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Pan XF, Li PB, Hei XL, Zhang X, Mochizuki M, Li FL, Nori F. Magnon-Skyrmion Hybrid Quantum Systems: Tailoring Interactions via Magnons. PHYSICAL REVIEW LETTERS 2024; 132:193601. [PMID: 38804949 DOI: 10.1103/physrevlett.132.193601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 01/08/2024] [Accepted: 04/08/2024] [Indexed: 05/29/2024]
Abstract
Coherent and dissipative interactions between different quantum systems are essential for the construction of hybrid quantum systems and the investigation of novel quantum phenomena. Here, we propose and analyze a magnon-skyrmion hybrid quantum system, consisting of a micromagnet and nearby magnetic skyrmions. We predict a strong-coupling mechanism between the magnonic mode of the micromagnet and the quantized helicity degree of freedom of the skyrmion. We show that with this hybrid setup it is possible to induce magnon-mediated nonreciprocal interactions and responses between distant skyrmion qubits or between skyrmion qubits and other quantum systems like superconducting qubits. This work provides a quantum platform for the investigation of diverse quantum effects and quantum information processing with magnetic microstructures.
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Affiliation(s)
- Xue-Feng Pan
- Ministry of Education Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Shaanxi Province Key Laboratory of Quantum Information and Quantum Optoelectronic Devices, School of Physics, Xi'an Jiaotong University, Xi'an 710049, China
| | - Peng-Bo Li
- Ministry of Education Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Shaanxi Province Key Laboratory of Quantum Information and Quantum Optoelectronic Devices, School of Physics, Xi'an Jiaotong University, Xi'an 710049, China
| | - Xin-Lei Hei
- Ministry of Education Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Shaanxi Province Key Laboratory of Quantum Information and Quantum Optoelectronic Devices, School of Physics, Xi'an Jiaotong University, Xi'an 710049, China
| | - Xichao Zhang
- Department of Applied Physics, Waseda University, Okubo, Shinjuku-ku, Tokyo 169-8555, Japan
| | - Masahito Mochizuki
- Department of Applied Physics, Waseda University, Okubo, Shinjuku-ku, Tokyo 169-8555, Japan
| | - Fu-Li Li
- Ministry of Education Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Shaanxi Province Key Laboratory of Quantum Information and Quantum Optoelectronic Devices, School of Physics, Xi'an Jiaotong University, Xi'an 710049, China
| | - Franco Nori
- Theoretical Quantum Physics Laboratory, Cluster for Pioneering Research, RIKEN, Wakoshi, Saitama 351-0198, Japan
- Center for Quantum Computing, RIKEN, Wakoshi, Saitama 351-0198, Japan
- Physics Department, The University of Michigan, Ann Arbor, Michigan 48109-1040, USA
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2
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Liu C, Wang J, He W, Zhang C, Zhang S, Yuan S, Hou Z, Qin M, Xu Y, Gao X, Peng Y, Liu K, Qiu ZQ, Liu JM, Zhang X. Strain-Induced Reversible Motion of Skyrmions at Room Temperature. ACS NANO 2024; 18:761-769. [PMID: 38127497 DOI: 10.1021/acsnano.3c09090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
Magnetic skyrmions are topologically protected swirling spin textures with great potential for future spintronic applications. The ability to induce skyrmion motion using mechanical strain not only stimulates the exploration of exotic physics but also affords the opportunity to develop energy-efficient spintronic devices. However, the experimental realization of strain-driven skyrmion motion remains a formidable challenge. Herein, we demonstrate that the inhomogeneous uniaxial compressive strain can induce the movement of isolated skyrmions from regions of high strain to regions of low strain at room temperature, which was directly observed using an in situ Lorentz transmission electron microscope with a specially designed nanoindentation holder. We discover that the uniaxial compressive strain can transform skyrmions into a single domain with in-plane magnetization, resulting in the coexistence of skyrmions with a single domain along the direction of the strain gradient. Through comprehensive micromagnetic simulations, we reveal that the repulsive interactions between skyrmions and the single domain serve as the driving force behind the skyrmion motion. The precise control of skyrmion motion through strain provides exciting opportunities for designing advanced spintronic devices that leverage the intricate interplay between strain and magnetism.
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Affiliation(s)
- Chen Liu
- Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
- Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou University, Lanzhou 730000, P. R. China
| | - Junlin Wang
- School of Integrated Circuits, Guangdong University of Technology, Guangzhou 510006, China
- School of Physics, Engineering and Technology, University of York, York YO10 5DD, U.K
| | - Wa He
- Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou University, Lanzhou 730000, P. R. China
| | - Chenhui Zhang
- Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
| | - Senfu Zhang
- Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
- Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou University, Lanzhou 730000, P. R. China
| | - Shuai Yuan
- School of Mechanical and Electrical Engineering, Guilin University of Electronic Technology, Guilin 541004, P. R. China
| | - Zhipeng Hou
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute for Advanced Materials, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, P. R. China
| | - Minghui Qin
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute for Advanced Materials, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, P. R. China
| | - Yongbing Xu
- School of Integrated Circuits, Guangdong University of Technology, Guangzhou 510006, China
- School of Physics, Engineering and Technology, University of York, York YO10 5DD, U.K
| | - Xingsen Gao
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute for Advanced Materials, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, P. R. China
| | - Yong Peng
- Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou University, Lanzhou 730000, P. R. China
| | - Kai Liu
- Physics Department, Georgetown University, Washington, D.C. 20057, United States
| | - Zi Qiang Qiu
- Department of Physics, University of California at Berkeley, Berkeley, California 94720, United States
| | - Jun-Ming Liu
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute for Advanced Materials, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, P. R. China
- Laboratory of Solid State Microstructures and Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 211102, P. R. China
| | - Xixiang Zhang
- Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
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3
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Gerasimchuk VS, Gorobets YI, Gorobets OY, Gerasimchuk IV. Spatial antiferromagnetic spin texture as a nano-oscillator. Sci Rep 2023; 13:6613. [PMID: 37095166 PMCID: PMC10126036 DOI: 10.1038/s41598-023-33220-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2022] [Accepted: 04/10/2023] [Indexed: 04/26/2023] Open
Abstract
We report a theoretical study of the localized spatial magnetization configuration, which is a confined spin configuration of the target skyrmion/hopfion type in an antiferromagnet with perpendicular magnetic anisotropy, and then we solve the particular problem of self-oscillations of such a topological spin texture. Using the energy approach, a self-consistent account of inhomogeneity of the characteristics of the topological magnetic spin texture was carried out. On this basis, the equation of free oscillations of the confined spin configuration magnetization was derived and its quasi-classical solution was found. For a thin ring spin texture, the frequency, period of oscillations and relative amplitude of the main tone of oscillations are found. For the first time, we determined the topological mass, inertial mass and total energy of the main tone of oscillations of such spatial spin texture. The self-oscillatory process of a spatial spin texture is interpreted as a magnetic nano-oscillator.
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Affiliation(s)
- Victor S Gerasimchuk
- Faculty of Physics and Mathematics, National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute", Peremohy Ave. 37, Kyiv, 03056, Ukraine
| | - Yuri I Gorobets
- Faculty of Physics and Mathematics, National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute", Peremohy Ave. 37, Kyiv, 03056, Ukraine
- Department of Physics of Meso- and Nanocrystal Magnetic Structures, Institute of Magnetism, National Academy of Sciences of Ukraine and Ministry of Education and Science of Ukraine, Vernadsky Blvd. 36b, Kyiv, 03142, Ukraine
| | - Oksana Yu Gorobets
- Faculty of Physics and Mathematics, National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute", Peremohy Ave. 37, Kyiv, 03056, Ukraine
- Department of Physics of Meso- and Nanocrystal Magnetic Structures, Institute of Magnetism, National Academy of Sciences of Ukraine and Ministry of Education and Science of Ukraine, Vernadsky Blvd. 36b, Kyiv, 03142, Ukraine
| | - Igor V Gerasimchuk
- Faculty of Physics and Mathematics, National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute", Peremohy Ave. 37, Kyiv, 03056, Ukraine.
- Department of Physics of Meso- and Nanocrystal Magnetic Structures, Institute of Magnetism, National Academy of Sciences of Ukraine and Ministry of Education and Science of Ukraine, Vernadsky Blvd. 36b, Kyiv, 03142, Ukraine.
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4
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Liu Y, Watanabe H, Nagaosa N. Emergent Magnetomultipoles and Nonlinear Responses of a Magnetic Hopfion. PHYSICAL REVIEW LETTERS 2022; 129:267201. [PMID: 36608193 DOI: 10.1103/physrevlett.129.267201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 10/13/2022] [Accepted: 12/06/2022] [Indexed: 06/17/2023]
Abstract
The three-dimensional emergent magnetic field B^{e} of a magnetic hopfion gives rise to emergent magnetomultipoles in a similar manner to the multipoles of classical electromagnetic field. Here, we show that the nonlinear responses of a hopfion are characterized by its emergent magnetic toroidal moment T_{z}^{e}=1/2∫(r×B^{e})_{z}dV and emergent magnetic octupole component Γ^{e}=∫[(x^{2}+y^{2})B_{z}^{e}-xzB_{x}^{e}-yzB_{y}^{e}]dV. The hopfion exhibits nonreciprocal dynamics (nonlinear hopfion Hall effect) under an ac driving current applied along (perpendicular to) the direction of T_{z}^{e}. The sign of nonreciprocity and nonlinear Hall angle is determined by the polarity and chirality of hopfion. The nonlinear electrical transport induced by a magnetic hopfion is also discussed. This Letter reveals the vital roles of emergent magnetomultipoles in nonlinear hopfion dynamics and could stimulate further investigations on the dynamical responses of topological spin textures induced by emergent electromagnetic multipoles.
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Affiliation(s)
- Yizhou Liu
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
| | - Hikaru Watanabe
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
| | - Naoto Nagaosa
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
- Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan
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5
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McCray ARC, Li Y, Basnet R, Pandey K, Hu J, Phelan DP, Ma X, Petford-Long AK, Phatak C. Thermal Hysteresis and Ordering Behavior of Magnetic Skyrmion Lattices. NANO LETTERS 2022; 22:7804-7810. [PMID: 36129969 DOI: 10.1021/acs.nanolett.2c02275] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The physics of phase transitions in two-dimensional (2D) systems underpins research in diverse fields including statistical mechanics, nanomagnetism, and soft condensed matter. However, many aspects of 2D phase transitions are still not well understood, including the effects of interparticle potential, polydispersity, and particle shape. Magnetic skyrmions are chiral spin-structure quasi-particles that form two-dimensional lattices. Here, we show, by real-space imaging using in situ cryo-Lorentz transmission electron microscopy coupled with machine learning image analysis, the ordering behavior of Néel skyrmion lattices in van der Waals Fe3GeTe2. We demonstrate a distinct change in the skyrmion size distribution during field-cooling, which leads to a loss of lattice order and an evolution of the skyrmion liquid phase. Remarkably, the lattice order is restored during field heating and demonstrates a thermal hysteresis. This behavior is explained by the skyrmion energy landscape and demonstrates the potential to control the lattice order in 2D phase transitions.
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Affiliation(s)
- Arthur R C McCray
- Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
- Applied Physics Program, Northwestern University, Evanston, Illinois 60208, United States
| | - Yue Li
- Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Rabindra Basnet
- Department of Physics, University of Arkansas, Fayetteville, Arkansas 72701, United States
| | - Krishna Pandey
- Materials Science and Engineering Program, University of Arkansas, Fayetteville, Arkansas 72701, United States
| | - Jin Hu
- Department of Physics, University of Arkansas, Fayetteville, Arkansas 72701, United States
- Materials Science and Engineering Program, University of Arkansas, Fayetteville, Arkansas 72701, United States
| | - Daniel P Phelan
- Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Xuedan Ma
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Amanda K Petford-Long
- Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Charudatta Phatak
- Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
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6
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Hirosawa T, Klinovaja J, Loss D, Díaz SA. Laser-Controlled Real- and Reciprocal-Space Topology in Multiferroic Insulators. PHYSICAL REVIEW LETTERS 2022; 128:037201. [PMID: 35119897 DOI: 10.1103/physrevlett.128.037201] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 12/02/2021] [Accepted: 12/17/2021] [Indexed: 06/14/2023]
Abstract
Magnetic materials in which it is possible to control the topology of their magnetic order in real space or the topology of their magnetic excitations in reciprocal space are highly sought after as platforms for alternative data storage and computing architectures. Here we show that multiferroic insulators, owing to their magnetoelectric coupling, offer a natural and advantageous way to address these two different topologies using laser fields. We demonstrate that via a delicate balance between the energy injection from a high-frequency laser and dissipation, single skyrmions-archetypical topological magnetic textures-can be set into motion with a velocity and propagation direction that can be tuned by the laser field amplitude and polarization, respectively. Moreover, we uncover an ultrafast Floquet magnonic topological phase transition in a laser-driven skyrmion crystal and we propose a new diagnostic tool to reveal it using the magnonic thermal Hall conductivity.
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Affiliation(s)
- Tomoki Hirosawa
- Department of Physics, University of Tokyo, Bunkyo, Tokyo 113-0033, Japan
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Jelena Klinovaja
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Daniel Loss
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Sebastián A Díaz
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
- Faculty of Physics, University of Duisburg-Essen, 47057 Duisburg, Germany
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7
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Wu Y, Wen H, Chen W, Zheng Y. Microdynamic Study of Spin-Lattice Coupling Effects on Skyrmion Transport. PHYSICAL REVIEW LETTERS 2021; 127:097201. [PMID: 34506159 DOI: 10.1103/physrevlett.127.097201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 05/30/2021] [Accepted: 07/27/2021] [Indexed: 06/13/2023]
Abstract
Skyrmion transport fundamentally determines the speed, energy consumption, and functionality of skyrmion-based spintronic devices, attracting considerable attention. Recent experimental studies found there is a migration barrier for the thermal activated transport of a skyrmion, which is speculated to be induced by the pinning effects of crystalline defects. In this Letter, we propose an alternative source of migration barrier for skyrmion transport, i.e., a local lattice distortion field due to spin-lattice coupling, which can lead to the same Arrhenius diffusion behavior in defect-free skyrmion materials. By performing spin-lattice dynamics simulations, we study the microdynamic insight into the influence of local lattice distortion field, which refreshes the mechanistic understanding on skyrmion transport.
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Affiliation(s)
- Yifeng Wu
- Centre for Physical Mechanics and Biophysics, School of Physics, Sun Yat-sen University, Guangzhou 510275, China
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, Guangzhou 510275, China
| | - Haohua Wen
- Centre for Physical Mechanics and Biophysics, School of Physics, Sun Yat-sen University, Guangzhou 510275, China
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, Guangzhou 510275, China
- Sino-French Institute of Nuclear Engineering and Technology, Sun Yat-sen University, Zhuhai 519082, China
| | - Weijin Chen
- Centre for Physical Mechanics and Biophysics, School of Physics, Sun Yat-sen University, Guangzhou 510275, China
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, Guangzhou 510275, China
- School of Materials, Sun Yat-sen University, Shenzhen 518107, China
| | - Yue Zheng
- Centre for Physical Mechanics and Biophysics, School of Physics, Sun Yat-sen University, Guangzhou 510275, China
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, Guangzhou 510275, China
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8
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Psaroudaki C, Panagopoulos C. Skyrmion Qubits: A New Class of Quantum Logic Elements Based on Nanoscale Magnetization. PHYSICAL REVIEW LETTERS 2021; 127:067201. [PMID: 34420323 DOI: 10.1103/physrevlett.127.067201] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 06/30/2021] [Indexed: 05/05/2023]
Abstract
We introduce a new class of primitive building blocks for realizing quantum logic elements based on nanoscale magnetization textures called skyrmions. In a skyrmion qubit, information is stored in the quantum degree of helicity, and the logical states can be adjusted by electric and magnetic fields, offering a rich operation regime with high anharmonicity. By exploring a large parameter space, we propose two skyrmion qubit variants depending on their quantized state. We discuss appropriate microwave pulses required to generate single-qubit gates for quantum computing, and skyrmion multiqubit schemes for a scalable architecture with tailored couplings. Scalability, controllability by microwave fields, operation time scales, and readout by nonvolatile techniques converge to make the skyrmion qubit highly attractive as a logical element of a quantum processor.
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Affiliation(s)
- Christina Psaroudaki
- Department of Physics and Institute for Quantum Information and Matter, California Institute of Technology, Pasadena, California 91125, USA
- Institute for Theoretical Physics, University of Cologne, D-50937 Cologne, Germany
| | - Christos Panagopoulos
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link 637371, Singapore
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9
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Eilmsteiner D, Wang XG, Chotorlishvili L, Paischer S, Hoffmann M, Buczek P, Ernst A. Asymmetry in the propagation of vortex domain wall artificial skyrmion composite system. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:185803. [PMID: 33711837 DOI: 10.1088/1361-648x/abee39] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 03/12/2021] [Indexed: 06/12/2023]
Abstract
We studied the propagation of an artificial skyrmion coupled to the vortex domain wall (VDW). We discovered the following effect: depending on the propagation's direction, the dynamics of the coupled skyrmion VDW can be faster than the isolated VDW's velocity. The reason for such behavior is the structural distortion that occurs in the coupled system. We interpret the numerical results in terms of the modified Thiele's equation. In particular, increasing the Thiele's equation counteractive coefficient leads to the perfect fitting with the micromagnetic simulation results.
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Affiliation(s)
- D Eilmsteiner
- Institute for Theoretical Physics, Johannes Kepler University Linz, 4040 Linz, Austria
| | - Xi-Guang Wang
- School of Physics and Electronics, Central South University, Changsha 410083, People's Republic of China
| | - L Chotorlishvili
- Institute für Physik, Martin-Luther Universität Halle-Wittenberg, D-06120 Halle/Saale, Germany
| | - S Paischer
- Institute for Theoretical Physics, Johannes Kepler University Linz, 4040 Linz, Austria
| | - M Hoffmann
- Institute for Theoretical Physics, Johannes Kepler University Linz, 4040 Linz, Austria
| | - P Buczek
- Department of Engineering and Computer Sciences, Hamburg University of Applied Sciences, Berliner Tor 7, 20099 Hamburg, Germany
| | - A Ernst
- Institute for Theoretical Physics, Johannes Kepler University Linz, 4040 Linz, Austria
- Max Planck Institute of Microstructure Physics, 06120 Halle, Germany
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10
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Chen J, Hu J, Yu H. Chiral Emission of Exchange Spin Waves by Magnetic Skyrmions. ACS NANO 2021; 15:4372-4379. [PMID: 33645959 DOI: 10.1021/acsnano.0c07805] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Spin waves or their quanta magnons raise the prospect to act as information carriers in the absence of Joule heating. The challenge to excite spin waves with nanoscale wavelengths free of nanolithography becomes a critical bottleneck for the application of nanomagnonics. Magnetic skyrmions are chiral magnetic textures at the nanoscale. In this work, short-wavelength exchange spin waves are demonstrated to be chirally emitted in a low damping magnetic insulating thin film by magnetic skyrmions. The spin-wave chirality originates from the chiral spin pumping effect and is determined by the cross product of the magnetization orientation and the film normal direction. The Halbach effect explains the enhancement or attenuation of the spin-wave amplitude with a reversed sign of the Dyzaloshinskii-Moriya interaction. Controllable spin-wave propagation is demonstrated by rotating a moderate applied field. Our findings are key for building compact low-power nanomagnonic devices based on intrinsic nanoscale magnetic textures.
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Affiliation(s)
- Jilei Chen
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- Fert Beijing Institute, School of Integrated Circuit Science and Engineering, Beijing Advanced Innovation Center for Big Data and Brain Computing, Beihang University, Beijing 100191, China
| | - Junfeng Hu
- Fert Beijing Institute, School of Integrated Circuit Science and Engineering, Beijing Advanced Innovation Center for Big Data and Brain Computing, Beihang University, Beijing 100191, China
| | - Haiming Yu
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- Fert Beijing Institute, School of Integrated Circuit Science and Engineering, Beijing Advanced Innovation Center for Big Data and Brain Computing, Beihang University, Beijing 100191, China
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11
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Tejo F, Velozo F, Elías RG, Escrig J. Oscillations of skyrmion clusters in Co/Pt multilayer nanodots. Sci Rep 2020; 10:16517. [PMID: 33020538 PMCID: PMC7536206 DOI: 10.1038/s41598-020-73458-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 09/14/2020] [Indexed: 11/30/2022] Open
Abstract
In this work we study the oscillations of the skyrmion cores in a multilayer nanodot as a function of the number of skyrmions hosted in the system. When all the skyrmions in the nanodot have the same core radius, and after applying a perpendicular spin-polarized current, a relaxation process takes place towards an equilibrium configuration that is accompanied by coherent damped oscillations of the skyrmion cores, whose frequency depends on the number of skyrmions present in the nanodot. Additionally, we found that the oscillation frequency is directly related to the total energy of the system.
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Affiliation(s)
- Felipe Tejo
- Departamento de Física, Universidad de Santiago de Chile, 9170124, Santiago, Chile. .,Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, 28049, Madrid, Spain.
| | - Felipe Velozo
- Departamento de Física, Universidad de Santiago de Chile, 9170124, Santiago, Chile
| | - Ricardo Gabriel Elías
- Departamento de Física, Universidad de Santiago de Chile, 9170124, Santiago, Chile.,Center for the Development of Nanoscience and Nanotechnology, 9170124, Santiago, Chile
| | - Juan Escrig
- Departamento de Física, Universidad de Santiago de Chile, 9170124, Santiago, Chile.,Center for the Development of Nanoscience and Nanotechnology, 9170124, Santiago, Chile
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12
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Díaz SA, Hirosawa T, Loss D, Psaroudaki C. Spin Wave Radiation by a Topological Charge Dipole. NANO LETTERS 2020; 20:6556-6562. [PMID: 32812768 DOI: 10.1021/acs.nanolett.0c02192] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The use of spin waves (SWs) as data carriers in spintronic and magnonic logic devices offers operation at low power consumption, free of Joule heating. Nevertheless, the controlled emission and propagation of SWs in magnetic materials remains a significant challenge. Here, we propose that skyrmion-antiskyrmion bilayers form topological charge dipoles and act as efficient sub-100 nm SW emitters when excited by in-plane ac magnetic fields. The propagating SWs have a preferred radiation direction, with clear dipole signatures in their radiation pattern, suggesting that the bilayer forms a SW antenna. Bilayers with the same topological charge radiate SWs with spiral and antispiral spatial profiles, enlarging the class of SW patterns. We demonstrate that the characteristics of the emitted SWs are linked to the topology of the source, allowing for full control of the SW features, including their amplitude, preferred direction of propagation, and wavelength.
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Affiliation(s)
- Sebastián A Díaz
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Tomoki Hirosawa
- Department of Physics, University of Tokyo, Bunkyo, Tokyo 113-0033, Japan
| | - Daniel Loss
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Christina Psaroudaki
- Department of Physics, California Institute of Technology, Pasadena, California 91125, United States
- Institute for Theoretical Physics, University of Cologne, D-50937 Cologne, Germany
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13
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Blachowicz T, Ehrmann A. Magnetic Elements for Neuromorphic Computing. Molecules 2020; 25:E2550. [PMID: 32486173 PMCID: PMC7321415 DOI: 10.3390/molecules25112550] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 05/18/2020] [Accepted: 05/28/2020] [Indexed: 01/02/2023] Open
Abstract
Neuromorphic computing is assumed to be significantly more energy efficient than, and at the same time expected to outperform, conventional computers in several applications, such as data classification, since it overcomes the so-called von Neumann bottleneck. Artificial synapses and neurons can be implemented into conventional hardware using new software, but also be created by diverse spintronic devices and other elements to completely avoid the disadvantages of recent hardware architecture. Here, we report on diverse approaches to implement neuromorphic functionalities in novel hardware using magnetic elements, published during the last years. Magnetic elements play an important role in neuromorphic computing. While other approaches, such as optical and conductive elements, are also under investigation in many groups, magnetic nanostructures and generally magnetic materials offer large advantages, especially in terms of data storage, but they can also unambiguously be used for data transport, e.g., by propagation of skyrmions or domain walls. This review underlines the possible applications of magnetic materials and nanostructures in neuromorphic systems.
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Affiliation(s)
- Tomasz Blachowicz
- Institute of Physics–Center for Science and Education, Silesian University of Technology, 44-100 Gliwice, Poland;
| | - Andrea Ehrmann
- Faculty of Engineering and Mathematics, Bielefeld University of Applied Sciences, 33619 Bielefeld, Germany
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14
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Psaroudaki C, Loss D. Quantum Depinning of a Magnetic Skyrmion. PHYSICAL REVIEW LETTERS 2020; 124:097202. [PMID: 32202863 DOI: 10.1103/physrevlett.124.097202] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 02/14/2020] [Indexed: 05/05/2023]
Abstract
We investigate the quantum depinning of a weakly driven skyrmion out of an impurity potential in a mesoscopic magnetic insulator. For small barrier height, the Magnus force dynamics dominates over the inertial term, and the problem is reduced to a massless charged particle in a strong magnetic field. The universal form of the WKB exponent, the rate of tunneling, and the crossover temperature between thermal and quantum tunneling are provided, independently of the detailed form of the pinning potential. The results are discussed in terms of macroscopic parameters of the insulator Cu_{2}OSeO_{3} and various skyrmion radii. We demonstrate that small enough magnetic skyrmions, with a radius of ∼10 lattice sites, consisting of some thousands of spins, can behave as quantum objects at low temperatures in the millikelvin regime.
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Affiliation(s)
- Christina Psaroudaki
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Daniel Loss
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
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15
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Kim KW, Lee SW, Moon JH, Go G, Manchon A, Lee HW, Everschor-Sitte K, Lee KJ. Unidirectional Magnon-Driven Domain Wall Motion Due to the Interfacial Dzyaloshinskii-Moriya Interaction. PHYSICAL REVIEW LETTERS 2019; 122:147202. [PMID: 31050478 DOI: 10.1103/physrevlett.122.147202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 11/08/2018] [Indexed: 06/09/2023]
Abstract
We demonstrate a unidirectional motion of a quasiparticle without explicit symmetry breaking along the space-time coordinate of the particle motion. This counterintuitive behavior originates from a combined action of two intrinsic asymmetries in the other two directions. We realize this idea with the magnon-driven motion of a magnetic domain wall in thin films with interfacial asymmetry. Contrary to previous studies, the domain wall moves along the same direction regardless of the magnon-flow direction. Our general symmetry analysis and numerical simulation reveal that the odd order contributions from the interfacial asymmetry is unidirectional, which is dominant over bidirectional contributions in the realistic regime. We develop a simple analytic theory on the unidirectional motion, which provides an insightful description of this counterintuitive phenomenon.
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Affiliation(s)
- Kyoung-Whan Kim
- Institute of Physics, Johannes Gutenberg University Mainz, 55099 Mainz, Germany
- Center for Spintronics, Korea Institute of Science and Technology, Seoul 02792, Korea
| | - Seo-Won Lee
- Department of Materials Science and Engineering, Korea University, Seoul 02841, Korea
| | - Jung-Hwan Moon
- Department of Materials Science and Engineering, Korea University, Seoul 02841, Korea
| | - Gyungchoon Go
- Department of Materials Science and Engineering, Korea University, Seoul 02841, Korea
| | - Aurélien Manchon
- King Abdullah University of Science and Technology (KAUST), Physical Science and Engineering Division (PSE), Thuwal 23955-6900, Saudi Arabia
- King Abdullah University of Science and Technology (KAUST), Computer, Electrical and Mathematical Science and Engineering Division (CEMSE), Thuwal 23955-6900, Saudi Arabia
| | - Hyun-Woo Lee
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Korea
| | | | - Kyung-Jin Lee
- Department of Materials Science and Engineering, Korea University, Seoul 02841, Korea
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Korea
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