1
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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. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024:e2311157. [PMID: 38402421 DOI: 10.1002/adma.202311157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [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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2
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Goodge B, Gonzalez O, Xie LS, Bediako DK. Consequences and Control of Multiscale Order/Disorder in Chiral Magnetic Textures. ACS NANO 2023; 17:19865-19876. [PMID: 37801330 PMCID: PMC10604074 DOI: 10.1021/acsnano.3c04203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 10/02/2023] [Indexed: 10/07/2023]
Abstract
Transition metal intercalated transition metal dichalcogenides (TMDs) are promising platforms for next-generation spintronic devices based on their wide range of electronic and magnetic phases, which can be tuned by varying the host lattice or intercalant's identity, stoichiometry, or spatial order. Some of these compounds host a chiral magnetic phase in which the helical winding of magnetic moments propagates along a high-symmetry crystalline axis. Previous studies have demonstrated that variation in intercalant concentrations can have a dramatic effect on the formation of chiral domains and ensemble magnetic properties. However, a systematic and comprehensive study of how atomic-scale order and disorder impact these chiral magnetic textures is so far lacking. Here, we leverage a combination of imaging modes in the (scanning) transmission electron microscope (S/TEM) to directly probe (dis)order across multiple length scales and show how subtle changes in the atomic lattice can tune the mesoscale spin textures and bulk magnetic response in Cr1/3NbS2, with direct implications for the fundamental understanding and technological implementation of such compounds.
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Affiliation(s)
- Berit
H. Goodge
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
- Max
Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - Oscar Gonzalez
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
| | - Lilia S. Xie
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
| | - D. Kwabena Bediako
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical
Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
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3
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Azhar M, Kravchuk VP, Garst M. Screw Dislocations in Chiral Magnets. PHYSICAL REVIEW LETTERS 2022; 128:157204. [PMID: 35499887 DOI: 10.1103/physrevlett.128.157204] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 12/23/2021] [Accepted: 02/28/2022] [Indexed: 06/14/2023]
Abstract
Helimagnets realize an effective lamellar ordering that supports disclination and dislocation defects. Here, we investigate the micromagnetic structure of screw dislocation lines in cubic chiral magnets using analytical and numerical methods. The far field of these dislocations is universal and classified by an integer strength ν that quantifies its Burgers vector. We demonstrate that a rich variety of dislocation-core structures can be realized even for the same strength ν. In particular, the magnetization at the core can be either smooth or singular. We present a specific example with ν=1 for which the core is composed of a chain of singular Bloch points. In general, screw dislocations carry a noninteger but finite skyrmion charge so that they can be efficiently manipulated by spin currents and should contribute to the topological Hall effect.
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Affiliation(s)
- Maria Azhar
- Institut für Theoretische Festkörperphysik, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
| | - Volodymyr P Kravchuk
- Institut für Theoretische Festkörperphysik, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
- Bogolyubov Institute for Theoretical Physics of National Academy of Sciences of Ukraine, 03143 Kyiv, Ukraine
| | - Markus Garst
- Institut für Theoretische Festkörperphysik, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
- Institute for Quantum Materials and Technology, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
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4
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Ishii Y, Nakao H, Mizumaki M, Wakabayashi Y, Arima TH, Yamasaki Y. Topological charge of soft X-ray vortex beam determined by inline holography. Sci Rep 2022; 12:1044. [PMID: 35058482 PMCID: PMC8776782 DOI: 10.1038/s41598-022-04933-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 01/03/2022] [Indexed: 11/11/2022] Open
Abstract
A Laguerre-Gaussian (LG) vortex beam having a spiral wavefront can be characterized by its topological charge (TC). The TC gives the number of times that the beam phase passes through the interval [Formula: see text] following a closed loop surrounding the propagation axis. Here, the TC spectra of soft X-ray vortex beams are acquired using the in-line holography technique, where interference between vortex waves produced from a fork grating and divergent waves from a Fresnel zone plate is observed as a holographic image. The analyses revealed the phase distributions and the TC for the LG vortex waves, which reflects topological number of the fork gratings, as well as for the Hermite-Gaussian (HG) mode waves generated from the other gratings. We also conducted a simulation of the present technique for pair annihilation of topological defects in a magnetic texture. These results may pave the way for development of probes capable of characterizing the topological numbers of magnetic defects.
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Affiliation(s)
- Yuta Ishii
- Department of Physics, Tohoku University, Sendai, 980-8578, Japan.
| | - Hironori Nakao
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tsukuba, 305-0801, Japan
| | - Masaichiro Mizumaki
- Japan Synchrotron Radiation Research Institute (JASRI/SPring-8), Sayo, 679-5198, Japan
| | | | - Taka-Hisa Arima
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
| | - Yuichi Yamasaki
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tsukuba, 305-0801, Japan
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
- Research and Services Division of Materials Data and Integrated System (MaDIS), National Institute for Materials Science (NIMS), Tsukuba, 305-0047, Japan
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5
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Stepanova M, Masell J, Lysne E, Schoenherr P, Köhler L, Paulsen M, Qaiumzadeh A, Kanazawa N, Rosch A, Tokura Y, Brataas A, Garst M, Meier D. Detection of Topological Spin Textures via Nonlinear Magnetic Responses. NANO LETTERS 2022; 22:14-21. [PMID: 34935368 PMCID: PMC8759079 DOI: 10.1021/acs.nanolett.1c02723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 11/29/2021] [Indexed: 06/14/2023]
Abstract
Topologically nontrivial spin textures, such as skyrmions and dislocations, display emergent electrodynamics and can be moved by spin currents over macroscopic distances. These unique properties and their nanoscale size make them excellent candidates for the development of next-generation race-track memory and unconventional computing. A major challenge for these applications and the investigation of nanoscale magnetic structures in general is the realization of suitable detection schemes. We study magnetic disclinations, dislocations, and domain walls in FeGe and reveal pronounced responses that distinguish them from the helimagnetic background. A combination of magnetic force microscopy (MFM) and micromagnetic simulations links the response to the local magnetic susceptibility, that is, characteristic changes in the spin texture driven by the MFM tip. On the basis of the findings, which we explain using nonlinear response theory, we propose a read-out scheme using superconducting microcoils, presenting an innovative approach for detecting topological spin textures and domain walls in device-relevant geometries.
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Affiliation(s)
- Mariia Stepanova
- Department
of Materials Science and Engineering, Norwegian
University of Science and Technology (NTNU), Trondheim 7491, Norway
- Center
for Quantum Spintronics, Department of Physics,
Norwegian University of Science and Technology (NTNU), Trondheim 7491, Norway
| | - Jan Masell
- RIKEN
Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - Erik Lysne
- Department
of Materials Science and Engineering, Norwegian
University of Science and Technology (NTNU), Trondheim 7491, Norway
- Center
for Quantum Spintronics, Department of Physics,
Norwegian University of Science and Technology (NTNU), Trondheim 7491, Norway
| | - Peggy Schoenherr
- School
of Materials Science and Engineering, University
of New South Wales, Sydney, Sydney New South Wales 2052, Australia
- ARC
Centre of Excellence in Future Low-Energy Electronics Technologies
(FLEET), UNSW Sydney, Sydney, NSW 2052, Australia
| | - Laura Köhler
- Institute
of Theoretical Solid State Physics, Karlsruhe
Institute of Technology, 76049 Karlsruhe, Germany
| | - Michael Paulsen
- Physikalisch-Technische
Bundesanstalt (PTB), Berlin 10587, Germany
| | - Alireza Qaiumzadeh
- Center
for Quantum Spintronics, Department of Physics,
Norwegian University of Science and Technology (NTNU), Trondheim 7491, Norway
| | - Naoya Kanazawa
- Department
of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan
| | - Achim Rosch
- Institute
for Theoretical Physics, University of Cologne, Cologne 50937, Germany
| | - Yoshinori Tokura
- RIKEN
Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
- Department
of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan
- Tokyo
College, University of Tokyo, Tokyo 113−8656, Japan
| | - Arne Brataas
- Center
for Quantum Spintronics, Department of Physics,
Norwegian University of Science and Technology (NTNU), Trondheim 7491, Norway
| | - Markus Garst
- Institute
of Theoretical Solid State Physics, Karlsruhe
Institute of Technology, 76049 Karlsruhe, Germany
- Institute
for Quantum Materials and Technology, Karlsruhe
Institute of Technology, 76021 Karlsruhe, Germany
| | - Dennis Meier
- Department
of Materials Science and Engineering, Norwegian
University of Science and Technology (NTNU), Trondheim 7491, Norway
- Center
for Quantum Spintronics, Department of Physics,
Norwegian University of Science and Technology (NTNU), Trondheim 7491, Norway
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6
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Schoenherr P, Stepanova M, Lysne EN, Kanazawa N, Tokura Y, Bergman A, Meier D. Dislocation-Driven Relaxation Processes at the Conical to Helical Phase Transition in FeGe. ACS NANO 2021; 15:17508-17514. [PMID: 34664932 DOI: 10.1021/acsnano.1c04302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The formation of topological spin textures at the nanoscale has a significant impact on the long-range order and dynamical response of magnetic materials. We study the relaxation mechanisms at the conical-to-helical phase transition in the chiral magnet FeGe. By combining macroscopic ac susceptibility measurement, surface-sensitive magnetic force microscopy, and micromagnetic simulations, we demonstrate how the motion of magnetic topological defects, here edge dislocations, impacts the local formation of a stable helimagnetic spin structure. Although the simulations show that the edge dislocations can move with a velocity up to 100 m/s through the helimagnetic background, their dynamics are observed to disturb the magnetic order on the time scale of minutes due to randomly distributed pinning sites. The results corroborate the substantial impact of dislocation motions on the nanoscale spin structure in chiral magnets, revealing previously hidden effects on the formation of helimagnetic domains and domain walls.
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Affiliation(s)
- Peggy Schoenherr
- Department of Materials, ETH Zürich, Vladimir-Prelog-Weg 4, 8093 Zurich, Switzerland
- School of Materials Science and Engineering, UNSW Sydney, Sydney, NSW 2052, Australia
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), UNSW Sydney, Sydney, NSW 2052, Australia
| | - Mariia Stepanova
- Department of Materials Science and Engineering, Norwegian University of Science and Technology (NTNU), Sem Sælandsvei 12, 7034 Trondheim, Norway
| | - Erik Nikolai Lysne
- Department of Materials Science and Engineering, Norwegian University of Science and Technology (NTNU), Sem Sælandsvei 12, 7034 Trondheim, Norway
| | - Naoya Kanazawa
- Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan
| | - Yoshinori Tokura
- Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - Anders Bergman
- Department of Physics and Astronomy, Uppsala University, PO Box 516, Uppsala 75120, Sweden
| | - Dennis Meier
- Department of Materials Science and Engineering, Norwegian University of Science and Technology (NTNU), Sem Sælandsvei 12, 7034 Trondheim, Norway
- Center for Quantum Spintronics, NTNU, Trondheim 7034, Norway
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7
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Kúkoľová A, Dimitrievska M, Litvinchuk AP, Ramanandan SP, Tappy N, Menon H, Borg M, Grundler D, Fontcuberta I Morral A. Cubic, hexagonal and tetragonal FeGe x phases ( x = 1, 1.5, 2): Raman spectroscopy and magnetic properties. CrystEngComm 2021; 23:6506-6517. [PMID: 34602862 PMCID: PMC8474057 DOI: 10.1039/d1ce00970b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Accepted: 08/20/2021] [Indexed: 11/30/2022]
Abstract
There is currently an emerging drive towards computational materials design and fabrication of predicted novel materials. One of the keys to developing appropriate fabrication methods is determination of the composition and phase. Here we explore the FeGe system and establish reference Raman signatures for the distinction between FeGe hexagonal and cubic structures, as well as FeGe2 and Fe2Ge3 phases. The experimental results are substantiated by first principles lattice dynamics calculations as well as by complementary structural characterization such as transmission electron microscopy and X-ray diffraction, along with magnetic measurements.
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Affiliation(s)
- A Kúkoľová
- Laboratory of Semiconductor Materials, Institute of Materials, School of Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
- Laboratory of Nanoscale Magnetic Materials and Magnonics, Institute of Materials, Ecole Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
| | - M Dimitrievska
- Laboratory of Semiconductor Materials, Institute of Materials, School of Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
| | - A P Litvinchuk
- Texas Center for Superconductivity at UH, Department of Physics, University of Houston USA
| | - S P Ramanandan
- Laboratory of Semiconductor Materials, Institute of Materials, School of Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
| | - N Tappy
- Laboratory of Semiconductor Materials, Institute of Materials, School of Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
| | - H Menon
- Electrical and Information Technology, Lund University Lund Sweden
- NanoLund, Lund University Lund Sweden
| | - M Borg
- Electrical and Information Technology, Lund University Lund Sweden
- NanoLund, Lund University Lund Sweden
| | - D Grundler
- Laboratory of Nanoscale Magnetic Materials and Magnonics, Institute of Materials, Ecole Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
- Institute of Electrical and Micro Engineering, School of Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
| | - A Fontcuberta I Morral
- Laboratory of Semiconductor Materials, Institute of Materials, School of Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
- Institute of Physics, School of Basic Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
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8
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Aqeel A, Sahliger J, Taniguchi T, Mändl S, Mettus D, Berger H, Bauer A, Garst M, Pfleiderer C, Back CH. Microwave Spectroscopy of the Low-Temperature Skyrmion State in Cu_{2}OSeO_{3}. PHYSICAL REVIEW LETTERS 2021; 126:017202. [PMID: 33480751 DOI: 10.1103/physrevlett.126.017202] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 12/01/2020] [Indexed: 06/12/2023]
Abstract
In the cubic chiral magnet Cu_{2}OSeO_{3} a low-temperature skyrmion state (LTS) and a concomitant tilted conical state are observed for magnetic fields parallel to ⟨100⟩. Here, we report on the dynamic resonances of these novel magnetic states. After promoting the nucleation of the LTS by means of field cycling, we apply broadband microwave spectroscopy in two experimental geometries that provide either predominantly in-plane or out-of-plane excitation. By comparing the results to linear spin-wave theory, we clearly identify resonant modes associated with the tilted conical state, the gyrational and breathing modes associated with the LTS, as well as the hybridization of the breathing mode with a dark octupole gyration mode mediated by the magnetocrystalline anisotropies. Most intriguingly, our findings suggest that under decreasing fields the hexagonal skyrmion lattice becomes unstable with respect to an oblique deformation, reflected in the formation of elongated skyrmions.
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Affiliation(s)
- Aisha Aqeel
- Physik-Department, Technische Universität München, D-85748 Garching, Germany
| | - Jan Sahliger
- Physik-Department, Technische Universität München, D-85748 Garching, Germany
| | - Takuya Taniguchi
- Physik-Department, Technische Universität München, D-85748 Garching, Germany
| | - Stefan Mändl
- Physik-Department, Technische Universität München, D-85748 Garching, Germany
| | - Denis Mettus
- Physik-Department, Technische Universität München, D-85748 Garching, Germany
| | - Helmuth Berger
- École Polytechnique Federale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Andreas Bauer
- Physik-Department, Technische Universität München, D-85748 Garching, Germany
| | - Markus Garst
- Institut für Theoretische Festkörperphysik, Karlsruhe Institute of Technology, D-76131 Karlsruhe, Germany
- Institute for quantum materials and technology, Karlsruhe Institute of Technology, D-76344 Eggenstein-Leopoldshafen, Germany
| | | | - Christian H Back
- Physik-Department, Technische Universität München, D-85748 Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), D-80799 München, Germany
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9
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Jena J, Stinshoff R, Saha R, Srivastava AK, Ma T, Deniz H, Werner P, Felser C, Parkin SSP. Observation of Magnetic Antiskyrmions in the Low Magnetization Ferrimagnet Mn 2Rh 0.95Ir 0.05Sn. NANO LETTERS 2020; 20:59-65. [PMID: 31809059 PMCID: PMC6953472 DOI: 10.1021/acs.nanolett.9b02973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Revised: 12/04/2019] [Indexed: 06/10/2023]
Abstract
Recently, magnetic antiskyrmions were discovered in Mn1.4Pt0.9Pd0.1Sn, an inverse tetragonal Heusler compound that is nominally a ferrimagnet, but which can only be formed with substantial Mn vacancies. The vacancies reduce considerably the compensation of the moments between the two expected antiferromagnetically coupled Mn sub-lattices so that the overall magnetization is very high and the compound is almost a "ferromagnet". Here, we report the observation of antiskyrmions in a second inverse tetragonal Heusler compound, Mn2Rh0.95Ir0.05Sn, which can be formed stoichiometrically without any Mn vacancies and which thus exhibits a much smaller magnetization. Individual and lattices of antiskyrmions can be stabilized over a wide range of temperature from near room temperature to 100 K, the base temperature of the Lorentz transmission electron microscope used to image them. In low magnetic fields helical spin textures are found which evolve into antiskyrmion structures in the presence of small magnetic fields. A weaker Dzyaloshinskii-Moriya interaction (DMI), that stabilizes the antiskyrmions, is expected for the 4d element Rh as compared to the 5d element Pt, so that the observation of antiskyrmions in Mn2Rh0.95Ir0.05Sn establishes the intrinsic stability of antiskyrmions in these Heusler compounds. Moreover, the finding of antiskyrmions with substantially lower magnetization promises, via chemical tuning, even zero moment antiskyrmions with important technological import.
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Affiliation(s)
- Jagannath Jena
- Max Planck
Institute of Microstructure Physics, Weinberg 2, 06120 Halle (Saale), Germany
| | - Rolf Stinshoff
- Max
Planck Institute for Chemical Physics of Solids, Nöthnitzer Strasse 40, 01187 Dresden, Germany
| | - Rana Saha
- Max Planck
Institute of Microstructure Physics, Weinberg 2, 06120 Halle (Saale), Germany
| | - Abhay K. Srivastava
- Max Planck
Institute of Microstructure Physics, Weinberg 2, 06120 Halle (Saale), Germany
- Institute
of Physics, Martin Luther University, Halle-Wittenberg, 06120 Halle (Saale), Germany
| | - Tianping Ma
- Max Planck
Institute of Microstructure Physics, Weinberg 2, 06120 Halle (Saale), Germany
| | - Hakan Deniz
- Max Planck
Institute of Microstructure Physics, Weinberg 2, 06120 Halle (Saale), Germany
| | - Peter Werner
- Max Planck
Institute of Microstructure Physics, Weinberg 2, 06120 Halle (Saale), Germany
| | - Claudia Felser
- Max
Planck Institute for Chemical Physics of Solids, Nöthnitzer Strasse 40, 01187 Dresden, Germany
| | - Stuart S. P. Parkin
- Max Planck
Institute of Microstructure Physics, Weinberg 2, 06120 Halle (Saale), Germany
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10
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Shen LQ, Luo P, Hu YC, Bai HY, Sun YH, Sun BA, Liu YH, Wang WH. Shear-band affected zone revealed by magnetic domains in a ferromagnetic metallic glass. Nat Commun 2018; 9:4414. [PMID: 30356051 PMCID: PMC6200802 DOI: 10.1038/s41467-018-06919-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 09/27/2018] [Indexed: 11/23/2022] Open
Abstract
Plastic deformation of metallic glasses (MGs) has long been considered to be confined to nanoscale shear bands, but recently an affected zone around the shear band was found. Yet, due to technical limitations, the shear-band affected zone (SBAZ), which is critical for understanding shear banding and design of ductile MGs, has yet to be precisely identified. Here, by using magnetic domains as a probe with sufficiently high sensitivity and spatial resolution, we unveil the structure of SBAZs in detail. We demonstrate that shear banding is accompanied by a micrometer-scale SBAZ with a gradient in the strain field, and multiple shear bands interact through the superimposition of SBAZs. There also exists an ultra-long-range gradual elastic stress field extending hundreds of micrometers away from the shear band. Our findings provide a comprehensive picture on shear banding and are important for elucidating the micro-mechanisms of plastic deformation in glasses. Metallic glasses deform along nanoscale shear bands, and while it is known that they affect the neighboring glass regions, exactly how is unclear. Here, the authors use magnetic force microscopy to atomically resolve the shear-band affected zone and show its effects extends much further than previously thought.
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Affiliation(s)
- L Q Shen
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China.,University of Chinese Academy of Sciences, 100049, Beijing, China
| | - P Luo
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China.,University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Y C Hu
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China.,University of Chinese Academy of Sciences, 100049, Beijing, China
| | - H Y Bai
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China.,University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Y H Sun
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China.,University of Chinese Academy of Sciences, 100049, Beijing, China
| | - B A Sun
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China.,University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Y H Liu
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China. .,University of Chinese Academy of Sciences, 100049, Beijing, China. .,Beijing Advanced Innovation Center for Materials Genome Engineering, 100083, Beijing, China.
| | - W H Wang
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China. .,University of Chinese Academy of Sciences, 100049, Beijing, China. .,Beijing Advanced Innovation Center for Materials Genome Engineering, 100083, Beijing, China.
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11
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Karube K, White JS, Morikawa D, Dewhurst CD, Cubitt R, Kikkawa A, Yu X, Tokunaga Y, Arima TH, Rønnow HM, Tokura Y, Taguchi Y. Disordered skyrmion phase stabilized by magnetic frustration in a chiral magnet. SCIENCE ADVANCES 2018; 4:eaar7043. [PMID: 30225364 PMCID: PMC6140611 DOI: 10.1126/sciadv.aar7043] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 08/03/2018] [Indexed: 05/23/2023]
Abstract
Magnetic skyrmions are vortex-like topological spin textures often observed to form a triangular-lattice skyrmion crystal in structurally chiral magnets with the Dzyaloshinskii-Moriya interaction. Recently, β-Mn structure-type Co-Zn-Mn alloys were identified as a new class of chiral magnet to host such skyrmion crystal phases, while β-Mn itself is known as hosting an elemental geometrically frustrated spin liquid. We report the intermediate composition system Co7Zn7Mn6 to be a unique host of two disconnected, thermal-equilibrium topological skyrmion phases; one is a conventional skyrmion crystal phase stabilized by thermal fluctuations and restricted to exist just below the magnetic transition temperature Tc, and the other is a novel three-dimensionally disordered skyrmion phase that is stable well below Tc. The stability of this new disordered skyrmion phase is due to a cooperative interplay between the chiral magnetism with the Dzyaloshinskii-Moriya interaction and the frustrated magnetism inherent to β-Mn.
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Affiliation(s)
- Kosuke Karube
- RIKEN Center for Emergent Matter Science, Wako 351-0198, Japan
| | - Jonathan S. White
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, CH-5232 Villigen, Switzerland
| | | | - Charles D. Dewhurst
- Institut Laue-Langevin, 71 Avenue des Martyrs, CS 20156, 38042 Grenoble Cedex 9, France
| | - Robert Cubitt
- Institut Laue-Langevin, 71 Avenue des Martyrs, CS 20156, 38042 Grenoble Cedex 9, France
| | - Akiko Kikkawa
- RIKEN Center for Emergent Matter Science, Wako 351-0198, Japan
| | - Xiuzhen Yu
- RIKEN Center for Emergent Matter Science, Wako 351-0198, Japan
| | - Yusuke Tokunaga
- Department of Advanced Materials Science, University of Tokyo, Kashiwa 277-8561, Japan
| | - Taka-hisa Arima
- RIKEN Center for Emergent Matter Science, Wako 351-0198, Japan
- Department of Advanced Materials Science, University of Tokyo, Kashiwa 277-8561, Japan
| | - Henrik M. Rønnow
- Laboratory for Quantum Magnetism, Institute of Physics, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Yoshinori Tokura
- RIKEN Center for Emergent Matter Science, Wako 351-0198, Japan
- Department of Applied Physics, University of Tokyo, Bunkyo-ku 113-8656, Japan
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12
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Fin S, Silvani R, Tacchi S, Marangolo M, Garnier LC, Eddrief M, Hepburn C, Fortuna F, Rettori A, Pini MG, Bisero D. Straight motion of half-integer topological defects in thin Fe-N magnetic films with stripe domains. Sci Rep 2018; 8:9339. [PMID: 29921938 PMCID: PMC6008308 DOI: 10.1038/s41598-018-27283-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 05/31/2018] [Indexed: 11/09/2022] Open
Abstract
In thin magnetic films with perpendicular magnetic anisotropy, a periodic “up-down” stripe-domain structure can be originated at remanence, on a mesoscopic scale (~100 nm) comparable with film thickness, by the competition between short-range exchange coupling and long-range dipolar interaction. However, translational order is perturbed because magnetic edge dislocations are spontaneously nucleated. Such topological defects play an important role in magnetic films since they promote the in-plane magnetization reversal of stripes and, in superconductor/ferromagnet hybrids, the creation of superconducting vortex clusters. Combining magnetic force microscopy experiments and micromagnetic simulations, we investigated the motion of two classes of magnetic edge dislocations, randomly distributed in an \documentclass[12pt]{minimal}
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\begin{document}$${{\rm{N}}}_{2}^{+}$$\end{document}N2+-implanted Fe film. They were found to move in opposite directions along straight trajectories parallel to the stripes axis, when driven by a moderate dc magnetic field. Using the approximate Thiele equation, analytical expressions for the forces acting on such magnetic defects and a microscopic explanation for the direction of their motion could be obtained. Straight trajectories are related to the presence of a periodic stripe domain pattern, which imposes the gyrotropic force to vanish even if a nonzero, half-integer topological charge is carried by the defects in some layers across the film thickness.
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Affiliation(s)
- S Fin
- Dipartimento di Fisica e Scienze della Terra, Università degli Studi di Ferrara, Via Saragat 1, I-44122, Ferrara, Italy
| | - R Silvani
- Dipartimento di Fisica e Geologia, Università degli Studi di Perugia, Via Pascoli, I-06123, Perugia, Italy
| | - S Tacchi
- Istituto Officina dei Materiali del CNR (CNR-IOM), Sede Secondaria di Perugia, c/o Dipartimento di Fisica e Geologia, Università degli Studi di Perugia, I-06123, Perugia, Italy
| | - M Marangolo
- Sorbonne Université, CNRS, Institut des NanoSciences de Paris, UMR 7588, F-75252, Paris, France
| | - L-C Garnier
- Sorbonne Université, CNRS, Institut des NanoSciences de Paris, UMR 7588, F-75252, Paris, France.,Université Versailles St-Quentin, LISV, Bâtiment Boucher, Pôle scientifique et technologique de Vélizy, 10-12 avenue de l'Europe, F-78140, Vélizy, France
| | - M Eddrief
- Sorbonne Université, CNRS, Institut des NanoSciences de Paris, UMR 7588, F-75252, Paris, France
| | - C Hepburn
- Sorbonne Université, CNRS, Institut des NanoSciences de Paris, UMR 7588, F-75252, Paris, France
| | - F Fortuna
- CSNSM, Université Paris-Sud and CNRS/IN2P3, Université Paris-Saclay, F-91405, Orsay, France
| | - A Rettori
- Dipartimento di Fisica ed Astronomia, Università degli Studi di Firenze, Via Sansone 1, I-50019, Sesto Fiorentino, FI, Italy
| | - M G Pini
- Istituto dei Sistemi Complessi del CNR (CNR-ISC), Sede Secondaria di Sesto Fiorentino, Via Madonna del Piano 10, I-50019, Sesto Fiorentino, FI, Italy.
| | - D Bisero
- Dipartimento di Fisica e Scienze della Terra, Università degli Studi di Ferrara, Via Saragat 1, I-44122, Ferrara, Italy. .,CNISM, Unità di Ferrara, I-44122, Ferrara, Italy.
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13
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Schoenherr P, Giraldo LM, Lilienblum M, Trassin M, Meier D, Fiebig M. Magnetoelectric Force Microscopy on Antiferromagnetic 180 ∘ Domains in Cr₂O₃. MATERIALS 2017; 10:ma10091051. [PMID: 28880233 PMCID: PMC5615706 DOI: 10.3390/ma10091051] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 08/18/2017] [Accepted: 08/23/2017] [Indexed: 11/16/2022]
Abstract
Magnetoelectric force microscopy (MeFM) is characterized as methodical tool for the investigation of antiferromagnetic domain states, in particular of the 180∘ variety. As reference compound for this investigation we use Cr2O3. Access to the antiferromagnetic order is provided by the linear magnetoelectric effect. We resolve the opposite antiferromagnetic 180∘ domain states of Cr2O3 and estimate the sensitivity of the MeFM approach, its inherent advantages in comparison to alternative techniques and its general feasibility for probing antiferromagnetic order.
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Affiliation(s)
- Peggy Schoenherr
- Department of Materials, ETH Zurich, Vladimir-Prelog-Weg 4, 8093 Zürich, Switzerland.
| | - L Marcela Giraldo
- Department of Materials, ETH Zurich, Vladimir-Prelog-Weg 4, 8093 Zürich, Switzerland.
| | - Martin Lilienblum
- Department of Materials, ETH Zurich, Vladimir-Prelog-Weg 4, 8093 Zürich, Switzerland.
| | - Morgan Trassin
- Department of Materials, ETH Zurich, Vladimir-Prelog-Weg 4, 8093 Zürich, Switzerland.
| | - Dennis Meier
- Department of Materials Science and Engineering, Norwegian University of Science and Technology, Sem Sælandsvei 12, 7034 Trondheim, Norway.
| | - Manfred Fiebig
- Department of Materials, ETH Zurich, Vladimir-Prelog-Weg 4, 8093 Zürich, Switzerland.
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14
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Abstract
Chiral magnets are promising materials for the realisation of high-density and low-power spintronic memory devices. For these future applications, a key requirement is the synthesis of appropriate materials in the form of thin films ordering well above room temperature. Driven by the Dzyaloshinskii-Moriya interaction, the cubic compound FeGe exhibits helimagnetism with a relatively high transition temperature of 278 K in bulk crystals. We demonstrate that this temperature can be enhanced significantly in thin films. Using x-ray scattering and ferromagnetic resonance techniques, we provide unambiguous experimental evidence for long-wavelength helimagnetic order at room temperature and magnetic properties similar to the bulk material. We obtain αintr = 0.0036 ± 0.0003 at 310 K for the intrinsic damping parameter. We probe the dynamics of the system by means of muon-spin rotation, indicating that the ground state is reached via a freezing out of slow dynamics. Our work paves the way towards the fabrication of thin films of chiral magnets that host certain spin whirls, so-called skyrmions, at room temperature and potentially offer integrability into modern electronics.
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15
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Shamsudhin N, Tao Y, Sort J, Jang B, Degen CL, Nelson BJ, Pané S. Magnetometry of Individual Polycrystalline Ferromagnetic Nanowires. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2016; 12:6363-6369. [PMID: 27690370 DOI: 10.1002/smll.201602338] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 08/25/2016] [Indexed: 06/06/2023]
Abstract
Ferromagnetic nanowires are finding use as untethered sensors and actuators for probing micro- and nanoscale biophysical phenomena, such as for localized sensing and application of forces and torques on biological samples, for tissue heating through magnetic hyperthermia, and for microrheology. Quantifying the magnetic properties of individual isolated nanowires is crucial for such applications. Dynamic cantilever magnetometry is used to measure the magnetic properties of individual sub-500 nm diameter polycrystalline nanowires of Ni and Ni80 Co20 fabricated by template-assisted electrochemical deposition. The values are compared with bulk, ensemble measurements when the nanowires are still embedded within their growth matrix. It is found that single-particle and ensemble measurements of nanowires yield significantly different results that reflect inter-nanowire interactions and chemical modifications of the sample during the release process from the growth matrix. The results highlight the importance of performing single-particle characterization for objects that will be used as individual magnetic nanoactuators or nanosensors in biomedical applications.
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Affiliation(s)
- Naveen Shamsudhin
- Multi-Scale Robotics Laboratory, ETH Zurich, Zurich, 8092, Switzerland
| | - Ye Tao
- Department of Physics, ETH Zurich, Zurich, 8092, Switzerland
| | - Jordi Sort
- Institució Catalana de Recerca i Estudis Avançats (ICREA) and Departament de Física, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, 08193, Spain
| | - Bumjin Jang
- Multi-Scale Robotics Laboratory, ETH Zurich, Zurich, 8092, Switzerland
| | | | - Bradley J Nelson
- Multi-Scale Robotics Laboratory, ETH Zurich, Zurich, 8092, Switzerland
| | - Salvador Pané
- Multi-Scale Robotics Laboratory, ETH Zurich, Zurich, 8092, Switzerland
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