorption calculations based on simple elemental composition do not include near-edge resonances and so cannot accurately represent the spectral resonances typically employed for contrast in STXM.) Further, we present a method for objectively assessing the merits of higher-order suppression in terms of its impact on the quality of transmission measurements that should be useful for the design of synchrotron beamlines.
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Affiliation(s)
- Benjamin Watts
- Swiss Light Source, Paul Scherrer Institute, Forschungsstrasse 111, 5232 Villigen, Switzerland
| | - Simone Finizio
- Swiss Light Source, Paul Scherrer Institute, Forschungsstrasse 111, 5232 Villigen, Switzerland
| | - Jörg Raabe
- Swiss Light Source, Paul Scherrer Institute, Forschungsstrasse 111, 5232 Villigen, Switzerland
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9
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MacKinnon CR, Zeissler K, Finizio S, Raabe J, Marrows CH, Mercer T, Bissell PR, Lepadatu S. Collective skyrmion motion under the influence of an additional interfacial spin-transfer torque. Sci Rep 2022; 12:10786. [PMID: 35750744 PMCID: PMC9232533 DOI: 10.1038/s41598-022-14969-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [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: 02/15/2022] [Accepted: 06/15/2022] [Indexed: 11/26/2022] Open
Abstract
Here we study the effect of an additional interfacial spin-transfer torque, as well as the well-established spin–orbit torque and bulk spin-transfer torque, on skyrmion collections—group of skyrmions dense enough that they are not isolated from one another—in ultrathin heavy metal/ferromagnetic multilayers, by comparing modelling with experimental results. Using a skyrmion collection with a range of skyrmion diameters and landscape disorder, we study the dependence of the skyrmion Hall angle on diameter and velocity, as well as the velocity as a function of diameter. We show that inclusion of the interfacial spin-transfer torque results in reduced skyrmion Hall angles, with values close to experimental results. We also show that for skyrmion collections the velocity is approximately independent of diameter, in marked contrast to the motion of isolated skyrmions, as the group of skyrmions move together at an average group velocity. Moreover, the calculated skyrmion velocities are comparable to those obtained in experiments when the interfacial spin-transfer torque is included. Our results thus show the significance of the interfacial spin-transfer torque in ultrathin magnetic multilayers, which helps to explain the low skyrmion Hall angles and velocities observed in experiment. We conclude that the interfacial spin-transfer torque should be considered in numerical modelling for reproduction of experimental results.
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Affiliation(s)
- Callum R MacKinnon
- Jeremiah Horrocks Institute for Mathematics, Physics and Astronomy, University of Central Lancashire, Preston, PR1 2HE, UK.
| | - Katharina Zeissler
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK.,Bragg Center for Materials Research, University of Leeds, Leeds, LS2 9JT, UK
| | - Simone Finizio
- Swiss Light Source, Paul Scherrer Institut, 5232, Villigen, Switzerland
| | - Jörg Raabe
- Swiss Light Source, Paul Scherrer Institut, 5232, Villigen, Switzerland
| | - Christopher H Marrows
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK.,Bragg Center for Materials Research, University of Leeds, Leeds, LS2 9JT, UK
| | - Tim Mercer
- Jeremiah Horrocks Institute for Mathematics, Physics and Astronomy, University of Central Lancashire, Preston, PR1 2HE, UK
| | - Philip R Bissell
- Jeremiah Horrocks Institute for Mathematics, Physics and Astronomy, University of Central Lancashire, Preston, PR1 2HE, UK
| | - Serban Lepadatu
- Jeremiah Horrocks Institute for Mathematics, Physics and Astronomy, University of Central Lancashire, Preston, PR1 2HE, UK.
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10
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Sala G, Lambert CH, Finizio S, Raposo V, Krizakova V, Krishnaswamy G, Weigand M, Raabe J, Rossell MD, Martinez E, Gambardella P. Asynchronous current-induced switching of rare-earth and transition-metal sublattices in ferrimagnetic alloys. Nat Mater 2022; 21:640-646. [PMID: 35552524 DOI: 10.1038/s41563-022-01248-8] [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: 05/11/2021] [Accepted: 04/04/2022] [Indexed: 06/15/2023]
Abstract
Ferrimagnetic alloys are model systems for understanding the ultrafast magnetization switching in materials with antiferromagnetically coupled sublattices. Here we investigate the dynamics of the rare-earth and transition-metal sublattices in ferrimagnetic GdFeCo and TbCo dots excited by spin-orbit torques with combined temporal, spatial and elemental resolution. We observe distinct switching regimes in which the magnetizations of the two sublattices either remain synchronized throughout the reversal process or switch following different trajectories in time and space. In the latter case, we observe a transient ferromagnetic state that lasts up to 2 ns. The asynchronous switching of the two magnetizations is ascribed to the master-agent dynamics induced by the spin-orbit torques on the transition-metal and rare-earth sublattices and their weak antiferromagnetic coupling, which depends sensitively on the alloy microstructure. Larger antiferromagnetic exchange leads to faster switching and shorter recovery of the magnetization after a current pulse. Our findings provide insight into the dynamics of ferrimagnets and the design of spintronic devices with fast and uniform switching.
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Affiliation(s)
- Giacomo Sala
- Department of Materials, ETH Zurich, Zurich, Switzerland.
| | | | - Simone Finizio
- Swiss Light Source, Paul Scherrer Institut, Villigen, Switzerland
| | - Victor Raposo
- Departamento de Física Aplicada, University of Salamanca, Salamanca, Spain
| | | | | | - Markus Weigand
- Max Planck Institute for Intelligent Systems, Stuttgart, Germany
| | - Jörg Raabe
- Swiss Light Source, Paul Scherrer Institut, Villigen, Switzerland
| | - Marta D Rossell
- Electron Microscopy Center, EMPA, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland
| | - Eduardo Martinez
- Departamento de Física Aplicada, University of Salamanca, Salamanca, Spain
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11
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Finizio S, Donnelly C, Mayr S, Hrabec A, Raabe J. Three-Dimensional Vortex Gyration Dynamics Unraveled by Time-Resolved Soft X-ray Laminography with Freely Selectable Excitation Frequencies. Nano Lett 2022; 22:1971-1977. [PMID: 35148103 DOI: 10.1021/acs.nanolett.1c04662] [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] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The imaging of magneto-dynamical processes has been, so far, mostly a two-dimensional business, also due to the constraints of the available experimental techniques. In this paper, building on the recent developments of soft X-ray magnetic laminography, we present an experimental setup where magneto-dynamical processes can be resolved in all three spatial dimensions and in time at arbitrary frequencies. We employ this setup to investigate two resonant dynamical modes of a CoFeB microstructure, namely, the fundamental vortex gyration mode and a magnetic field-induced domain wall excitation mode. For the former, we observe a large variation of the gyration dynamics across the thickness of the core, coexisting with a breathing mode of the vortex core. For the latter, we observe a uniform displacement of the domain walls across the thickness of the microstructure. The imaging of these two modes establishes the possibility to freely select the excitation frequency for soft X-ray time-resolved laminography, allowing for the investigation of resonant magneto-dynamical processes.
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Affiliation(s)
| | - Claire Donnelly
- Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - Sina Mayr
- Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
| | - Aleš Hrabec
- Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
| | - Jörg Raabe
- Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
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12
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Weßels T, Däster S, Murooka Y, Zingsem B, Migunov V, Kruth M, Finizio S, Lu PH, Kovács A, Oelsner A, Müller-Caspary K, Acremann Y, Dunin-Borkowski RE. Continuous illumination picosecond imaging using a delay line detector in a transmission electron microscope. Ultramicroscopy 2022; 233:113392. [PMID: 35016129 DOI: 10.1016/j.ultramic.2021.113392] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 09/04/2021] [Accepted: 09/09/2021] [Indexed: 11/28/2022]
Abstract
Progress towards analysing transitions between steady states demands improvements in time-resolved imaging, both for fundamental research and for applications in information technology. Transmission electron microscopy is a powerful technique for investigating the atomic structure, chemical composition and electromagnetic properties of materials with high spatial resolution and precision. However, the extraction of information about dynamic processes in the ps time regime is often not possible without extensive modification to the instrument while requiring careful control of the operation conditions to not compromise the beam quality. Here, we avoid these drawbacks by combining a delay line detector with continuous illumination in a transmission electron microscope. We visualize the gyration of a magnetic vortex core in real space and show that magnetization dynamics up to frequencies of 2.3 GHz can be resolved with down to ∼122ps temporal resolution by studying the interaction of an electron beam with a microwave magnetic field. In the future, this approach promises to provide access to resonant dynamics by combining high spatial resolution with sub-ns temporal resolution.
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Affiliation(s)
- Teresa Weßels
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany; Lehrstuhl für Experimentalphysik IV E, RWTH Aachen University, 52056 Aachen, Germany.
| | - Simon Däster
- Laboratory for Solid State Physics, ETH Zurich, 8093 Zurich, Switzerland
| | - Yoshie Murooka
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Benjamin Zingsem
- Faculty of Physics and Center for Nanointegration (CENIDE), University of Duisburg-Essen, 47057 Duisburg, Germany
| | - Vadim Migunov
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany; Central Facility for Electron Microscopy (GFE), RWTH Aachen University, 52074 Aachen, Germany
| | - Maximilian Kruth
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Simone Finizio
- Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Peng-Han Lu
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - András Kovács
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany
| | | | - Knut Müller-Caspary
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany; Department of Chemistry, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, 81377 Munich, Germany
| | - Yves Acremann
- Laboratory for Solid State Physics, ETH Zurich, 8093 Zurich, Switzerland
| | - Rafal E Dunin-Borkowski
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany
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13
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Donnelly C, Hierro-Rodríguez A, Abert C, Witte K, Skoric L, Sanz-Hernández D, Finizio S, Meng F, McVitie S, Raabe J, Suess D, Cowburn R, Fernández-Pacheco A. Complex free-space magnetic field textures induced by three-dimensional magnetic nanostructures. Nat Nanotechnol 2022; 17:136-142. [PMID: 34931031 PMCID: PMC8850196 DOI: 10.1038/s41565-021-01027-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 10/07/2021] [Indexed: 05/23/2023]
Abstract
The design of complex, competing effects in magnetic systems-be it via the introduction of nonlinear interactions1-4, or the patterning of three-dimensional geometries5,6-is an emerging route to achieve new functionalities. In particular, through the design of three-dimensional geometries and curvature, intrastructure properties such as anisotropy and chirality, both geometry-induced and intrinsic, can be directly controlled, leading to a host of new physics and functionalities, such as three-dimensional chiral spin states7, ultrafast chiral domain wall dynamics8-10 and spin textures with new spin topologies7,11. Here, we advance beyond the control of intrastructure properties in three dimensions and tailor the magnetostatic coupling of neighbouring magnetic structures, an interstructure property that allows us to generate complex textures in the magnetic stray field. For this, we harness direct write nanofabrication techniques, creating intertwined nanomagnetic cobalt double helices, where curvature, torsion, chirality and magnetic coupling are jointly exploited. By reconstructing the three-dimensional vectorial magnetic state of the double helices with soft-X-ray magnetic laminography12,13, we identify the presence of a regular array of highly coupled locked domain wall pairs in neighbouring helices. Micromagnetic simulations reveal that the magnetization configuration leads to the formation of an array of complex textures in the magnetic induction, consisting of vortices in the magnetization and antivortices in free space, which together form an effective B field cross-tie wall14. The design and creation of complex three-dimensional magnetic field nanotextures opens new possibilities for smart materials15, unconventional computing2,16, particle trapping17,18 and magnetic imaging19.
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Affiliation(s)
- Claire Donnelly
- Cavendish Laboratory, University of Cambridge, Cambridge, UK.
- Max Planck Institute for Chemical Physics of Solids, Dresden, Germany.
| | - Aurelio Hierro-Rodríguez
- SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow, UK
- Departamento de Física, Universidad de Oviedo, Oviedo, Spain
- CINN (CSIC-Universidad de Oviedo), El Entrego, Spain
| | - Claas Abert
- University of Vienna Research Platform MMM Mathematics-Magnetism-Materials, Vienna, Austria
| | - Katharina Witte
- Swiss Light Source, Paul Scherrer Institute, Villigen, Switzerland
- Berlin Partner für Wirtschaft und Technologie GmbH, Berlin, Germany
| | - Luka Skoric
- Cavendish Laboratory, University of Cambridge, Cambridge, UK
| | | | - Simone Finizio
- Swiss Light Source, Paul Scherrer Institute, Villigen, Switzerland
| | - Fanfan Meng
- Cavendish Laboratory, University of Cambridge, Cambridge, UK
| | - Stephen McVitie
- SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow, UK
| | - Jörg Raabe
- Swiss Light Source, Paul Scherrer Institute, Villigen, Switzerland
| | - Dieter Suess
- University of Vienna Research Platform MMM Mathematics-Magnetism-Materials, Vienna, Austria
| | - Russell Cowburn
- Cavendish Laboratory, University of Cambridge, Cambridge, UK
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14
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Alpert PA, Boucly A, Yang S, Yang H, Kilchhofer K, Luo Z, Padeste C, Finizio S, Ammann M, Watts B. Ice nucleation imaged with X-ray spectro-microscopy. Environ Sci : Atmos 2022; 2:335-351. [PMID: 35694137 PMCID: PMC9119033 DOI: 10.1039/d1ea00077b] [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: 09/27/2021] [Accepted: 02/07/2022] [Indexed: 11/21/2022]
Abstract
Ice nucleation is one of the most uncertain microphysical processes, as it occurs in various ways and on many types of particles. To overcome this challenge, we present a heterogeneous ice nucleation study on deposition ice nucleation and immersion freezing in a novel cryogenic X-ray experiment with the capability to spectroscopically probe individual ice nucleating and non-ice nucleating particles. Mineral dust type particles composed of either ferrihydrite or feldspar were used and mixed with organic matter of either citric acid or xanthan gum. We observed in situ ice nucleation using scanning transmission X-ray microscopy (STXM) and identified unique organic carbon functionalities and iron oxidation state using near-edge X-ray absorption fine structure (NEXAFS) spectroscopy in the new in situ environmental ice cell, termed the ice nucleation X-ray cell (INXCell). Deposition ice nucleation of ferrihydrite occurred at a relative humidity with respect to ice, RHi, between ∼120–138% and temperatures, T ∼ 232 K. However, we also observed water uptake on ferrihydrite at the same T when deposition ice nucleation did not occur. Although, immersion freezing of ferrihydrite both in pure water droplets and in aqueous citric acid occurred at or slightly below conditions for homogeneous freezing, i.e. the effect of ferrihydrite particles acting as a heterogeneous ice nucleus for immersion freezing was small. Microcline K-rich feldspar mixed with xanthan gum was also used in INXCell experiments. Deposition ice nucleation occurred at conditions when xanthan gum was expected to be highly viscous (glassy). At less viscous conditions, immersion freezing was observed. We extended a model for heterogeneous and homogeneous ice nucleation, named the stochastic freezing model (SFM). It was used to quantify heterogeneous ice nucleation rate coefficients, mimic the competition between homogeneous ice nucleation; water uptake; deposition ice nucleation and immersion freezing, and predict the T and RHi at which ice was observed. The importance of ferrihydrite to act as a heterogeneous ice nucleating particle in the atmosphere using the SFM is discussed. Ice nucleation can now be imaged in situ using X-ray spectro-microscopy in a new experiment, which is applied to mineral aerosol particles composed of ferrihydrite or feldspar and associated organic matter.![]()
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Affiliation(s)
- Peter A. Alpert
- Laboratory of Environmental Chemistry, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Anthony Boucly
- Laboratory of Environmental Chemistry, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
- Electrochemistry Laboratory, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Shuo Yang
- Laboratory of Environmental Chemistry, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing Key Laboratory of Indoor Air Quality Evaluation and Control, Tsinghua University, Beijing 100084, China
| | - Huanyu Yang
- Laboratory of Environmental Chemistry, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Kevin Kilchhofer
- Laboratory of Environmental Chemistry, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Zhaochu Luo
- Laboratory for Multiscale Materials Experiments, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zürich, Zürich, Switzerland
| | - Celestino Padeste
- Laboratory of Nanoscale Biology, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Simone Finizio
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Markus Ammann
- Laboratory of Environmental Chemistry, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Benjamin Watts
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
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15
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Finizio S, Watts B, Raabe J. Why is my image noisy? A look into the terms contributing to a time-resolved X-ray microscopy image. J Synchrotron Radiat 2021; 28:1146-1158. [PMID: 34212878 DOI: 10.1107/s1600577521004240] [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] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 04/20/2021] [Indexed: 06/13/2023]
Abstract
Through Monte Carlo simulations, we investigate how various experimental parameters can influence the quality of time-resolved scanning transmission X-ray microscopy images. In particular, the effect of the X-ray photon flux, of the thickness of the investigated samples, and of the frequency of the dynamical process under investigation on the resulting time-resolved image are investigated. The ideal sample and imaging conditions that allow for an optimal image quality are then identifed.
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Affiliation(s)
- Simone Finizio
- Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Benjamin Watts
- Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Jörg Raabe
- Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
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16
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Mayr S, Flajšman L, Finizio S, Hrabec A, Weigand M, Förster J, Stoll H, Heyderman LJ, Urbánek M, Wintz S, Raabe J. Spin-Wave Emission from Vortex Cores under Static Magnetic Bias Fields. Nano Lett 2021; 21:1584-1590. [PMID: 33544597 DOI: 10.1021/acs.nanolett.0c03740] [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] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We studied the influence of a static in-plane magnetic field on the alternating-field-driven emission of nanoscale spin waves from magnetic vortex cores. Time-resolved scanning transmission X-ray microscopy was used to image spin waves in disk structures of synthetic ferrimagnets and single ferromagnetic layers. For both systems, it was found that an increasing magnetic bias field continuously displaces the wave-emitting vortex core from the center of the disk toward its edge without noticeably altering the spin-wave dispersion relation. In the case of the single-layer disk, an anisotropic lateral expansion of the core occurs at higher magnetic fields, which leads to a directional rather than radial-isotropic emission and propagation of waves. Micromagnetic simulations confirm these findings and further show that focusing effects occur in such systems, depending on the shape of the core and controlled by the static magnetic bias field.
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Affiliation(s)
- Sina Mayr
- Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
| | - Lukáš Flajšman
- CEITEC BUT, Brno University of Technology, 61200 Brno, Czech Republic
- NanoSpin, Department of Applied Physics, Aalto University, P.O. Box 15100, FI-00076 Aalto, Finland
| | | | - Aleš Hrabec
- Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
- Laboratory for Magnetism and Interface Physics, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
| | | | - Johannes Förster
- Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - Hermann Stoll
- Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
- Institute of Physics, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
| | - Laura J Heyderman
- Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
| | - Michal Urbánek
- CEITEC BUT, Brno University of Technology, 61200 Brno, Czech Republic
| | - Sebastian Wintz
- Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
- Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - Jörg Raabe
- Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
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17
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Finizio S, Mayr S, Raabe J. Time-of-arrival detection for time-resolved scanning transmission X-ray microscopy imaging. J Synchrotron Radiat 2020; 27:1320-1325. [PMID: 32876607 PMCID: PMC7467344 DOI: 10.1107/s1600577520007262] [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: 04/08/2020] [Accepted: 06/01/2020] [Indexed: 06/11/2023]
Abstract
A setup for time-resolved scanning transmission X-ray microscopy imaging is presented, which allows for an increase in the temporal resolution without the requirement of operating the synchrotron light source with low-α optics through the measurement of the time-of-arrival of the X-ray photons. Measurements of two filling patterns in hybrid mode of the Swiss Light Source are presented as a first proof-of-principle and benchmark for the performances of this new setup. From these measurements, a temporal resolution on the order of 20-30 ps could be determined.
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Affiliation(s)
- Simone Finizio
- Paul Scherrer Institut, Forschungsstrasse 111, 5232 Villigen PSI, Switzerland
| | - Sina Mayr
- Paul Scherrer Institut, Forschungsstrasse 111, 5232 Villigen PSI, Switzerland
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
| | - Jörg Raabe
- Paul Scherrer Institut, Forschungsstrasse 111, 5232 Villigen PSI, Switzerland
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18
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Donnelly C, Finizio S, Gliga S, Holler M, Hrabec A, Odstrčil M, Mayr S, Scagnoli V, Heyderman LJ, Guizar-Sicairos M, Raabe J. Time-resolved imaging of three-dimensional nanoscale magnetization dynamics. Nat Nanotechnol 2020; 15:356-360. [PMID: 32094498 DOI: 10.1038/s41565-020-0649-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 01/27/2020] [Indexed: 05/25/2023]
Abstract
Understanding and control of the dynamic response of magnetic materials with a three-dimensional magnetization distribution is important both fundamentally and for technological applications. From a fundamental point of view, the internal magnetic structure and dynamics in bulk materials still need to be mapped1, including the dynamic properties of topological structures such as vortices2, magnetic singularities3 or skyrmion lattices4. From a technological point of view, the response of inductive materials to magnetic fields and spin-polarized currents is essential for magnetic sensors and data storage devices5. Here, we demonstrate time-resolved magnetic laminography, a pump-probe technique, which offers access to the temporal evolution of a three-dimensional magnetic microdisc with nanoscale resolution, and with a synchrotron-limited temporal resolution of 70 ps. We image the dynamic response to a 500 MHz magnetic field of the complex three-dimensional magnetization in a two-phase bulk magnet with a lateral spatial resolution of 50 nm. This is achieved with a stroboscopic measurement consisting of eight time steps evenly spaced over 2 ns. These measurements map the spatial transition between domain wall motion and the dynamics of a uniform magnetic domain that is attributed to variations in the magnetization state across the phase boundary. Our technique, which probes three-dimensional magnetic structures with temporal resolution, enables the experimental investigation of functionalities arising from dynamic phenomena in bulk and three-dimensional patterned nanomagnets6.
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Affiliation(s)
- Claire Donnelly
- Cavendish Laboratory, University of Cambridge, Cambridge, UK.
- Paul Scherrer Institute, Villigen, Switzerland.
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, Zurich, Switzerland.
| | | | - Sebastian Gliga
- Paul Scherrer Institute, Villigen, Switzerland
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, Zurich, Switzerland
- SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow, UK
| | | | - Aleš Hrabec
- Paul Scherrer Institute, Villigen, Switzerland
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, Zurich, Switzerland
- Laboratory for Magnetism and Interface Physics, Department of Materials, ETH Zurich, Zurich, Switzerland
| | | | - Sina Mayr
- Paul Scherrer Institute, Villigen, Switzerland
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, Zurich, Switzerland
| | - Valerio Scagnoli
- Paul Scherrer Institute, Villigen, Switzerland
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, Zurich, Switzerland
| | - Laura J Heyderman
- Paul Scherrer Institute, Villigen, Switzerland
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, Zurich, Switzerland
| | | | - Jörg Raabe
- Paul Scherrer Institute, Villigen, Switzerland.
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19
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Albisetti E, Tacchi S, Silvani R, Scaramuzzi G, Finizio S, Wintz S, Rinaldi C, Cantoni M, Raabe J, Carlotti G, Bertacco R, Riedo E, Petti D. Optically Inspired Nanomagnonics with Nonreciprocal Spin Waves in Synthetic Antiferromagnets. Adv Mater 2020; 32:e1906439. [PMID: 31944413 DOI: 10.1002/adma.201906439] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 11/21/2019] [Indexed: 06/10/2023]
Abstract
Integrated optically inspired wave-based processing is envisioned to outperform digital architectures in specific tasks, such as image processing and speech recognition. In this view, spin waves represent a promising route due to their nanoscale wavelength in the gigahertz frequency range and rich phenomenology. Here, a versatile, optically inspired platform using spin waves is realized, demonstrating the wavefront engineering, focusing, and robust interference of spin waves with nanoscale wavelength. In particular, magnonic nanoantennas based on tailored spin textures are used for launching spatially shaped coherent wavefronts, diffraction-limited spin-wave beams, and generating robust multi-beam interference patterns, which spatially extend for several times the spin-wave wavelength. Furthermore, it is shown that intriguing features, such as resilience to back reflection, naturally arise from the spin-wave nonreciprocity in synthetic antiferromagnets, preserving the high quality of the interference patterns from spurious counterpropagating modes. This work represents a fundamental step toward the realization of nanoscale optically inspired devices based on spin waves.
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Affiliation(s)
- Edoardo Albisetti
- Dipartimento di Fisica, Politecnico di Milano, Via Giuseppe Colombo, 81, Milano, 20133, Italy
- Advanced Science Research Center, CUNY Graduate Center, 85, St. Nicholas Terrace, New York, NY, 10031, USA
| | - Silvia Tacchi
- Istituto Officina dei Materiali del CNR (CNR-IOM), Sede Secondaria di Perugia, c/o Dipartimento di Fisica e Geologia, Università di Perugia, Perugia, I-06123, Italy
| | - Raffaele Silvani
- Istituto Officina dei Materiali del CNR (CNR-IOM), Sede Secondaria di Perugia, c/o Dipartimento di Fisica e Geologia, Università di Perugia, Perugia, I-06123, Italy
- Dipartimento di Fisica e Geologia, Università di Perugia, Via A. Pascoli, Perugia, I-06123, Italy
| | - Giuseppe Scaramuzzi
- Dipartimento di Fisica, Politecnico di Milano, Via Giuseppe Colombo, 81, Milano, 20133, Italy
| | - Simone Finizio
- Swiss Light Source, Paul Scherrer Institut, Villigen, PSI CH-5232, Switzerland
| | - Sebastian Wintz
- Swiss Light Source, Paul Scherrer Institut, Villigen, PSI CH-5232, Switzerland
| | - Christian Rinaldi
- Dipartimento di Fisica, Politecnico di Milano, Via Giuseppe Colombo, 81, Milano, 20133, Italy
| | - Matteo Cantoni
- Dipartimento di Fisica, Politecnico di Milano, Via Giuseppe Colombo, 81, Milano, 20133, Italy
| | - Jörg Raabe
- Swiss Light Source, Paul Scherrer Institut, Villigen, PSI CH-5232, Switzerland
| | - Giovanni Carlotti
- Istituto Officina dei Materiali del CNR (CNR-IOM), Sede Secondaria di Perugia, c/o Dipartimento di Fisica e Geologia, Università di Perugia, Perugia, I-06123, Italy
| | - Riccardo Bertacco
- Dipartimento di Fisica, Politecnico di Milano, Via Giuseppe Colombo, 81, Milano, 20133, Italy
| | - Elisa Riedo
- Advanced Science Research Center, CUNY Graduate Center, 85, St. Nicholas Terrace, New York, NY, 10031, USA
- Tandon School of Engineering, New York University, New York, NY, 11201, USA
| | - Daniela Petti
- Dipartimento di Fisica, Politecnico di Milano, Via Giuseppe Colombo, 81, Milano, 20133, Italy
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20
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Malik IA, Huang H, Wang Y, Wang X, Xiao C, Sun Y, Ullah R, Zhang Y, Wang J, Malik MA, Ahmed I, Xiong C, Finizio S, Kläui M, Gao P, Wang J, Zhang J. Inhomogeneous-strain-induced magnetic vortex cluster in one-dimensional manganite wire. Sci Bull (Beijing) 2020; 65:201-207. [PMID: 36659173 DOI: 10.1016/j.scib.2019.11.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2019] [Revised: 10/23/2019] [Accepted: 11/12/2019] [Indexed: 01/21/2023]
Abstract
Mixed-valance manganites with strong electron correlation exhibit strong potential for spintronics, where emergent magnetic behaviors, such as propagation of high-frequency spin waves and giant topological Hall Effects can be driven by their mesoscale spin textures. Here, we create magnetic vortex clusters with flux closure spin configurations in single-crystal La0.67Sr0.33MnO3 wire. A distinctive transformation from out-of-plane domains to a vortex state is directly visualized using magnetic force microscopy at 4 K in wires when the width is below 1.0 μm. The phase-field modeling indicates that the inhomogeneous strain, accompanying with shape anisotropy, plays a key role for stabilizing the flux-closure spin structure. This work offers a new perspective for understanding and manipulating the non-trivial spin textures in strongly correlated systems.
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Affiliation(s)
| | - Houbing Huang
- Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, China
| | - Yu Wang
- Department of Engineering Mechanics & Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, Zhejiang University, Hangzhou 310027, China
| | - Xueyun Wang
- School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Cui Xiao
- Department of Physics, University of Science and Technology Beijing, Beijing 100083, China
| | - Yuanwei Sun
- International Center for Quantum Materials and Electron Microscopy Laboratory, School of Physics, Peking University, Beijing 100871, China
| | - Rizwan Ullah
- Department of Physics, Beijing Normal University, Beijing 100875, China
| | - Yuelin Zhang
- Department of Physics, Beijing Normal University, Beijing 100875, China
| | - Jing Wang
- Department of Physics, Beijing Normal University, Beijing 100875, China
| | | | - Irfan Ahmed
- Department of Physics, Beijing Normal University, Beijing 100875, China
| | - Changmin Xiong
- Department of Physics, Beijing Normal University, Beijing 100875, China.
| | - Simone Finizio
- Department of Physics, Johannes Gutenberg-University Mainz, Mainz 55099, Germany; Graduate School of Excellence Materials Science in Mainz, Mainz 55128, Germany
| | - Mathias Kläui
- Department of Physics, Johannes Gutenberg-University Mainz, Mainz 55099, Germany; Graduate School of Excellence Materials Science in Mainz, Mainz 55128, Germany
| | - Peng Gao
- International Center for Quantum Materials and Electron Microscopy Laboratory, School of Physics, Peking University, Beijing 100871, China; Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
| | - Jie Wang
- Department of Engineering Mechanics & Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, Zhejiang University, Hangzhou 310027, China.
| | - Jinxing Zhang
- Department of Physics, Beijing Normal University, Beijing 100875, China.
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21
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Witte K, Späth A, Finizio S, Donnelly C, Watts B, Sarafimov B, Odstrcil M, Guizar-Sicairos M, Holler M, Fink RH, Raabe J. From 2D STXM to 3D Imaging: Soft X-ray Laminography of Thin Specimens. Nano Lett 2020; 20:1305-1314. [PMID: 31951418 DOI: 10.1021/acs.nanolett.9b04782] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
X-ray tomography has become an indispensable tool for studying complex 3D interior structures with high spatial resolution. Three-dimensional imaging using soft X-rays offers powerful contrast mechanisms but has seen limited success with tomography due to the restrictions imposed by the much lower energy of the probe beam. The generalized geometry of laminography, characterized by a tilted axis of rotation, provides nm-scale 3D resolution for the investigation of extended (mm range) but thin (μm to nm) samples that are well suited to soft X-ray studies. This work reports on the implementation of soft X-ray laminography (SoXL) at the scanning transmission X-ray spectromicroscope of the PolLux beamline at the Swiss Light Source, Paul Scherrer Institut, which enables 3D imaging of extended specimens from 270 to 1500 eV. Soft X-ray imaging provides contrast mechanisms for both chemical sensitivity to molecular bonds and oxidation states and magnetic dichroism due to the much stronger attenuation of X-rays in this energy range. The presented examples of applications range from functionalized nanomaterials to biological photonic crystals and sophisticated nanoscaled magnetic domain patterns, thus illustrating the wide fields of research that can benefit from SoXL.
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Affiliation(s)
- Katharina Witte
- Swiss Light Source , Paul Scherrer Institut , Forschungsstrasse 111 , 5232 Villigen , Switzerland
| | - Andreas Späth
- Department Chemie und Pharmazie, Physikalische Chemie , Friedrich-Alexander-Universität Erlangen-Nürnberg , Egerlandstrasse 3 , 91058 Erlangen , Germany
| | - Simone Finizio
- Swiss Light Source , Paul Scherrer Institut , Forschungsstrasse 111 , 5232 Villigen , Switzerland
| | - Claire Donnelly
- Cavendish Laboratory , University of Cambridge , JJ Thomson Avenue , Cambridge , CB3 0HE , United Kingdom
| | - Benjamin Watts
- Swiss Light Source , Paul Scherrer Institut , Forschungsstrasse 111 , 5232 Villigen , Switzerland
| | - Blagoj Sarafimov
- Swiss Light Source , Paul Scherrer Institut , Forschungsstrasse 111 , 5232 Villigen , Switzerland
| | - Michal Odstrcil
- Swiss Light Source , Paul Scherrer Institut , Forschungsstrasse 111 , 5232 Villigen , Switzerland
| | - Manuel Guizar-Sicairos
- Swiss Light Source , Paul Scherrer Institut , Forschungsstrasse 111 , 5232 Villigen , Switzerland
| | - Mirko Holler
- Swiss Light Source , Paul Scherrer Institut , Forschungsstrasse 111 , 5232 Villigen , Switzerland
| | - Rainer H Fink
- Department Chemie und Pharmazie, Physikalische Chemie , Friedrich-Alexander-Universität Erlangen-Nürnberg , Egerlandstrasse 3 , 91058 Erlangen , Germany
| | - Jörg Raabe
- Swiss Light Source , Paul Scherrer Institut , Forschungsstrasse 111 , 5232 Villigen , Switzerland
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22
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Finizio S, Zeissler K, Wintz S, Mayr S, Weßels T, Huxtable AJ, Burnell G, Marrows CH, Raabe J. Deterministic Field-Free Skyrmion Nucleation at a Nanoengineered Injector Device. Nano Lett 2019; 19:7246-7255. [PMID: 31525983 DOI: 10.1021/acs.nanolett.9b02840] [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] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Magnetic skyrmions are topological solitons promising for applications as encoders for digital information. A number of different skyrmion-based memory devices have been recently proposed. In order to demonstrate a viable skyrmion-based memory device, it is necessary to reliably and reproducibly nucleate, displace, detect, and delete the magnetic skyrmions, possibly in the absence of external applied magnetic fields, which would needlessly complicate the device design. While the skyrmion displacement and detection have both been thoroughly investigated, much less attention has been dedicated to the study of the skyrmion nucleation process and its sub-nanosecond dynamics. In this study, we investigate the nucleation of magnetic skyrmions from a dedicated nanoengineered injector, demonstrating the reliable magnetic skyrmion nucleation at the remnant state. The sub-nanosecond dynamics of the skyrmion nucleation process were also investigated, allowing us to shine light on the physical processes driving the nucleation.
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Affiliation(s)
- Simone Finizio
- Paul Scherrer Institut , 5232 Villigen PSI , Switzerland
| | - Katharina Zeissler
- School of Physics and Astronomy , University of Leeds , Leeds LS2 9JT , United Kingdom
| | - Sebastian Wintz
- Paul Scherrer Institut , 5232 Villigen PSI , Switzerland
- Institute of Ion Beam Physics and Materials Research , Helmholtz-Zentrum Dresden-Rossendorf , 01328 Dresden , Germany
| | - Sina Mayr
- Paul Scherrer Institut , 5232 Villigen PSI , Switzerland
- Laboratory for Mesoscopic Systems, Department of Materials , ETH Zürich , 8093 Zürich , Switzerland
| | - Teresa Weßels
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute , Forschungszentrum Jülich GmbH , 52425 Jülich , Germany
| | - Alexandra J Huxtable
- School of Physics and Astronomy , University of Leeds , Leeds LS2 9JT , United Kingdom
| | - Gavin Burnell
- School of Physics and Astronomy , University of Leeds , Leeds LS2 9JT , United Kingdom
| | - Christopher H Marrows
- School of Physics and Astronomy , University of Leeds , Leeds LS2 9JT , United Kingdom
| | - Jörg Raabe
- Paul Scherrer Institut , 5232 Villigen PSI , Switzerland
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23
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Roy K, Raabe J, Schifferle P, Finizio S, Kleibert A, van Bokhoven JA, Artiglia L. Design and performance of a new setup for spatially resolved transmission X-ray photoelectron spectroscopy at the Swiss Light Source. J Synchrotron Radiat 2019; 26:785-792. [PMID: 31074443 PMCID: PMC6510197 DOI: 10.1107/s1600577519002984] [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] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 02/26/2019] [Indexed: 06/09/2023]
Abstract
The successful design, installation and operation of a high spatial resolution X-ray photoelectron spectrometer at the Swiss Light Source is presented. In this instrument, a Fresnel zone plate is used to focus an X-ray beam onto the sample and an electron analyzer positioned at 45° with respect to the incoming beam direction is used to collect photoelectrons from the backside of the sample. By raster scanning the sample, transmitted current, X-ray absorption and X-ray photoemission maps can be simultaneously acquired. This work demonstrates that chemical information can be extracted with micrometre resolution; the results suggest that a spatial resolution better than 100 nm can be achieved with this approach in future. This kind of photoelectron spectromicroscope will allow in situ measurements with high spatial resolution also under ambient pressure conditions (in the millibar range). Element-specific X-ray photoemission maps can be obtained before and while exposing the sample to gas/gas mixtures to show morphological and chemical changes of the surface.
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Affiliation(s)
- Kanak Roy
- Institute for Chemical and Bioengineering, ETH Zürich, Zürich 8093, Switzerland
| | - Joerg Raabe
- Swiss Light Source, Paul Scherrer Institute, Villigen 5232, Switzerland
| | - Pascal Schifferle
- Swiss Light Source, Paul Scherrer Institute, Villigen 5232, Switzerland
| | - Simone Finizio
- Swiss Light Source, Paul Scherrer Institute, Villigen 5232, Switzerland
| | - Armin Kleibert
- Swiss Light Source, Paul Scherrer Institute, Villigen 5232, Switzerland
| | - Jeroen A. van Bokhoven
- Institute for Chemical and Bioengineering, ETH Zürich, Zürich 8093, Switzerland
- Laboratory for Catalysis and Sustainable Chemistry, Paul Scherrer Institute, Villigen 5232, Switzerland
| | - Luca Artiglia
- Laboratory for Catalysis and Sustainable Chemistry, Paul Scherrer Institute, Villigen 5232, Switzerland
- Laboratory of Environmental Chemistry, Paul Scherrer Institute, Villigen 5232, Switzerland
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24
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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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25
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Foerster M, Fina I, Finizio S, Casals B, Mandziak A, Fauth F, Aballe L. Disclosing odd symmetry, strain driven magnetic response of Co on Pt/PMN-PT (0 1 1). J Phys Condens Matter 2019; 31:084003. [PMID: 30537690 DOI: 10.1088/1361-648x/aaf7ee] [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] [Indexed: 06/09/2023]
Abstract
An odd-symmetry magnetic response of multiferroic composites comprising ultrathin Co layers on Pt electrodes on [Pb(Mg0.33Nb0.67)O3](1-x)[PbTiO3] x (PMN-PT) (0 1 1) piezoelectric substrates is observed upon electrical poling of the PMN-PT substrates: the magnetic easy axis of the Co rotates by 90° in-plane between oppositely poled ferroelectric states, mimicking the signature of a surface polarization charge driven effect, which however can be excluded from the presence of the thick Pt interlayer. The origin for this unexpected behavior is as an odd symmetry piezoelectric response of the PMN-PT substrate, as indicated by x-ray diffraction with applied poling, in combination with conventional magnetoelastic coupling. Ferroelectric characterization reveals corresponding features, possibly related to an unswitchable polarization component.
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Affiliation(s)
- Michael Foerster
- Alba Synchrotron Light Facility, Carrer de la llum 2-26, 08290 Cerdanyola del Valles, Barcelona, Spain
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26
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Finizio S, Wintz S, Zeissler K, Sadovnikov AV, Mayr S, Nikitov SA, Marrows CH, Raabe J. Dynamic Imaging of the Delay- and Tilt-Free Motion of Néel Domain Walls in Perpendicularly Magnetized Superlattices. Nano Lett 2019; 19:375-380. [PMID: 30517003 DOI: 10.1021/acs.nanolett.8b04091] [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] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We report on the time-resolved investigation of current- and field-induced domain wall motion in the flow regime in perpendicularly magnetized microwires exhibiting antisymmetric exchange interaction by means of scanning transmission X-ray microscopy with a 200 ps time step. The sub-ns time step of the dynamical images allowed us to observe the absence of incubation times for the motion of the domain wall within an uncertainty of 200 ps, together with indications for a negligible inertia of the domain wall. Furthermore, we observed that, for short current and magnetic field pulses, the magnetic domain walls do not exhibit a tilting during their motion, providing a mechanism for the fast, tilt-free, current-induced motion of magnetic domain walls.
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Affiliation(s)
- Simone Finizio
- Swiss Light Source , Paul Scherrer Institut , 5232 Villigen PSI , Switzerland
| | - Sebastian Wintz
- Swiss Light Source , Paul Scherrer Institut , 5232 Villigen PSI , Switzerland
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf , 01328 Dresden , Germany
| | - Katharina Zeissler
- School of Physics and Astronomy , University of Leeds , Leeds LS2 9JT , United Kingdom
| | - Alexandr V Sadovnikov
- Laboratory Metamaterials , Saratov State University , Saratov 410012 , Russia
- Kotel'nikov Institute of Radioengineering and Electronics , Russian Academy of Sciences , Moscow 125009 , Russia
| | - Sina Mayr
- Swiss Light Source , Paul Scherrer Institut , 5232 Villigen PSI , Switzerland
- Department of Materials, Laboratory for Mesoscopic Systems , ETH Zürich , 8093 Zürich , Switzerland
| | - Sergey A Nikitov
- Laboratory Metamaterials , Saratov State University , Saratov 410012 , Russia
- Kotel'nikov Institute of Radioengineering and Electronics , Russian Academy of Sciences , Moscow 125009 , Russia
| | - Christopher H Marrows
- School of Physics and Astronomy , University of Leeds , Leeds LS2 9JT , United Kingdom
| | - Jörg Raabe
- Swiss Light Source , Paul Scherrer Institut , 5232 Villigen PSI , Switzerland
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27
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Foerster M, Statuto N, Casals B, Hernández-Mínguez A, Finizio S, Mandziak A, Aballe L, Hernàndez Ferràs JM, Macià F. Quantification of propagating and standing surface acoustic waves by stroboscopic X-ray photoemission electron microscopy. J Synchrotron Radiat 2019; 26:184-193. [PMID: 30655484 DOI: 10.1107/s1600577518015370] [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: 07/26/2018] [Accepted: 10/30/2018] [Indexed: 06/09/2023]
Abstract
The quantification of surface acoustic waves (SAWs) in LiNbO3 piezoelectric crystals by stroboscopic X-ray photoemission electron microscopy (XPEEM), with a temporal smearing below 80 ps and a spatial resolution below 100 nm, is reported. The contrast mechanism is the varying piezoelectric surface potential associated with the SAW phase. Thus, kinetic energy spectra of photoemitted secondary electrons measure directly the SAW electrical amplitude and allow for the quantification of the associated strain. The stroboscopic imaging combined with a deliberate detuning allows resolving and quantifying the respective standing and propagating components of SAWs from a superposition of waves. Furthermore, standing-wave components can also be imaged by low-energy electron microscopy (LEEM). Our method opens the door to studies that quantitatively correlate SAWs excitation with a variety of sample electronic, magnetic and chemical properties.
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Affiliation(s)
- Michael Foerster
- Experiments Divison, ALBA Synchrotron, Carrer de la Llum 2-26, Cerdanyola del Valles, 08290 Barcelona, Spain
| | - Nahuel Statuto
- Department of Condensed Matter Physics, University of Barcelona, 08028 Barcelona, Spain
| | - Blai Casals
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, 08193 Bellaterra, Spain
| | - Alberto Hernández-Mínguez
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin eV, Germany
| | - Simone Finizio
- Institut für Physik, Johannes Gutenberg Universität, Staudingerweg 7, D-55128 Mainz, Germany
| | - Ania Mandziak
- Experiments Divison, ALBA Synchrotron, Carrer de la Llum 2-26, Cerdanyola del Valles, 08290 Barcelona, Spain
| | - Lucia Aballe
- Experiments Divison, ALBA Synchrotron, Carrer de la Llum 2-26, Cerdanyola del Valles, 08290 Barcelona, Spain
| | | | - Ferran Macià
- Department of Condensed Matter Physics, University of Barcelona, 08028 Barcelona, Spain
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28
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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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29
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Zeissler K, Finizio S, Shahbazi K, Massey J, Ma'Mari FA, Bracher DM, Kleibert A, Rosamond MC, Linfield EH, Moore TA, Raabe J, Burnell G, Marrows CH. Discrete Hall resistivity contribution from Néel skyrmions in multilayer nanodiscs. Nat Nanotechnol 2018; 13:1161-1166. [PMID: 30275493 DOI: 10.1038/s41565-018-0268-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 08/28/2018] [Indexed: 06/08/2023]
Abstract
Magnetic skyrmions are knot-like quasiparticles. They are candidates for non-volatile data storage in which information is moved between fixed read and write terminals. The read-out operation of skyrmion-based spintronic devices will rely on the electrical detection of a single magnetic skyrmion within a nanostructure. Here we present Pt/Co/Ir nanodiscs that support skyrmions at room temperature. We measured the Hall resistivity and simultaneously imaged the spin texture using magnetic scanning transmission X-ray microscopy. The Hall resistivity is correlated to both the presence and size of the skyrmion. The size-dependent part matches the expected anomalous Hall signal when averaging the magnetization over the entire disc. We observed a resistivity contribution that only depends on the number and sign of skyrmion-like objects present in the disc. Each skyrmion gives rise to 22 ± 2 nΩ cm irrespective of its size. This contribution needs to be considered in all-electrical detection schemes applied to skyrmion-based devices. Not only the area of Néel skyrmions but also their number and sign contribute to their Hall resistivity.
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Affiliation(s)
| | - Simone Finizio
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI, Switzerland
| | - Kowsar Shahbazi
- School of Physics and Astronomy, University of Leeds, Leeds, UK
| | - Jamie Massey
- School of Physics and Astronomy, University of Leeds, Leeds, UK
| | - Fatma Al Ma'Mari
- School of Physics and Astronomy, University of Leeds, Leeds, UK
- Department of Physics, Sultan Qaboos University, Muscat, Oman
| | - David M Bracher
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI, Switzerland
| | - Armin Kleibert
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI, Switzerland
| | - Mark C Rosamond
- School of Electronic and Electrical Engineering, University of Leeds, Leeds, UK
| | - Edmund H Linfield
- School of Electronic and Electrical Engineering, University of Leeds, Leeds, UK
| | - Thomas A Moore
- School of Physics and Astronomy, University of Leeds, Leeds, UK
| | - Jörg Raabe
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI, Switzerland
| | - Gavin Burnell
- School of Physics and Astronomy, University of Leeds, Leeds, UK
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30
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Finizio S, Wintz S, Gliga S, Kirk E, Suszka AK, Wohlhüter P, Zeissler K, Raabe J. Unexpected field-induced dynamics in magnetostrictive microstructured elements under isotropic strain. J Phys Condens Matter 2018; 30:314001. [PMID: 29923838 DOI: 10.1088/1361-648x/aacddd] [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] [Indexed: 06/08/2023]
Abstract
We investigated the influence of an isotropic strain on the magnetization dynamics of microstructured magnetostrictive Co40Fe40B20 (CoFeB) elements with time-resolved scanning transmission x-ray microscopy. We observed that the application of isotropic strain leads to changes in the behavior of the microstructured magnetostrictive elements that cannot be fully explained by the volume magnetostriction term. Therefore, our results prompt for an alternative explanation to the current models used for the interpretation of the influence of mechanical strain on the dynamical processes of magnetostrictive materials.
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31
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Zimmermann M, Meier TNG, Dirnberger F, Kákay A, Decker M, Wintz S, Finizio S, Josten E, Raabe J, Kronseder M, Bougeard D, Lindner J, Back CH. Origin and Manipulation of Stable Vortex Ground States in Permalloy Nanotubes. Nano Lett 2018; 18:2828-2834. [PMID: 29620910 DOI: 10.1021/acs.nanolett.7b05222] [Citation(s) in RCA: 3] [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: 06/08/2023]
Abstract
We present a detailed study on the static magnetic properties of individual permalloy nanotubes (NTs) with hexagonal cross-sections. Anisotropic magnetoresistance (AMR) measurements and scanning transmission X-ray microscopy (STXM) are used to investigate their magnetic ground states and its stability. We find that the magnetization in zero applied magnetic field is in a very stable vortex state. Its origin is attributed to a strong growth-induced anisotropy with easy axis perpendicular to the long axis of the tubes. AMR measurements of individual NTs in combination with micromagnetic simulations allow the determination of the magnitude of the growth-induced anisotropy for different types of NT coatings. We show that the strength of the anisotropy can be controlled by introducing a buffer layer underneath the magnetic layer. The magnetic ground states depend on the external magnetic field history and are directly imaged using STXM. Stable vortex domains can be introduced by external magnetic fields and can be erased by radio-frequency magnetic fields applied at the center of the tubes via a strip line antenna.
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Affiliation(s)
- Michael Zimmermann
- Physics Department , Universität Regensburg , Universitätsstraße 31 , D-93053 Regensburg , Germany
| | | | - Florian Dirnberger
- Physics Department , Universität Regensburg , Universitätsstraße 31 , D-93053 Regensburg , Germany
| | - Attila Kákay
- Helmholtz-Zentrum, Dresden Rossendorf , Institute of Ion Beam Physics and Material Research , Bautzner Landstraße 400 , 01328 Dresden , Germany
| | - Martin Decker
- Physics Department , Universität Regensburg , Universitätsstraße 31 , D-93053 Regensburg , Germany
| | - Sebastian Wintz
- Helmholtz-Zentrum, Dresden Rossendorf , Institute of Ion Beam Physics and Material Research , Bautzner Landstraße 400 , 01328 Dresden , Germany
- Paul Scherrer Institut , 5232 Villigen , Switzerland
| | | | - Elisabeth Josten
- Helmholtz-Zentrum, Dresden Rossendorf , Institute of Ion Beam Physics and Material Research , Bautzner Landstraße 400 , 01328 Dresden , Germany
| | - Jörg Raabe
- Paul Scherrer Institut , 5232 Villigen , Switzerland
| | - Matthias Kronseder
- Physics Department , Universität Regensburg , Universitätsstraße 31 , D-93053 Regensburg , Germany
| | - Dominique Bougeard
- Physics Department , Universität Regensburg , Universitätsstraße 31 , D-93053 Regensburg , Germany
| | - Jürgen Lindner
- Helmholtz-Zentrum, Dresden Rossendorf , Institute of Ion Beam Physics and Material Research , Bautzner Landstraße 400 , 01328 Dresden , Germany
| | - Christian Horst Back
- Physics Department , Universität Regensburg , Universitätsstraße 31 , D-93053 Regensburg , Germany
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32
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Woo S, Song KM, Zhang X, Zhou Y, Ezawa M, Liu X, Finizio S, Raabe J, Lee NJ, Kim SI, Park SY, Kim Y, Kim JY, Lee D, Lee O, Choi JW, Min BC, Koo HC, Chang J. Current-driven dynamics and inhibition of the skyrmion Hall effect of ferrimagnetic skyrmions in GdFeCo films. Nat Commun 2018; 9:959. [PMID: 29511179 PMCID: PMC5840382 DOI: 10.1038/s41467-018-03378-7] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [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: 06/13/2017] [Accepted: 02/05/2018] [Indexed: 11/30/2022] Open
Abstract
Magnetic skyrmions are swirling magnetic textures with novel characteristics suitable for future spintronic and topological applications. Recent studies confirmed the room-temperature stabilization of skyrmions in ultrathin ferromagnets. However, such ferromagnetic skyrmions show an undesirable topological effect, the skyrmion Hall effect, which leads to their current-driven motion towards device edges, where skyrmions could easily be annihilated by topographic defects. Recent theoretical studies have predicted enhanced current-driven behavior for antiferromagnetically exchange-coupled skyrmions. Here we present the stabilization of these skyrmions and their current-driven dynamics in ferrimagnetic GdFeCo films. By utilizing element-specific X-ray imaging, we find that the skyrmions in the Gd and FeCo sublayers are antiferromagnetically exchange-coupled. We further confirm that ferrimagnetic skyrmions can move at a velocity of ~50 m s−1 with reduced skyrmion Hall angle, |θSkHE| ~ 20°. Our findings open the door to ferrimagnetic and antiferromagnetic skyrmionics while providing key experimental evidences of recent theoretical studies. Non-zero topological charge prevents the straight motion of ferromagnetic skyrmions and hinders their applications. Here, the authors report the stabilization and current-driven dynamics of skyrmions in GdFeCo films in which the ferrimagnetic skyrmions can move with high velocity and reduced skyrmion Hall angle.
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Affiliation(s)
- Seonghoon Woo
- Center for Spintronics, Korea Institute of Science and Technology, Seoul, 02792, Korea.
| | - Kyung Mee Song
- Center for Spintronics, Korea Institute of Science and Technology, Seoul, 02792, Korea.,Department of Physics, Sookmyung Women's University, Seoul, 04130, Korea
| | - Xichao Zhang
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, 518172, China
| | - Yan Zhou
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, 518172, China
| | - Motohiko Ezawa
- Department of Applied Physics, University of Tokyo, Hongo 7-3-1, Tokyo, 113-8656, Japan
| | - Xiaoxi Liu
- Department of Electrical and Computer Engineering, Shinshu University, Wakasato 4-17-1, Nagano, 380-8553, Japan
| | - S Finizio
- Swiss Light Source, Paul Scherrer Institut, 5232, Villigen, Switzerland
| | - J Raabe
- Swiss Light Source, Paul Scherrer Institut, 5232, Villigen, Switzerland
| | - Nyun Jong Lee
- Spin Engineering Physics Team, Division of Scientific Instrumentation, Korea Basic Science Institute, Daejeon, 305-806, Korea
| | - Sang-Il Kim
- Spin Engineering Physics Team, Division of Scientific Instrumentation, Korea Basic Science Institute, Daejeon, 305-806, Korea
| | - Seung-Young Park
- Spin Engineering Physics Team, Division of Scientific Instrumentation, Korea Basic Science Institute, Daejeon, 305-806, Korea
| | - Younghak Kim
- Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang, 37673, Korea
| | - Jae-Young Kim
- Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang, 37673, Korea
| | - Dongjoon Lee
- Center for Spintronics, Korea Institute of Science and Technology, Seoul, 02792, Korea.,KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02481, Korea
| | - OukJae Lee
- Center for Spintronics, Korea Institute of Science and Technology, Seoul, 02792, Korea
| | - Jun Woo Choi
- Center for Spintronics, Korea Institute of Science and Technology, Seoul, 02792, Korea.,Department of Nanomaterials Science and Engineering, Korea University of Science and Technology, Daejeon, 34113, Korea
| | - Byoung-Chul Min
- Center for Spintronics, Korea Institute of Science and Technology, Seoul, 02792, Korea.,Department of Nanomaterials Science and Engineering, Korea University of Science and Technology, Daejeon, 34113, Korea
| | - Hyun Cheol Koo
- Center for Spintronics, Korea Institute of Science and Technology, Seoul, 02792, Korea.,KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02481, Korea
| | - Joonyeon Chang
- Center for Spintronics, Korea Institute of Science and Technology, Seoul, 02792, Korea.,Department of Nanomaterials Science and Engineering, Korea University of Science and Technology, Daejeon, 34113, Korea
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33
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Zeissler K, Mruczkiewicz M, Finizio S, Raabe J, Shepley PM, Sadovnikov AV, Nikitov SA, Fallon K, McFadzean S, McVitie S, Moore TA, Burnell G, Marrows CH. Pinning and hysteresis in the field dependent diameter evolution of skyrmions in Pt/Co/Ir superlattice stacks. Sci Rep 2017; 7:15125. [PMID: 29123144 PMCID: PMC5680206 DOI: 10.1038/s41598-017-15262-3] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [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: 06/22/2017] [Accepted: 10/17/2017] [Indexed: 11/09/2022] Open
Abstract
We have imaged Néel skyrmion bubbles in perpendicularly magnetised polycrystalline multilayers patterned into 1 µm diameter dots, using scanning transmission x-ray microscopy. The skyrmion bubbles can be nucleated by the application of an external magnetic field and are stable at zero field with a diameter of 260 nm. Applying an out of plane field that opposes the magnetisation of the skyrmion bubble core moment applies pressure to the bubble and gradually compresses it to a diameter of approximately 100 nm. On removing the field the skyrmion bubble returns to its original diameter via a hysteretic pathway where most of the expansion occurs in a single abrupt step. This contradicts analytical models of homogeneous materials in which the skyrmion compression and expansion are reversible. Micromagnetic simulations incorporating disorder can explain this behaviour using an effective thickness modulation between 10 nm grains.
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Affiliation(s)
- K Zeissler
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, United Kingdom.
| | - M Mruczkiewicz
- Institute of Electrical Engineering, Slovak Academy of Sciences, Dúbravská cesta 9, 841 04, Bratislava, Slovak Republic
| | - S Finizio
- Swiss Light Source, Paul Scherrer Institute, 5232, Villigen, Switzerland
| | - J Raabe
- Swiss Light Source, Paul Scherrer Institute, 5232, Villigen, Switzerland
| | - P M Shepley
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - A V Sadovnikov
- Laboratory "Metamaterials", Saratov State University, Saratov, 410012, Russia.,Kotel'nikov Institute of Radioengineering and Electronics, Russian Academy of Sciences, Moscow, 125009, Russia
| | - S A Nikitov
- Laboratory "Metamaterials", Saratov State University, Saratov, 410012, Russia.,Kotel'nikov Institute of Radioengineering and Electronics, Russian Academy of Sciences, Moscow, 125009, Russia
| | - K Fallon
- School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
| | - S McFadzean
- School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
| | - S McVitie
- School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
| | - T A Moore
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - G Burnell
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - C H Marrows
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, United Kingdom
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34
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Baumgartner M, Garello K, Mendil J, Avci CO, Grimaldi E, Murer C, Feng J, Gabureac M, Stamm C, Acremann Y, Finizio S, Wintz S, Raabe J, Gambardella P. Spatially and time-resolved magnetization dynamics driven by spin-orbit torques. Nat Nanotechnol 2017; 12:980-986. [PMID: 28825713 DOI: 10.1038/nnano.2017.151] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 06/28/2017] [Indexed: 06/07/2023]
Abstract
Current-induced spin-orbit torques are one of the most effective ways to manipulate the magnetization in spintronic devices, and hold promise for fast switching applications in non-volatile memory and logic units. Here, we report the direct observation of spin-orbit-torque-driven magnetization dynamics in Pt/Co/AlOx dots during current pulse injection. Time-resolved X-ray images with 25 nm spatial and 100 ps temporal resolution reveal that switching is achieved within the duration of a subnanosecond current pulse by the fast nucleation of an inverted domain at the edge of the dot and propagation of a tilted domain wall across the dot. The nucleation point is deterministic and alternates between the four dot quadrants depending on the sign of the magnetization, current and external field. Our measurements reveal how the magnetic symmetry is broken by the concerted action of the damping-like and field-like spin-orbit torques and the Dzyaloshinskii-Moriya interaction, and show that reproducible switching events can be obtained for over 1012 reversal cycles.
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Affiliation(s)
| | - Kevin Garello
- Department of Materials, ETH Zürich, 8093 Zürich, Switzerland
- IMEC, Kapeldreef 75, 3001 Leuven, Belgium
| | - Johannes Mendil
- Department of Materials, ETH Zürich, 8093 Zürich, Switzerland
| | - Can Onur Avci
- Department of Materials, ETH Zürich, 8093 Zürich, Switzerland
| | - Eva Grimaldi
- Department of Materials, ETH Zürich, 8093 Zürich, Switzerland
| | - Christoph Murer
- Department of Materials, ETH Zürich, 8093 Zürich, Switzerland
| | - Junxiao Feng
- Department of Materials, ETH Zürich, 8093 Zürich, Switzerland
| | - Mihai Gabureac
- Department of Materials, ETH Zürich, 8093 Zürich, Switzerland
| | - Christian Stamm
- Department of Materials, ETH Zürich, 8093 Zürich, Switzerland
| | - Yves Acremann
- Laboratory for Solid State Physics, ETH Zürich, 8093 Zürich, Switzerland
| | | | | | - Jörg Raabe
- Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
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35
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Foerster M, Macià F, Statuto N, Finizio S, Hernández-Mínguez A, Lendínez S, Santos PV, Fontcuberta J, Hernàndez JM, Kläui M, Aballe L. Direct imaging of delayed magneto-dynamic modes induced by surface acoustic waves. Nat Commun 2017; 8:407. [PMID: 28864819 PMCID: PMC5581333 DOI: 10.1038/s41467-017-00456-0] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [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: 12/05/2016] [Accepted: 06/30/2017] [Indexed: 11/24/2022] Open
Abstract
The magnetoelastic effect—the change of magnetic properties caused by the elastic deformation of a magnetic material—has been proposed as an alternative approach to magnetic fields for the low-power control of magnetization states of nanoelements since it avoids charge currents, which entail ohmic losses. Here, we have studied the effect of dynamic strain accompanying a surface acoustic wave on magnetic nanostructures in thermal equilibrium. We have developed an experimental technique based on stroboscopic X-ray microscopy that provides a pathway to the quantitative study of strain waves and magnetization at the nanoscale. We have simultaneously imaged the evolution of both strain and magnetization dynamics of nanostructures at the picosecond time scale and found that magnetization modes have a delayed response to the strain modes, adjustable by the magnetic domain configuration. Our results provide fundamental insight into magnetoelastic coupling in nanostructures and have implications for the design of strain-controlled magnetostrictive nano-devices. Understanding the effects of local dynamic strain on magnetization may help the development of magnetic devices. Foerster et al. demonstrate stroboscopic imaging that allows the observation of both strain and magnetization dynamics in nickel when surface acoustic waves are driven in the substrate.
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Affiliation(s)
- Michael Foerster
- ALBA Synchrotron Light Source, 08290, Cerdanyola del Valles, Spain
| | - Ferran Macià
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, 08193, Bellaterra, Spain. .,Dept. of Condensed Matter Physics, University of Barcelona, 08028, Barcelona, Spain.
| | - Nahuel Statuto
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, 08193, Bellaterra, Spain.,Dept. of Condensed Matter Physics, University of Barcelona, 08028, Barcelona, Spain
| | - Simone Finizio
- Institut für Physik, Johannes Gutenberg Universität Mainz, 55099, Mainz, Germany.,Swiss Light Source, Paul Scherrer Institut, CH-5232, Villigen PSI, Switzerland
| | | | - Sergi Lendínez
- Dept. of Condensed Matter Physics, University of Barcelona, 08028, Barcelona, Spain
| | - Paulo V Santos
- Paul-Drude-Institut fur Festkörperelektronik, Hausvogteiplatz 5-7, 10117, Berlin, Germany
| | - Josep Fontcuberta
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, 08193, Bellaterra, Spain
| | - Joan Manel Hernàndez
- Dept. of Condensed Matter Physics, University of Barcelona, 08028, Barcelona, Spain
| | - Mathias Kläui
- Institut für Physik, Johannes Gutenberg Universität Mainz, 55099, Mainz, Germany
| | - Lucia Aballe
- ALBA Synchrotron Light Source, 08290, Cerdanyola del Valles, Spain
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36
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Finizio S, Wintz S, Kirk E, Raabe J. In situ membrane bending setup for strain-dependent scanning transmission x-ray microscopy investigations. Rev Sci Instrum 2016; 87:123703. [PMID: 28040922 DOI: 10.1063/1.4971849] [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] [Indexed: 06/06/2023]
Abstract
We present a setup that allows for the in situ generation of tensile strains by bending x-ray transparent Si3N4 membranes with the application of a pressure difference between the two sides of the membrane, enabling the possibility to employ high resolution space- and time-resolved scanning transmission x-ray microscopy for the investigation of the magneto-elastic coupling.
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Affiliation(s)
- S Finizio
- Paul Scherrer Institut, Villigen, CH-5232, Switzerland
| | - S Wintz
- Paul Scherrer Institut, Villigen, CH-5232, Switzerland
| | - E Kirk
- Paul Scherrer Institut, Villigen, CH-5232, Switzerland
| | - J Raabe
- Paul Scherrer Institut, Villigen, CH-5232, Switzerland
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37
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Finizio S, Foerster M, Krüger B, Vaz CAF, Miyawaki T, Mawass MA, Peña L, Méchin L, Hühn S, Moshnyaga V, Büttner F, Bisig A, Le Guyader L, El Moussaoui S, Valencia S, Kronast F, Eisebitt S, Kläui M. Domain wall transformations and hopping in La(0.7)Sr(0.3)MnO(3) nanostructures imaged with high resolution x-ray magnetic microscopy. J Phys Condens Matter 2014; 26:456003. [PMID: 25336527 DOI: 10.1088/0953-8984/26/45/456003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We investigate the effect of electric current pulse injection on domain walls in La(0.7)Sr(0.3)MnO(3) (LSMO) half-ring nanostructures by high resolution x-ray magnetic microscopy at room temperature. Due to the easily accessible Curie temperature of LSMO, we can employ reasonable current densities to induce the Joule heating necessary to observe effects such as hopping of the domain walls between different pinning sites and nucleation/annihilation events. Such effects are the dominant features close to the Curie temperature, while spin torque is found to play a small role close to room temperature. We are also able to observe thermally activated domain wall transformations and we find that, for the analyzed geometries, the vortex domain wall configuration is energetically favored, in agreement with micromagnetic simulations.
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Affiliation(s)
- S Finizio
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, 55128 Mainz, Germany
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38
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Abstract
The effects of accurate and erroneous feedback on magnitude of illusion for the Müller-Lyer illusion were examined. The provision of accurate feedback substantially reduced the magnitude of the Müller-Lyer illusion whereas the influences of inaccurate feedback were dependent upon whether subjects were prompted to overestimate or to underestimate the length of the comparison line.
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Affiliation(s)
- G M Brosvic
- Department of Psychology, Rider University, Lawrenceville, New Jersey 08648, USA
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