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Yuan LD, Zhang X, Acosta CM, Zunger A. Uncovering spin-orbit coupling-independent hidden spin polarization of energy bands in antiferromagnets. Nat Commun 2023; 14:5301. [PMID: 37652909 PMCID: PMC10471643 DOI: 10.1038/s41467-023-40877-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 08/15/2023] [Indexed: 09/02/2023] Open
Abstract
Many textbook physical effects in crystals are enabled by some specific symmetries. In contrast to such 'apparent effects', 'hidden effect X' refers to the general condition where the nominal global system symmetry would disallow the effect X, whereas the symmetry of local sectors within the crystal would enable effect X. Known examples include the hidden Rashba and/or hidden Dresselhaus spin polarization that require spin-orbit coupling, but unlike their apparent counterparts are demonstrated to exist in non-magnetic systems even in inversion-symmetric crystals. Here, we discuss hidden spin polarization effect in collinear antiferromagnets without the requirement for spin-orbit coupling (SOC). Symmetry analysis suggests that antiferromagnets hosting such effect can be classified into six types depending on the global vs local symmetry. We identify which of the possible collinear antiferromagnetic compounds will harbor such hidden polarization and validate these symmetry enabling predictions with first-principles density functional calculations for several representative compounds. This will boost the theoretical and experimental efforts in finding new spin-polarized materials.
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Affiliation(s)
- Lin-Ding Yuan
- Renewable and Sustainable Energy Institute, University of Colorado, Boulder, CO, 80309, USA
| | - Xiuwen Zhang
- Renewable and Sustainable Energy Institute, University of Colorado, Boulder, CO, 80309, USA
| | - Carlos Mera Acosta
- Center for Natural and Human Sciences, Federal University of ABC, Santo Andre, São Paulo, Brazil
| | - Alex Zunger
- Renewable and Sustainable Energy Institute, University of Colorado, Boulder, CO, 80309, USA.
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2
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Hirst J, Ruta S, Jackson J, Ostler T. Simulations of magnetization reversal in FM/AFM bilayers with THz frequency pulses. Sci Rep 2023; 13:12270. [PMID: 37507443 PMCID: PMC10382508 DOI: 10.1038/s41598-023-39175-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 07/20/2023] [Indexed: 07/30/2023] Open
Abstract
It is widely known that antiferromagnets (AFMs) display a high frequency response in the terahertz (THz) range, which opens up the possibility for ultrafast control of their magnetization for next generation data storage and processing applications. However, because the magnetization of the different sublattices cancel, their state is notoriously difficult to read. One way to overcome this is to couple AFMs to ferromagnets-whose state is trivially read via magneto-resistance sensors. Here we present conditions, using theoretical modelling, that it is possible to switch the magnetization of an AFM/FM bilayer using THz frequency pulses with moderate field amplitude and short durations, achievable in experiments. Consistent switching is observed in the phase diagrams for an order of magnitude increase in the interface coupling and a tripling in the thickness of the FM layer. We demonstrate a range of reversal paths that arise due to the combination of precession in the materials and the THz-induced fields. Our analysis demonstrates that the AFM drives the switching and results in a much higher frequency dynamics in the FM due to the exchange coupling at the interface. The switching is shown to be robust over a broad range of temperatures relevant for device applications.
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Affiliation(s)
- Joel Hirst
- Materials & Engineering Research Institute, Sheffield Hallam University, Howard Street, Sheffield, S1 1WB, UK.
| | - Sergiu Ruta
- Materials & Engineering Research Institute, Sheffield Hallam University, Howard Street, Sheffield, S1 1WB, UK
- The Department of Engineering and Mathematics, Sheffield Hallam University, Howard Street, Sheffield, S1 1WB, UK
| | - Jerome Jackson
- Scientific Computing Department, STFC Daresbury Laboratory, Warrington, WA4 4AD, UK
| | - Thomas Ostler
- Department of Physics & Mathematics, University of Hull, Hull, HU6 7RX, UK
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3
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Makushko P, Kosub T, Pylypovskyi OV, Hedrich N, Li J, Pashkin A, Avdoshenko S, Hübner R, Ganss F, Wolf D, Lubk A, Liedke MO, Butterling M, Wagner A, Wagner K, Shields BJ, Lehmann P, Veremchuk I, Fassbender J, Maletinsky P, Makarov D. Flexomagnetism and vertically graded Néel temperature of antiferromagnetic Cr2O3 thin films. Nat Commun 2022; 13:6745. [DOI: 10.1038/s41467-022-34233-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 10/13/2022] [Indexed: 11/09/2022] Open
Abstract
AbstractAntiferromagnetic insulators are a prospective materials platform for magnonics, spin superfluidity, THz spintronics, and non-volatile data storage. A magnetomechanical coupling in antiferromagnets offers vast advantages in the control and manipulation of the primary order parameter yet remains largely unexplored. Here, we discover a new member in the family of flexoeffects in thin films of Cr2O3. We demonstrate that a gradient of mechanical strain can impact the magnetic phase transition resulting in the distribution of the Néel temperature along the thickness of a 50-nm-thick film. The inhomogeneous reduction of the antiferromagnetic order parameter induces a flexomagnetic coefficient of about 15 μB nm−2. The antiferromagnetic ordering in the inhomogeneously strained films can persist up to 100 °C, rendering Cr2O3 relevant for industrial electronics applications. Strain gradient in Cr2O3 thin films enables fundamental research on magnetomechanics and thermodynamics of antiferromagnetic solitons, spin waves and artificial spin ice systems in magnetic materials with continuously graded parameters.
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4
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Defect-driven antiferromagnetic domain walls in CuMnAs films. Nat Commun 2022; 13:724. [PMID: 35132068 PMCID: PMC8821625 DOI: 10.1038/s41467-022-28311-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 01/19/2022] [Indexed: 11/10/2022] Open
Abstract
Efficient manipulation of antiferromagnetic (AF) domains and domain walls has opened up new avenues of research towards ultrafast, high-density spintronic devices. AF domain structures are known to be sensitive to magnetoelastic effects, but the microscopic interplay of crystalline defects, strain and magnetic ordering remains largely unknown. Here, we reveal, using photoemission electron microscopy combined with scanning X-ray diffraction imaging and micromagnetic simulations, that the AF domain structure in CuMnAs thin films is dominated by nanoscale structural twin defects. We demonstrate that microtwin defects, which develop across the entire thickness of the film and terminate on the surface as characteristic lines, determine the location and orientation of 180∘ and 90∘ domain walls. The results emphasize the crucial role of nanoscale crystalline defects in determining the AF domains and domain walls, and provide a route to optimizing device performance. Antiferromagnets offer the potential for higher speed and density than ferromagnetic materials for spintronic devices. Here, Reimers et al study the domain structure of CuMnAs, demonstrating the role of defects in stabilizing the location and orientation of antiferromagnetic domain walls.
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5
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Salemi L, Berritta M, Nandy AK, Oppeneer PM. Orbitally dominated Rashba-Edelstein effect in noncentrosymmetric antiferromagnets. Nat Commun 2019; 10:5381. [PMID: 31772174 PMCID: PMC6879646 DOI: 10.1038/s41467-019-13367-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2019] [Accepted: 11/05/2019] [Indexed: 11/09/2022] Open
Abstract
Efficient manipulation of magnetic order with electric current pulses is desirable for achieving fast spintronic devices. The Rashba-Edelstein effect, wherein spin polarization is electrically induced in noncentrosymmetric systems, provides a mean to achieve staggered spin-orbit torques. Initially predicted for spin, its orbital counterpart has been disregarded up to now. Here we report a generalized Rashba-Edelstein effect, which generates not only spin polarization but also orbital polarization, which we find to be far from being negligible. We show that the orbital Rashba-Edelstein effect does not require spin-orbit coupling to exist. We present first-principles calculations of the frequency-dependent spin and orbital Rashba-Edelstein tensors for the noncentrosymmetric antiferromagnets CuMnAs and Mn[Formula: see text]Au. We show that the electrically induced local magnetization can exhibit Rashba-like or Dresselhaus-like symmetries, depending on the magnetic configuration. We compute sizable induced magnetizations at optical frequencies, which suggest that electric-field driven switching could be achieved at much higher frequencies.
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Affiliation(s)
- Leandro Salemi
- Department of Physics and Astronomy, Uppsala University, P. O. Box 516, S-751 20, Uppsala, Sweden.
| | - Marco Berritta
- Department of Physics and Astronomy, Uppsala University, P. O. Box 516, S-751 20, Uppsala, Sweden
| | - Ashis K Nandy
- Department of Physics and Astronomy, Uppsala University, P. O. Box 516, S-751 20, Uppsala, Sweden.,School of Physical Sciences, National Institute of Science Education and Research, HBNI, Jatni, 752050, Odisha, India
| | - Peter M Oppeneer
- Department of Physics and Astronomy, Uppsala University, P. O. Box 516, S-751 20, Uppsala, Sweden.
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6
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Xiao W, Yang Y, Chi X, Liu B, Du Y, Yang P, Herng TS, Gao D, Song W, Feng YP, Rusydi A, Ding J. High-Magnetization Tetragonal Ferrite-Based Films Induced by Carbon and Oxygen Vacancy Pairs. ACS APPLIED MATERIALS & INTERFACES 2019; 11:1049-1056. [PMID: 30560652 DOI: 10.1021/acsami.8b17902] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Herein, a low-temperature thermal decomposition method is utilized to grow new stable tetragonal Fe3O4-based thick ferrite films. The tetragonal Fe3O4-based film possesses high saturation magnetization of ∼800 emu/cm3. Doping with approximately 10% Co results in a high-energy product of ∼10.9 MGOe with perpendicular magnetocrystalline anisotropy, whereas doping with Ni increases electrical resistivity by a factor of 6 and retains excellent soft magnetic properties (high saturation magnetization and low coercivity). A combined experimental and first-principles study reveals that carbon interstitials (CiB) and oxygen vacancies (VO) form CiB-VO pairs which stabilize the tetragonal phase and enhance saturation magnetization. The magnetization enhancement is further attributed to local ferromagnetic coupling between FeA and FeB induced by CiB-VO pairs in a tetragonal spinel ferrite lattice.
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Affiliation(s)
- Wen Xiao
- Department of Materials Science and Engineering , National University of Singapore , 9 Engineering Drive 1 , Singapore 117575 , Singapore
| | - Yang Yang
- College of Electronic Science and Technology , Shenzhen University , Shenzhen 518060 , P. R. China
| | - Xiao Chi
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542 , Singapore
- Singapore Synchrotron Light Source , National University of Singapore , 5 Research Link , Singapore 117603 , Singapore
| | - Binghai Liu
- Department of Product, Test and Failure Analysis , GLOBALFOUNDRIES, Singapore Pte. Ltd. , Singapore 738406 , Singapore
| | - Yonghua Du
- Institute of Chemical and Engineering Sciences, A*STAR , 1 Pesek Road , Jurong Island, Singapore 627833 , Singapore
| | - Ping Yang
- Singapore Synchrotron Light Source , National University of Singapore , 5 Research Link , Singapore 117603 , Singapore
| | - Tun Seng Herng
- Department of Materials Science and Engineering , National University of Singapore , 9 Engineering Drive 1 , Singapore 117575 , Singapore
| | - Daqiang Gao
- Key Laboratory for Magnetism and Magnetic Materials of MOE, Key Laboratory of Special Function Materials and Structure Design of MOE , Lanzhou University , Lanzhou 730000 , P. R. China
| | - Wendong Song
- Data Storage Institute, Agency for Science, Technology and Research (A*STAR) , 2 Fusionopolis Way, #08-01 Innovis , Singapore 138634 , Singapore
| | - Yuan Ping Feng
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542 , Singapore
| | - Andrivo Rusydi
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542 , Singapore
- Singapore Synchrotron Light Source , National University of Singapore , 5 Research Link , Singapore 117603 , Singapore
| | - Jun Ding
- Department of Materials Science and Engineering , National University of Singapore , 9 Engineering Drive 1 , Singapore 117575 , Singapore
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7
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Wadley P, Edmonds KW, Shahedkhah MR, Campion RP, Gallagher BL, Železný J, Kuneš J, Novák V, Jungwirth T, Saidl V, Němec P, Maccherozzi F, Dhesi SS. Control of antiferromagnetic spin axis orientation in bilayer Fe/CuMnAs films. Sci Rep 2017; 7:11147. [PMID: 28894219 PMCID: PMC5593844 DOI: 10.1038/s41598-017-11653-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 08/25/2017] [Indexed: 11/22/2022] Open
Abstract
Using x-ray magnetic circular and linear dichroism techniques, we demonstrate a collinear exchange coupling between an epitaxial antiferromagnet, tetragonal CuMnAs, and an Fe surface layer. A small uncompensated Mn magnetic moment is observed which is antiparallel to the Fe magnetization. The staggered magnetization of the 5 nm thick CuMnAs layer is rotatable under small magnetic fields, due to the interlayer exchange coupling. This allows us to obtain the x-ray magnetic linear dichroism spectra for different crystalline orientations of CuMnAs in the (001) plane. This is a key parameter for enabling the understanding of domain structures in CuMnAs imaged using x-ray magnetic linear dichroism microscopy techniques.
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Affiliation(s)
- P Wadley
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, United Kingdom.
| | - K W Edmonds
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, United Kingdom
| | - M R Shahedkhah
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, United Kingdom
| | - R P Campion
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, United Kingdom
| | - B L Gallagher
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, United Kingdom
| | - J Železný
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, 162 00, Praha 6, Czech Republic.,Max Planck Institute for Chemical Physics of Solids, 01187, Dresden, Germany
| | - J Kuneš
- Institute of Physics, Czech Academy of Sciences, Na Slovance 1999/2, 182 21, Praha 8, Czech Republic.,Institute of Solid State Physics, TU Wien, Wiedner Hauptstr. 8, 1040, Wien, Austria
| | - V Novák
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, 162 00, Praha 6, Czech Republic
| | - T Jungwirth
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, United Kingdom.,Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, 162 00, Praha 6, Czech Republic
| | - V Saidl
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, 162 00, Praha 6, Czech Republic.,Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, 121 16, Praha 2, Czech Republic
| | - P Němec
- Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, 121 16, Praha 2, Czech Republic
| | - F Maccherozzi
- Diamond Light Source, Chilton, Didcot, Oxfordshire, OX11 0DE, United Kingdom
| | - S S Dhesi
- Diamond Light Source, Chilton, Didcot, Oxfordshire, OX11 0DE, United Kingdom
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8
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Antiferromagnetic CuMnAs multi-level memory cell with microelectronic compatibility. Nat Commun 2017; 8:15434. [PMID: 28524862 PMCID: PMC5454531 DOI: 10.1038/ncomms15434] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 03/28/2017] [Indexed: 12/02/2022] Open
Abstract
Antiferromagnets offer a unique combination of properties including the radiation and magnetic field hardness, the absence of stray magnetic fields, and the spin-dynamics frequency scale in terahertz. Recent experiments have demonstrated that relativistic spin-orbit torques can provide the means for an efficient electric control of antiferromagnetic moments. Here we show that elementary-shape memory cells fabricated from a single-layer antiferromagnet CuMnAs deposited on a III–V or Si substrate have deterministic multi-level switching characteristics. They allow for counting and recording thousands of input pulses and responding to pulses of lengths downscaled to hundreds of picoseconds. To demonstrate the compatibility with common microelectronic circuitry, we implemented the antiferromagnetic bit cell in a standard printed circuit board managed and powered at ambient conditions by a computer via a USB interface. Our results open a path towards specialized embedded memory-logic applications and ultra-fast components based on antiferromagnets. Devices based on antiferromagnetic materials have advantages of robustness to external magnetic fields and the potential for ultrafast operation. Here the authors present a multilevel antiferromagnetic memory cell that can be operated using standard electronic interfaces.
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9
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Šmejkal L, Železný J, Sinova J, Jungwirth T. Electric Control of Dirac Quasiparticles by Spin-Orbit Torque in an Antiferromagnet. PHYSICAL REVIEW LETTERS 2017; 118:106402. [PMID: 28339249 DOI: 10.1103/physrevlett.118.106402] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Indexed: 06/06/2023]
Abstract
Spin orbitronics and Dirac quasiparticles are two fields of condensed matter physics initiated independently about a decade ago. Here we predict that Dirac quasiparticles can be controlled by the spin-orbit torque reorientation of the Néel vector in an antiferromagnet. Using CuMnAs as an example, we formulate symmetry criteria allowing for the coexistence of topological Dirac quasiparticles and Néel spin-orbit torques. We identify the nonsymmorphic crystal symmetry protection of Dirac band crossings whose on and off switching is mediated by the Néel vector reorientation. We predict that this concept verified by minimal model and density functional calculations in the CuMnAs semimetal antiferromagnet can lead to a topological metal-insulator transition driven by the Néel vector and to the topological anisotropic magnetoresistance.
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Affiliation(s)
- L Šmejkal
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, 162 53 Praha 6, Czech Republic
- Institut für Physik, Johannes Gutenberg Universität Mainz, D-55099 Mainz, Germany
- Faculty of Mathematics and Physics, Charles University in Prague, Ke Karlovu 3, 121 16 Prague 2, Czech Republic
| | - J Železný
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, 162 53 Praha 6, Czech Republic
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Strasse 40, D-01187 Dresden, Germany
| | - J Sinova
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, 162 53 Praha 6, Czech Republic
- Institut für Physik, Johannes Gutenberg Universität Mainz, D-55099 Mainz, Germany
| | - T Jungwirth
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, 162 53 Praha 6, Czech Republic
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom
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10
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Grzybowski MJ, Wadley P, Edmonds KW, Beardsley R, Hills V, Campion RP, Gallagher BL, Chauhan JS, Novak V, Jungwirth T, Maccherozzi F, Dhesi SS. Imaging Current-Induced Switching of Antiferromagnetic Domains in CuMnAs. PHYSICAL REVIEW LETTERS 2017; 118:057701. [PMID: 28211721 DOI: 10.1103/physrevlett.118.057701] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Indexed: 05/22/2023]
Abstract
The magnetic order in antiferromagnetic materials is hard to control with external magnetic fields. Using x-ray magnetic linear dichroism microscopy, we show that staggered effective fields generated by electrical current can induce modification of the antiferromagnetic domain structure in microdevices fabricated from a tetragonal CuMnAs thin film. A clear correlation between the average domain orientation and the anisotropy of the electrical resistance is demonstrated, with both showing reproducible switching in response to orthogonally applied current pulses. However, the behavior is inhomogeneous at the submicron level, highlighting the complex nature of the switching process in multidomain antiferromagnetic films.
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Affiliation(s)
- M J Grzybowski
- School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
- Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, PL-02668 Warsaw, Poland
| | - P Wadley
- School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - K W Edmonds
- School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - R Beardsley
- School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - V Hills
- School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - R P Campion
- School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - B L Gallagher
- School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - J S Chauhan
- School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - V Novak
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnicka 10, 162 00 Praha 6, Czech Republic
| | - T Jungwirth
- School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnicka 10, 162 00 Praha 6, Czech Republic
| | - F Maccherozzi
- Diamond Light Source, Chilton, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - S S Dhesi
- Diamond Light Source, Chilton, Didcot, Oxfordshire OX11 0DE, United Kingdom
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11
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Gomonay O, Jungwirth T, Sinova J. High Antiferromagnetic Domain Wall Velocity Induced by Néel Spin-Orbit Torques. PHYSICAL REVIEW LETTERS 2016; 117:017202. [PMID: 27419586 DOI: 10.1103/physrevlett.117.017202] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Indexed: 06/06/2023]
Abstract
We demonstrate the possibility to drive an antiferromagnetic domain wall at high velocities by fieldlike Néel spin-orbit torques. Such torques arise from current-induced local fields that alternate their orientation on each sublattice of the antiferromagnet and whose orientation depends primarily on the current direction, giving them their fieldlike character. The domain wall velocities that can be achieved by this mechanism are 2 orders of magnitude greater than the ones in ferromagnets. This arises from the efficiency of the staggered spin-orbit fields to couple to the order parameter and from the exchange-enhanced phenomena in antiferromagnetic texture dynamics, which leads to a low domain wall effective mass and the absence of a Walker breakdown limit. In addition, because of its nature, the staggered spin-orbit field can lift the degeneracy between two 180° rotated states in a collinear antiferromagnet, and it provides a force that can move such walls and control the switching of the states.
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Affiliation(s)
- O Gomonay
- Institut für Physik, Johannes Gutenberg Universität Mainz, D-55099 Mainz, Germany
- National Technical University of Ukraine "KPI", 03056 Kyiv, Ukraine
| | - T Jungwirth
- Institute of Physics Academy of Sciences of the Czech Republic, Cukrovarnicka 10, 162 00 Praha 6, Czech Republic
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - J Sinova
- Institut für Physik, Johannes Gutenberg Universität Mainz, D-55099 Mainz, Germany
- Institute of Physics Academy of Sciences of the Czech Republic, Cukrovarnicka 10, 162 00 Praha 6, Czech Republic
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