1
|
Weinert P, Hochhaus J, Kesper L, Appel R, Hilgers S, Schmitz M, Schulte M, Hönig R, Kronast F, Valencia S, Kruskopf M, Chatterjee A, Berges U, Westphal C. Structural, chemical, and magnetic investigation of a graphene/cobalt/platinum multilayer system on silicon carbide. Nanotechnology 2024; 35:165702. [PMID: 38211321 DOI: 10.1088/1361-6528/ad1d7b] [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] [Received: 07/28/2023] [Accepted: 01/11/2024] [Indexed: 01/13/2024]
Abstract
We investigate the magnetic interlayer coupling and domain structure of ultra-thin ferromagnetic (FM) cobalt (Co) layers embedded between a graphene (G) layer and a platinum (Pt) layer on a silicon carbide (SiC) substrate (G/Co/Pt on SiC). Experimentally, a combination of x-ray photoemission electron microscopy with x-ray magnetic circular dichroism has been carried out at the Co L-edge. Furthermore, structural and chemical properties of the system have been investigated using low energy electron diffraction (LEED) and x-ray photoelectron spectroscopy (XPS).In situLEED patterns revealed the crystalline structure of each layer within the system. Moreover, XPS confirmed the presence of quasi-freestanding graphene, the absence of cobalt silicide, and the appearance of two silicon carbide surface components due to Pt intercalation. Thus, the Pt-layer effectively functions as a diffusion barrier. The magnetic structure of the system was unaffected by the substrate's step structure. Furthermore, numerous vortices and anti-vortices were found in all samples, distributed all over the surfaces, indicating Dzyaloshinskii-Moriya interaction. Only regions with a locally increased Co-layer thickness showed no vortices. Moreover, unlike in similar systems, the magnetization was predominantly in-plane, so no perpendicular magnetic anisotropy was found.
Collapse
Affiliation(s)
- P Weinert
- Fakultät Physik/DELTA, TU Dortmund University, D-44221 Dortmund, Germany
| | - J Hochhaus
- Fakultät Physik/DELTA, TU Dortmund University, D-44221 Dortmund, Germany
| | - L Kesper
- Fakultät Physik/DELTA, TU Dortmund University, D-44221 Dortmund, Germany
| | - R Appel
- Fakultät Physik/DELTA, TU Dortmund University, D-44221 Dortmund, Germany
| | - S Hilgers
- Fakultät Physik/DELTA, TU Dortmund University, D-44221 Dortmund, Germany
| | - M Schmitz
- Fakultät Physik/DELTA, TU Dortmund University, D-44221 Dortmund, Germany
| | - M Schulte
- Fakultät Physik/DELTA, TU Dortmund University, D-44221 Dortmund, Germany
| | - R Hönig
- Fakultät Physik/DELTA, TU Dortmund University, D-44221 Dortmund, Germany
| | - F Kronast
- Helmholtz-Zentrum Berlin für Materialien und Energie, D-12489 Berlin, Germany
| | - S Valencia
- Helmholtz-Zentrum Berlin für Materialien und Energie, D-12489 Berlin, Germany
| | - M Kruskopf
- Physikalisch-Technische Bundesanstalt (PTB), D-38116 Braunschweig, Germany
| | - A Chatterjee
- Physikalisch-Technische Bundesanstalt (PTB), D-38116 Braunschweig, Germany
| | - U Berges
- Fakultät Physik/DELTA, TU Dortmund University, D-44221 Dortmund, Germany
| | - C Westphal
- Fakultät Physik/DELTA, TU Dortmund University, D-44221 Dortmund, Germany
| |
Collapse
|
2
|
López-Flores V, Mawass MA, Herrero-Albillos J, Uenal AA, Valencia S, Kronast F, Boeglin C. A local view of the laser induced magnetic domain dynamics in CoPd stripe domains at the picosecond time scale. J Phys Condens Matter 2020; 32:465801. [PMID: 32610298 DOI: 10.1088/1361-648x/aba1ac] [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: 06/11/2023]
Abstract
The dynamics of the magnetic structure in a well ordered ferromagnetic CoPd stripe domain pattern has been investigated upon excitation by femtosecond infrared laser pulses. Time-resolved x-ray magnetic circular dichroism in photoemission electron microscopy (TR-XMCD-PEEM) is used to perform real space magnetic imaging with 100 ps time resolution in order to show local transformations of the domains structures. Using the time resolution of the synchrotron radiation facility of the Helmholtz-Zentrum Berlin, we are able to image the transient magnetic domains in a repetitive pump and probe experiment. In this work, we study the reversible and irreversible transformations of the excited magnetic stripe domains as function of the laser fluence. Our results can be explained by thermal contributions, reducing the XMCD amplitude in each stripe domain below a threshold fluence of 12 mJ cm-2. Above this threshold fluence, irreversible transformations of the magnetic domains are observed. Static XMCD-PEEM images reveal the new partially ordered stripe domain structures characterized by a new local magnetic domain distribution showing an organized pattern at the micrometer scale. This new arrangement is attributed to the recovery of the magnetic anisotropy during heat dissipation under an Oersted field.
Collapse
Affiliation(s)
- V López-Flores
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, F-67000 Strasbourg, France
| | | | | | | | | | | | | |
Collapse
|
3
|
Baldrati L, Gomonay O, Ross A, Filianina M, Lebrun R, Ramos R, Leveille C, Fuhrmann F, Forrest TR, Maccherozzi F, Valencia S, Kronast F, Saitoh E, Sinova J, Kläui M. Mechanism of Néel Order Switching in Antiferromagnetic Thin Films Revealed by Magnetotransport and Direct Imaging. Phys Rev Lett 2019; 123:177201. [PMID: 31702247 DOI: 10.1103/physrevlett.123.177201] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 08/07/2019] [Indexed: 06/10/2023]
Abstract
We probe the current-induced magnetic switching of insulating antiferromagnet-heavy-metal systems, by electrical spin Hall magnetoresistance measurements and direct imaging, identifying a reversal occurring by domain wall (DW) motion. We observe switching of more than one-third of the antiferromagnetic domains by the application of current pulses. Our data reveal two different magnetic switching mechanisms leading together to an efficient switching, namely, the spin-current induced effective magnetic anisotropy variation and the action of the spin torque on the DWs.
Collapse
Affiliation(s)
- L Baldrati
- Institute of Physics, Johannes Gutenberg-University Mainz, 55128 Mainz, Germany
| | - O Gomonay
- Institute of Physics, Johannes Gutenberg-University Mainz, 55128 Mainz, Germany
| | - A Ross
- Institute of Physics, Johannes Gutenberg-University Mainz, 55128 Mainz, Germany
- Graduate School of Excellence Materials Science in Mainz, 55128 Mainz, Germany
| | - M Filianina
- Institute of Physics, Johannes Gutenberg-University Mainz, 55128 Mainz, Germany
- Graduate School of Excellence Materials Science in Mainz, 55128 Mainz, Germany
| | - R Lebrun
- Institute of Physics, Johannes Gutenberg-University Mainz, 55128 Mainz, Germany
| | - R Ramos
- WPI-Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
| | - C Leveille
- Institute of Physics, Johannes Gutenberg-University Mainz, 55128 Mainz, Germany
| | - F Fuhrmann
- Institute of Physics, Johannes Gutenberg-University Mainz, 55128 Mainz, Germany
| | - T R Forrest
- Diamond Light Source, Chilton, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - F Maccherozzi
- Diamond Light Source, Chilton, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - S Valencia
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, D-12489 Berlin, Germany
| | - F Kronast
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, D-12489 Berlin, Germany
| | - E Saitoh
- WPI-Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
- Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
- Advanced Science Research Center, Japan Atomic Energy Agency, Tokai 319-1195, Japan
- Center for Spintronics Research Network, Tohoku University, Sendai 980-8577, Japan
- Department of Applied Physics, The University of Tokyo, Tokyo 113-8656, Japan
| | - J Sinova
- Institute of Physics, Johannes Gutenberg-University Mainz, 55128 Mainz, Germany
| | - M Kläui
- Institute of Physics, Johannes Gutenberg-University Mainz, 55128 Mainz, Germany
- Graduate School of Excellence Materials Science in Mainz, 55128 Mainz, Germany
| |
Collapse
|
4
|
Ünal AA, Parabas A, Arora A, Ehrler J, Barton C, Valencia S, Bali R, Thomson T, Yildiz F, Kronast F. Laser-driven formation of transient local ferromagnetism in FeRh thin films. Ultramicroscopy 2017; 183:104-108. [PMID: 28396080 DOI: 10.1016/j.ultramic.2017.03.024] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 02/13/2017] [Accepted: 03/22/2017] [Indexed: 10/19/2022]
Abstract
The antiferromagnetic to ferromagnetic phase transition in FeRh can be induced globally by either heating the material above its phase transition temperature or applying a combination of external stimuli (such as mechanical strain, electric/magnetic fields) on the material preheated close to its transition temperature. On the other hand, to locally induce this phase transition is more desirable for applications and requires a confined source of energy such as a focused laser beam. Here we combine laser excitation with X-ray magnetic imaging to determine the effect of laser heating on the local and transient magnetization of FeRh using time-resolved photoelectron emission microscopy. Excitation by an ultrashort laser pulse generates a local ferromagnetic state within 0.6ns which recovers its initial antiferromagnetic state after a further 2ns. The form of the domains during the growth and diminution of ferromagnetic ordering suggests an intrinsic speed limit for magnetic and structural changes.
Collapse
Affiliation(s)
- A A Ünal
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Str. 15, D-12489 Berlin, Germany.
| | - A Parabas
- Gebze Teknik Üniversitesi, Temel Bilimler Fakültesi, Fizik Bölümü, TR-41400 Gebze/Kocaeli, Turkey
| | - A Arora
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Str. 15, D-12489 Berlin, Germany
| | - J Ehrler
- Institut für Ionenstrahlphysik und Materialforschung, Helmholtz-Zentrum Dresden-Rossendorf, D-01328 Dresden, Germany
| | - C Barton
- School of Computer Science, University of Manchester, Manchester M13 9PL, United Kingdom
| | - S Valencia
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Str. 15, D-12489 Berlin, Germany
| | - R Bali
- Institut für Ionenstrahlphysik und Materialforschung, Helmholtz-Zentrum Dresden-Rossendorf, D-01328 Dresden, Germany
| | - T Thomson
- School of Computer Science, University of Manchester, Manchester M13 9PL, United Kingdom
| | - F Yildiz
- Gebze Teknik Üniversitesi, Temel Bilimler Fakültesi, Fizik Bölümü, TR-41400 Gebze/Kocaeli, Turkey
| | - F Kronast
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Str. 15, D-12489 Berlin, Germany.
| |
Collapse
|
5
|
Gierster L, Pape L, Ünal AA, Kronast F. A sample holder with integrated laser optics for an ELMITEC photoemission electron microscope. Rev Sci Instrum 2015; 86:023702. [PMID: 25725847 DOI: 10.1063/1.4907402] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We present a new sample holder compatible with ELMITEC Photoemission Electron Microscopes (PEEMs) containing an optical lens and a mirror. With the integrated optical elements, a laser beam is focused from the back side of the sample at normal incidence, yielding a minimum spot size of about 1 μm. This opens up new possibilities for local laser excitations in PEEM experiments such as imaging all-optical magnetization switching at a small length scale.
Collapse
Affiliation(s)
- L Gierster
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein Str. 15, 12489 Berlin, Germany
| | - L Pape
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein Str. 15, 12489 Berlin, Germany
| | - A A Ünal
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein Str. 15, 12489 Berlin, Germany
| | - F Kronast
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein Str. 15, 12489 Berlin, Germany
| |
Collapse
|
6
|
Gerlach D, Wimmer M, Wilks RG, Félix R, Kronast F, Ruske F, Bär M. The complex interface chemistry of thin-film silicon/zinc oxide solar cell structures. Phys Chem Chem Phys 2014; 16:26266-72. [PMID: 25363298 DOI: 10.1039/c4cp03364g] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The interface between solid-phase crystallized phosphorous-doped polycrystalline silicon (poly-Si(n(+))) and aluminum-doped zinc oxide (ZnO:Al) was investigated using spatially resolved photoelectron emission microscopy. We find the accumulation of aluminum in the proximity of the interface. Based on a detailed photoemission line analysis, we also suggest the formation of an interface species. Silicon suboxide and/or dehydrated hemimorphite have been identified as likely candidates. For each scenario a detailed chemical reaction pathway is suggested. The chemical instability of the poly-Si(n(+))/ZnO:Al interface is explained by the fact that SiO2 is more stable than ZnO and/or that H2 is released from the initially deposited a-Si:H during the crystallization process. As a result, Zn (a deep acceptor in silicon) is "liberated" close to the silicon/zinc oxide interface presenting the inherent risk of forming deep defects in the silicon absorber. These could act as recombination centers and thus limit the performance of silicon/zinc oxide based solar cells. Based on this insight some recommendations with respect to solar cell design, material selection, and process parameters are given for further knowledge-based thin-film silicon device optimization.
Collapse
Affiliation(s)
- D Gerlach
- Renewable Energies, Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, D-14109 Berlin, Germany.
| | | | | | | | | | | | | |
Collapse
|
7
|
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.
Collapse
Affiliation(s)
- S Finizio
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, 55128 Mainz, Germany
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Cherifi RO, Ivanovskaya V, Phillips LC, Zobelli A, Infante IC, Jacquet E, Garcia V, Fusil S, Briddon PR, Guiblin N, Mougin A, Ünal AA, Kronast F, Valencia S, Dkhil B, Barthélémy A, Bibes M. Electric-field control of magnetic order above room temperature. Nat Mater 2014; 13:345-351. [PMID: 24464245 DOI: 10.1038/nmat3870] [Citation(s) in RCA: 121] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Accepted: 12/18/2013] [Indexed: 06/03/2023]
Abstract
Controlling magnetism by means of electric fields is a key issue for the future development of low-power spintronics. Progress has been made in the electrical control of magnetic anisotropy, domain structure, spin polarization or critical temperatures. However, the ability to turn on and off robust ferromagnetism at room temperature and above has remained elusive. Here we use ferroelectricity in BaTiO3 crystals to tune the sharp metamagnetic transition temperature of epitaxially grown FeRh films and electrically drive a transition between antiferromagnetic and ferromagnetic order with only a few volts, just above room temperature. The detailed analysis of the data in the light of first-principles calculations indicate that the phenomenon is mediated by both strain and field effects from the BaTiO3. Our results correspond to a magnetoelectric coupling larger than previous reports by at least one order of magnitude and open new perspectives for the use of ferroelectrics in magnetic storage and spintronics.
Collapse
Affiliation(s)
- R O Cherifi
- 1] Unité Mixte de Physique CNRS/Thales, 1 av. Fresnel, 91767 Palaiseau & Université Paris-Sud, Orsay 91405, France [2]
| | - V Ivanovskaya
- Unité Mixte de Physique CNRS/Thales, 1 av. Fresnel, 91767 Palaiseau & Université Paris-Sud, Orsay 91405, France
| | - L C Phillips
- Unité Mixte de Physique CNRS/Thales, 1 av. Fresnel, 91767 Palaiseau & Université Paris-Sud, Orsay 91405, France
| | - A Zobelli
- Laboratoire de Physique des Solides, Université Paris-Sud, CNRS UMR 8502, Orsay 91405, France
| | - I C Infante
- Laboratoire SPMS, UMR 8580, Ecole Centrale Paris-CNRS, Grande voie des vignes, Châtenay-Malabry 92290, France
| | - E Jacquet
- Unité Mixte de Physique CNRS/Thales, 1 av. Fresnel, 91767 Palaiseau & Université Paris-Sud, Orsay 91405, France
| | - V Garcia
- Unité Mixte de Physique CNRS/Thales, 1 av. Fresnel, 91767 Palaiseau & Université Paris-Sud, Orsay 91405, France
| | - S Fusil
- 1] Unité Mixte de Physique CNRS/Thales, 1 av. Fresnel, 91767 Palaiseau & Université Paris-Sud, Orsay 91405, France [2] Université d'Evry-Val d'Essonne, Bd. F. Mitterrand, Evry cedex 91025, France
| | - P R Briddon
- School of Electrical and Electronic Engineering, University of Newcastle, Newcastle upon Tyne, NE 1 7RU, UK
| | - N Guiblin
- Laboratoire SPMS, UMR 8580, Ecole Centrale Paris-CNRS, Grande voie des vignes, Châtenay-Malabry 92290, France
| | - A Mougin
- Laboratoire de Physique des Solides, Université Paris-Sud, CNRS UMR 8502, Orsay 91405, France
| | - A A Ünal
- Helmholtz-Zentrum Berlin für Materialen und Energie, Albert-Einstein-Strasse 15, Berlin 12489, Germany
| | - F Kronast
- Helmholtz-Zentrum Berlin für Materialen und Energie, Albert-Einstein-Strasse 15, Berlin 12489, Germany
| | - S Valencia
- Helmholtz-Zentrum Berlin für Materialen und Energie, Albert-Einstein-Strasse 15, Berlin 12489, Germany
| | - B Dkhil
- Laboratoire SPMS, UMR 8580, Ecole Centrale Paris-CNRS, Grande voie des vignes, Châtenay-Malabry 92290, France
| | - A Barthélémy
- Unité Mixte de Physique CNRS/Thales, 1 av. Fresnel, 91767 Palaiseau & Université Paris-Sud, Orsay 91405, France
| | - M Bibes
- Unité Mixte de Physique CNRS/Thales, 1 av. Fresnel, 91767 Palaiseau & Université Paris-Sud, Orsay 91405, France
| |
Collapse
|
9
|
Castán-Guerrero C, Sesé J, Bartolomé J, Bartolomé F, Herrero-Albillos J, Kronast F, Strichovanec P, Merazzo KJ, Vázquez M, Vavassori P, García LM. Fabrication and magnetic characterization of cobalt antidot arrays: effect of the surrounding continuous film. J Nanosci Nanotechnol 2012; 12:7437-7441. [PMID: 23035490 DOI: 10.1166/jnn.2012.6537] [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: 06/01/2023]
Abstract
We have performed an experimental study on the influence of a ferromagnetic continuous film in the magnetization reversal processes in discrete submicrometric antidot arrays fabricated on it. In order to compare the magnetic properties, two sets of antidot arrays have been fabricated over a cobalt thin film: embedded in the continuous film, and isolated by a trench surrounding the array. X-ray photoemission electron microscopy images of the virgin state show the same magnetic domain distribution in both sets of samples, finding no evidence of any effect of the surrounding film. This result is supported by the hysteresis loops measured with magneto-optical Kerr effect, as isolated and non-isolated arrays present almost coincident loops. A huge increase of the coercivity of the film is achieved, and the expected dependence on the geometrical parameters of the array is found, connecting the previous studies on the micro- and nanometric scales.
Collapse
Affiliation(s)
- C Castán-Guerrero
- Instituto de Ciencia de Materiales de Aragón (ICMA) and Departamento de Física de la Materia Condensada, Consejo Superior de Investigaciones Científicas-Universidad de Zaragoza, C/Pedro Cerbuna 12, 50009 Zaragoza, Spain
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Seemann KM, Garcia-Sanchez F, Kronast F, Miguel J, Kákay A, Schneider CM, Hertel R, Freimuth F, Mokrousov Y, Blügel S. Disentangling the physical contributions to the electrical resistance in magnetic domain walls: a multiscale study. Phys Rev Lett 2012; 108:077201. [PMID: 22401245 DOI: 10.1103/physrevlett.108.077201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Indexed: 05/31/2023]
Abstract
We analyze the origin of the electrical resistance arising in domain walls of perpendicularly magnetized materials by considering a superposition of anisotropic magnetoresistance and the resistance implied by the magnetization chirality. The domain wall profiles of L1(0)-FePd and L1(0)-FePt are determined by micromagnetic simulations based on which we perform first-principles calculations to quantify electron transport through the core and closure region of the walls. The wall resistance, being twice as high in L1(0)-FePd than in L1(0)-FePt, is found to be clearly dominated in both cases by a high gradient of magnetization rotation, which agrees well with experimental observations.
Collapse
Affiliation(s)
- K M Seemann
- Peter Grünberg Institute, Forschungszentrum Jülich and Jülich-Aachen Research Alliance, Jülich, Germany.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
11
|
Antoniak C, Friedenberger N, Trunova A, Meckenstock R, Kronast F, Fauth K, Farle M, Wende H. Intrinsic Magnetism and Collective Magnetic Properties of Size-Selected Nanoparticles. Nanoparticles from the Gasphase 2012. [DOI: 10.1007/978-3-642-28546-2_11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
|
12
|
Schirmer M, Walz MM, Papp C, Kronast F, Gray AX, Balke B, Cramm S, Fadley CS, Steinrück HP, Marbach H. Fabrication of layered nanostructures by successive electron beam induced deposition with two precursors: protective capping of metallic iron structures. Nanotechnology 2011; 22:475304. [PMID: 22057093 DOI: 10.1088/0957-4484/22/47/475304] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We report on the stepwise generation of layered nanostructures via electron beam induced deposition (EBID) using organometallic precursor molecules in ultra-high vacuum (UHV). In a first step a metallic iron line structure was produced using iron pentacarbonyl; in a second step this nanostructure was then locally capped with a 2-3 nm thin titanium oxide-containing film fabricated from titanium tetraisopropoxide. The chemical composition of the deposited layers was analyzed by spatially resolved Auger electron spectroscopy. With spatially resolved x-ray absorption spectroscopy at the Fe L₃ edge, it was demonstrated that the thin capping layer prevents the iron structure from oxidation upon exposure to air.
Collapse
Affiliation(s)
- M Schirmer
- Lehrstuhl für Physikalische Chemie II, Universität Erlangen-Nürnberg, Egerlandstraße 3, D-91058 Erlangen, Germany
| | | | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Heyne L, Rhensius J, Ilgaz D, Bisig A, Rüdiger U, Kläui M, Joly L, Nolting F, Heyderman LJ, Thiele JU, Kronast F. Direct determination of large spin-torque nonadiabaticity in vortex core dynamics. Phys Rev Lett 2010; 105:187203. [PMID: 21231132 DOI: 10.1103/physrevlett.105.187203] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2010] [Indexed: 05/30/2023]
Abstract
We use a pump-probe photoemission electron microscopy technique to image the displacement of vortex cores in Permalloy discs due to the spin-torque effect during current pulse injection. Exploiting the distinctly different symmetries of the spin torques and the Oersted-field torque with respect to the vortex spin structure we determine the torques unambiguously, and we quantify the amplitude of the strongly debated nonadiabatic spin torque. The nonadiabaticity parameter is found to be β=0.15±0.07, which is more than an order of magnitude larger than the damping constant α, pointing to strong nonadiabatic transport across the high magnetization gradient vortex spin structures.
Collapse
Affiliation(s)
- L Heyne
- Fachbereich Physik, Universität Konstanz, Universitätsstrasse 10, D-78457 Konstanz, Germany
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Seemann KM, Mokrousov Y, Aziz A, Miguel J, Kronast F, Kuch W, Blamire MG, Hindmarch AT, Hickey BJ, Souza I, Marrows CH. Spin-orbit strength driven crossover between intrinsic and extrinsic mechanisms of the anomalous hall effect in the epitaxial L1{0}-ordered ferromagnets FePd and FePt. Phys Rev Lett 2010; 104:076402. [PMID: 20366900 DOI: 10.1103/physrevlett.104.076402] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2009] [Indexed: 05/29/2023]
Abstract
We determine the composition of intrinsic as well as extrinsic contributions to the anomalous Hall effect (AHE) in the isoelectronic L1_{0} FePd and FePt alloys. We show that the AHE signal in our 30 nm thick epitaxially deposited films of FePd is mainly due to an extrinsic side jump, while in the epitaxial FePt films of the same thickness and degree of order the intrinsic contribution is dominating over the extrinsic mechanisms of the AHE. We relate this crossover to the difference in spin-orbit strength of Pt and Pd atoms and suggest that this phenomenon can be used for tuning the origins of the AHE in complex alloys.
Collapse
Affiliation(s)
- K M Seemann
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, United Kingdom.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Garcia V, Bibes M, Bocher L, Valencia S, Kronast F, Crassous A, Moya X, Enouz-Vedrenne S, Gloter A, Imhoff D, Deranlot C, Mathur ND, Fusil S, Bouzehouane K, Barthelemy A. Ferroelectric Control of Spin Polarization. Science 2010; 327:1106-10. [DOI: 10.1126/science.1184028] [Citation(s) in RCA: 584] [Impact Index Per Article: 41.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
|
16
|
Miguel J, Sánchez-Barriga J, Bayer D, Kurde J, Heitkamp B, Piantek M, Kronast F, Aeschlimann M, Dürr HA, Kuch W. Time-resolved magnetization dynamics of cross-tie domain walls in permalloy microstructures. J Phys Condens Matter 2009; 21:496001. [PMID: 21836205 DOI: 10.1088/0953-8984/21/49/496001] [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: 05/31/2023]
Abstract
We report on a picosecond time-resolved x-ray magnetic circular dichroic-photoelectron emission microscopy study of the evolution of the magnetization components of a microstructured permalloy platelet comprising three cross-tie domain walls. A laser-excited photoswitch has been used to apply a triangular 80 Oe, 160 ps magnetic pulse. Micromagnetic calculations agree well with the experimental results, both in time and frequency, illustrating the large angle precession in the magnetic domains with magnetization perpendicular to the applied pulse, and showing how the magnetic vortices revert their core magnetization while the antivortices remain unaffected.
Collapse
Affiliation(s)
- J Miguel
- Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany
| | | | | | | | | | | | | | | | | | | |
Collapse
|