1
|
Zhang Y, Xu T, Jiang W, Yu R, Chen Z. Quantification of Hybrid Topological Spin Textures and Their Nanoscale Fluctuations in Ferrimagnets. NANO LETTERS 2024; 24:2727-2734. [PMID: 38395052 DOI: 10.1021/acs.nanolett.3c04409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/25/2024]
Abstract
Noncolinear spin textures, including chiral stripes and skyrmions, have shown great potential in spintronics. Basic configurations of spin textures are either Bloch or Néel types, and the intermediate hybrid type has rarely been reported. A major challenge in identifying hybrid spin textures is to quantitatively determine the hybrid angle, especially in ferrimagnets with weak net magnetization. Here, we develop an approach to quantify magnetic parameters, including chirality, saturation magnetization, domain wall width, and hybrid angle with sub-5 nm spatial resolution, based on Lorentz four-dimensional scanning transmission electron microscopy (Lorentz 4D-STEM). We find strong nanometer-scale variations in the hybrid angle and domain wall width within structurally and chemically homogeneous FeGd ferrimagnetic films. These variations fluctuate during different magnetization circles, revealing intrinsic local magnetization inhomogeneities. Furthermore, hybrid skyrmions can also be nucleated in FeGd films. These analyses demonstrate that the Lorentz 4D-STEM is a quantitative tool for exploring complex spin textures.
Collapse
Affiliation(s)
- Yuxuan Zhang
- School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
- MOE Key Laboratory of Advanced Materials, Tsinghua University, Beijing 100084, China
- State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, Beijing 100084, China
| | - Teng Xu
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
| | - Wanjun Jiang
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
| | - Rong Yu
- School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
- MOE Key Laboratory of Advanced Materials, Tsinghua University, Beijing 100084, China
- State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, Beijing 100084, China
| | - Zhen Chen
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| |
Collapse
|
2
|
Bera S. Role of isotropic and anisotropic Dzyaloshinskii-Moriya interaction on skyrmions, merons and antiskyrmions in the Cnvsymmetric system. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:195805. [PMID: 38316047 DOI: 10.1088/1361-648x/ad266f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Accepted: 02/05/2024] [Indexed: 02/07/2024]
Abstract
The lattice Hamiltonian with the presence of a chiral magnetic isotropic Dzyaloshinskii-Moriya interaction (DMI) in a square and hexagonal lattice is numerically solved to give the full phase diagram consisting of skyrmions and merons in different parameter planes. The phase diagram provides the actual regions of analytically unresolved asymmetric skyrmions and merons, and it is found that these regions are substantially larger than those of symmetric skyrmions and merons. With magnetic field, a change from meron or spin spiral (SS) to skyrmion is seen. The complete phase diagram for theCnvsymmetric system with anisotropic DMI is drawn and it is shown that this DMI helps to change the SS propagation direction. Finally, the well-defined region of a thermodynamically stable antiskyrmion phase in theCnvsymmetric system is shown.
Collapse
Affiliation(s)
- Sandip Bera
- Department of Physics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 1A7, Canada
| |
Collapse
|
3
|
Huang Z, McCray ARC, Li Y, Morrow DJ, Qian EK, Young Chung D, Kanatzidis MG, Phatak C, Ma X. Raman Shifts in Two-Dimensional van der Waals Magnets Reveal Magnetic Texture Evolution. NANO LETTERS 2024; 24:1531-1538. [PMID: 38286029 DOI: 10.1021/acs.nanolett.3c03923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2024]
Abstract
Two-dimensional (2D) van der Waals magnets comprise rich physics that can be exploited for spintronic applications. We investigate the interplay between spin-phonon coupling and spin textures in a 2D van der Waals magnet by combining magneto-Raman spectroscopy with cryogenic Lorentz transmission electron microscopy. We find that when stable skyrmion bubbles are formed in the 2D magnet, a field-dependent Raman shift can be observed, and this shift is absent for the 2D magnet prepared in its ferromagnetic state. Correlating these observations with numerical simulations that take into account field-dependent magnetic textures and spin--phonon coupling in the 2D magnet, we associate the Raman shift to field-induced modulations of the skyrmion bubbles and derive the existence of inhomogeneity in the skyrmion textures over the film thickness.
Collapse
Affiliation(s)
- Zhengjie Huang
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - 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
| | - Darien J Morrow
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Eric K Qian
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Duck Young Chung
- Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Mercouri G Kanatzidis
- Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Charudatta Phatak
- 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
- Consortium for Advanced Science and Engineering, University of Chicago, Chicago, Illinois 60637, United States
- Northwestern-Argonne Institute of Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| |
Collapse
|
4
|
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.
Collapse
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
| |
Collapse
|
5
|
Song Y, Xu T, Zhao G, Xu Y, Zhong Z, Zheng X, Shi N, Zhou C, Hao Y, Huang Q, Xing X, Zhang Y, Chen J. High-density, spontaneous magnetic biskyrmions induced by negative thermal expansion in ferrimagnets. SCIENCE ADVANCES 2023; 9:eadi1984. [PMID: 37672584 PMCID: PMC10482331 DOI: 10.1126/sciadv.adi1984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 08/04/2023] [Indexed: 09/08/2023]
Abstract
Magnetic skyrmions are topologically protected quasiparticles that are promising for applications in spintronics. However, the low stability of most magnetic skyrmions leads to either a narrow temperature range in which they can exist, a low density of skyrmions, or the need for an external magnetic field, which greatly limits their wide application. In this study, high-density, spontaneous magnetic biskyrmions existing within a wide temperature range and without the need for a magnetic field were formed in ferrimagnets owing to the existence of a negative thermal expansion of the lattice. Moreover, a strong connection between the atomic-scale ferrimagnetic structure and nanoscale magnetic domains in Ho(Co,Fe)3 was revealed via in situ neutron powder diffraction and Lorentz transmission electron microscopy measurements. The critical role of the negative thermal expansion in generating biskyrmions in HoCo3 based on the magnetoelastic coupling effect is further demonstrated by comparing the behavior of HoCo2.8Fe0.2 with a positive thermal expansion.
Collapse
Affiliation(s)
- Yuzhu Song
- Beijing Advanced Innovation Center for Materials Genome Engineering, Department of Physical Chemistry, University of Science and Technology Beijing, Beijing 100083, China
| | - Tiankuo Xu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Guoping Zhao
- College of Physics and Electronic Engineering and Institute of Solid State Physics, Sichuan Normal University, Chengdu 610066, China
| | - Yuanji Xu
- Institute for Applied Physics, University of Science and Technology Beijing, Beijing 100083, China
| | - Zhicheng Zhong
- Key Laboratory of Magnetic Materials Devices & Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Xinqi Zheng
- School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Naike Shi
- Beijing Advanced Innovation Center for Materials Genome Engineering, Department of Physical Chemistry, University of Science and Technology Beijing, Beijing 100083, China
| | - Chang Zhou
- State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China
| | - Yiqing Hao
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
| | - Qingzhen Huang
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg MD, 20899-6102, USA
| | - Xianran Xing
- Institute of Solid State Chemistry, University of Science and Technology Beijing, Beijing 100083, China
| | - Ying Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jun Chen
- Beijing Advanced Innovation Center for Materials Genome Engineering, Department of Physical Chemistry, University of Science and Technology Beijing, Beijing 100083, China
| |
Collapse
|
6
|
Du K, Huang FT, Gamage K, Yang J, Mostovoy M, Cheong SW. Strain-Control of Cycloidal Spin Order in a Metallic Van der Waals Magnet. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2303750. [PMID: 37358066 DOI: 10.1002/adma.202303750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 06/06/2023] [Indexed: 06/27/2023]
Abstract
The manipulation of magnetism through strain control is a captivating area of research with potential applications for low-power devices that do not require dissipative currents. Recent investigations of insulating multiferroics have unveiled tunable relationships among polar lattice distortions, Dzyaloshinskii-Moriya interactions (DMI), and cycloidal spin orders that break inversion symmetry. These findings have raised the possibility of utilizing strain or strain gradient to manipulate intricate magnetic states by changing polarization. However, the effectiveness of manipulating cycloidal spin orders in "metallic" materials with screened magnetism-relevant electric polarization remains uncertain. In this study, the reversible strain control of cycloidal spin textures in a metallic van der Waals magnet, Cr1/3 TaS2 , through the modulation of polarization and DMI induced by strain is demonstrated. With thermally-induced biaxial strains and isothermally-applied uniaxial strains, systematic manipulation of the sign and wavelength of the cycloidal spin textures is realized, respectively. Additionally, unprecedented reflectivity reduction under strain and domain modification at a record-low current density are also discovered. These findings establish a connection between polarization and cycloidal spins in metallic materials and present a new avenue for utilizing the remarkable tunability of cycloidal magnetic textures and optical functionality in van der Waals metals with strain.
Collapse
Affiliation(s)
- Kai Du
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey, 08854, USA
| | - Fei-Ting Huang
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey, 08854, USA
| | - Kasun Gamage
- Department of Physics, New Jersey Institute of Technology, Newark, New Jersey, 07102, USA
| | - Junjie Yang
- Department of Physics, New Jersey Institute of Technology, Newark, New Jersey, 07102, USA
| | - Maxim Mostovoy
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, Groningen, 9747AG, The Netherlands
| | - Sang-Wook Cheong
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey, 08854, USA
| |
Collapse
|
7
|
Zelent M, Moalic M, Mruczkiewicz M, Li X, Zhou Y, Krawczyk M. Stabilization and racetrack application of asymmetric Néel skyrmions in hybrid nanostructures. Sci Rep 2023; 13:13572. [PMID: 37604926 PMCID: PMC10442414 DOI: 10.1038/s41598-023-40236-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 08/07/2023] [Indexed: 08/23/2023] Open
Abstract
Magnetic skyrmions, topological quasiparticles, are small stable magnetic textures that possess intriguing properties and potential for data storage applications. Hybrid nanostructures comprised of skyrmions and soft magnetic material can offer additional advantages for developing skyrmion-based spintronic and magnonic devices. We show that a Néel-type skyrmion confined within a nanodot placed on top of a ferromagnetic in-plane magnetized stripe produces a unique and compelling platform for exploring the mutual coupling between magnetization textures. The skyrmion induces an imprint upon the stripe, which, in turn, asymmetrically squeezes the skyrmion in the dot, increasing their size and the range of skyrmion stability at small values of Dzyaloshinskii-Moriya interaction, as well as introducing skyrmion bi-stability. Finally, by exploiting the properties of the skyrmion in a hybrid system, we demonstrate unlimited skyrmion transport along a racetrack, free of the skyrmion Hall effect.
Collapse
Affiliation(s)
- Mateusz Zelent
- Faculty of Physics, Institute of Spintronics and Quantum Information, Adam Mickiewicz University, Poznan, ul. Uniwersytetu Poznańskiego 2, 61-614, Poznan, Poland.
| | - Mathieu Moalic
- Faculty of Physics, Institute of Spintronics and Quantum Information, Adam Mickiewicz University, Poznan, ul. Uniwersytetu Poznańskiego 2, 61-614, Poznan, Poland
| | - Michal Mruczkiewicz
- Institute of Electrical Engineering, Slovak Academy of Sciences, Dubravska cesta 9, Bratislava, 841-04, Slovakia
- Centre For Advanced Materials Application CEMEA, Slovak Academy of Sciences, Dubravska cesta 9, Bratislava, 845 11, Slovakia
| | - Xiaoguang Li
- College of Engineering Physics, Shenzhen Technology University, Shenzhen, 518118, China
| | - Yan Zhou
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, 518172, China
| | - Maciej Krawczyk
- Faculty of Physics, Institute of Spintronics and Quantum Information, Adam Mickiewicz University, Poznan, ul. Uniwersytetu Poznańskiego 2, 61-614, Poznan, Poland
| |
Collapse
|
8
|
Han MG, Camino F, Vorobyev PA, Garlow J, Rov R, Söhnel T, Seidel J, Mostovoy M, Tretiakov OA, Zhu Y. Hysteretic Responses of Skyrmion Lattices to Electric Fields in Magnetoelectric Cu 2OSeO 3. NANO LETTERS 2023; 23:7143-7149. [PMID: 37523664 DOI: 10.1021/acs.nanolett.3c02034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/02/2023]
Abstract
Electric field control of topologically nontrivial magnetic textures, such as skyrmions, provides a paradigm shift for future spintronics beyond the current silicon-based technology. While significant progress has been made by X-ray and neutron scattering studies, direct observation of such nanoscale spin structures and their dynamics driven by external electric fields remains a challenge in understanding the underlying mechanisms and harness functionalities. Here, using Lorentz transmission electron microscopy combined with in situ electric and magnetic fields at liquid helium temperatures, we report the crystallographic orientation-dependent skyrmion responses to electric fields in thin slabs of magnetoelectric Cu2OSeO3. We show that electric fields not only stabilize the hexagonally packed skyrmion lattices in the entire sample in a hysteretic manner but also induce the rotation of their reciprocal vector discretely by 30°. The nonvolatile and energy-efficient skyrmion lattice control by electric fields demonstrated in this work provides an important foundation for designing skyrmion-based qubits and memory devices.
Collapse
Affiliation(s)
- Myung-Geun Han
- Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Fernando Camino
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Pavel A Vorobyev
- School of Physics, The University of New South Wales, Sydney 2052, Australia
| | - Joseph Garlow
- Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Rosanna Rov
- School of Chemical Sciences, University of Auckland, Auckland 1142, New Zealand
- The MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington 6012, New Zealand
| | - Tilo Söhnel
- School of Chemical Sciences, University of Auckland, Auckland 1142, New Zealand
- The MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington 6012, New Zealand
| | - Jan Seidel
- Department of Materials Science and Engineering, The University of New South Wales, Sydney 2052, Australia
| | - Maxim Mostovoy
- Department of Physics, University of Groningen, Groningen 9747, The Netherlands
| | - Oleg A Tretiakov
- School of Physics, The University of New South Wales, Sydney 2052, Australia
| | - Yimei Zhu
- Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, New York 11973, United States
| |
Collapse
|
9
|
Truc B, Sapozhnik AA, Tengdin P, Viñas Boström E, Schönenberger T, Gargiulo S, Madan I, LaGrange T, Magrez A, Verdozzi C, Rubio A, Rønnow HM, Carbone F. Light-Induced Metastable Hidden Skyrmion Phase in the Mott Insulator Cu 2 OSeO 3. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2304197. [PMID: 37282751 DOI: 10.1002/adma.202304197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Indexed: 06/08/2023]
Abstract
The discovery of a novel long-lived metastable skyrmion phase in the multiferroic insulator Cu2 OSeO3 visualized with Lorentz transmission electron microscopy for magnetic fields below the equilibrium skyrmion pocket is reported. This phase can be accessed by exciting the sample non-adiabatically with near-infrared femtosecond laser pulses and cannot be reached by any conventional field-cooling protocol, referred as a hidden phase. From the strong wavelength dependence of the photocreation process and via spin-dynamics simulations, the magnetoelastic effect is identified as the most likely photocreation mechanism. This effect results in a transient modification of the magnetic free energy landscape extending the equilibrium skyrmion pocket to lower magnetic fields. The evolution of the photoinduced phase is monitored for over 15 min and no decay is found. Because such a time is much longer than the duration of any transient effect induced by a laser pulse in a material, it is assumed that the newly discovered skyrmion state is stable for practical purposes, thus breaking ground for a novel approach to control magnetic state on demand at ultrafast timescales and drastically reducing heat dissipation relevant for next-generation spintronic devices.
Collapse
Affiliation(s)
- Benoit Truc
- Laboratory for Ultrafast Microscopy and Electron Scattering, Institute of Physics, École Polytechnique Fédérale de Lausanne, Lausanne, 1015, Switzerland
| | - Alexey A Sapozhnik
- Laboratory for Ultrafast Microscopy and Electron Scattering, Institute of Physics, École Polytechnique Fédérale de Lausanne, Lausanne, 1015, Switzerland
| | - Phoebe Tengdin
- Laboratory for Ultrafast Microscopy and Electron Scattering, Institute of Physics, École Polytechnique Fédérale de Lausanne, Lausanne, 1015, Switzerland
| | - Emil Viñas Boström
- Max Planck Institute for the Structure and Dynamics of Matter, 22761, Hamburg, Germany
| | - Thomas Schönenberger
- Laboratory for Quantum Magnetism, Institute of Physics, École Polytechnique Fédérale de Lausanne, Lausanne, 1015, Switzerland
| | - Simone Gargiulo
- Laboratory for Ultrafast Microscopy and Electron Scattering, Institute of Physics, École Polytechnique Fédérale de Lausanne, Lausanne, 1015, Switzerland
| | - Ivan Madan
- Laboratory for Ultrafast Microscopy and Electron Scattering, Institute of Physics, École Polytechnique Fédérale de Lausanne, Lausanne, 1015, Switzerland
| | - Thomas LaGrange
- Laboratory for Ultrafast Microscopy and Electron Scattering, Institute of Physics, École Polytechnique Fédérale de Lausanne, Lausanne, 1015, Switzerland
| | - Arnaud Magrez
- Crystal Growth Facility, Institute of Physics, École Polytechnique Fédérale de Lausanne, Lausanne, 1015, Switzerland
| | - Claudio Verdozzi
- Division of Mathematical Physics and ETSF, Lund University, Lund, 223 63, Sweden
| | - Angel Rubio
- Max Planck Institute for the Structure and Dynamics of Matter, 22761, Hamburg, Germany
- Center for Computational Quantum Physics (CCQ), The Flatiron Institute, New York, 10010, USA
| | - Henrik M Rønnow
- Laboratory for Quantum Magnetism, Institute of Physics, École Polytechnique Fédérale de Lausanne, Lausanne, 1015, Switzerland
| | - Fabrizio Carbone
- Laboratory for Ultrafast Microscopy and Electron Scattering, Institute of Physics, École Polytechnique Fédérale de Lausanne, Lausanne, 1015, Switzerland
| |
Collapse
|
10
|
Kong D, Kovács A, Charilaou M, Zheng F, Wang L, Han X, Dunin-Borkowski RE. Direct observation of tensile-strain-induced nanoscale magnetic hardening. Nat Commun 2023; 14:3963. [PMID: 37407558 DOI: 10.1038/s41467-023-39650-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 06/22/2023] [Indexed: 07/07/2023] Open
Abstract
Magnetoelasticity is the bond between magnetism and mechanics, but the intricate mechanisms via which magnetic states change due to mechanical strain remain poorly understood. Here, we provide direct nanoscale observations of how tensile strain modifies magnetic domains in a ferromagnetic Ni thin plate using in situ Fresnel defocus imaging, off-axis electron holography and a bimetallic deformation device. We present quantitative measurements of magnetic domain wall structure and its transformations as a function of strain. We observe the formation and dissociation of strain-induced periodic 180° magnetic domain walls perpendicular to the strain axis. The magnetization transformation exhibits stress-determined directional sensitivity and is reversible and tunable through the size of the nanostructure. In this work, we provide direct evidence for expressive and deterministic magnetic hardening in ferromagnetic nanostructures, while our experimental approach allows quantifiable local measurements of strain-induced changes in the magnetic states of nanomaterials.
Collapse
Affiliation(s)
- Deli Kong
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52428, Jülich, Germany
- School of Physics and Optoelectronics, Faculty of Science, Beijing University of Technology, 100124, Beijing, China
| | - András Kovács
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52428, Jülich, Germany.
| | - Michalis Charilaou
- Department of Physics, University of Louisiana at Lafayette, 70504, Lafayette, Louisiana, USA
| | - Fengshan Zheng
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52428, Jülich, Germany
- Spin-X Institute, Electron Microscopy Center, School of Physics and Optoelectronics, State Key Laboratory of Luminescent Materials and Devices, Guangdong-Hong-Kong-Macao Joint Laboratory of Optoelectronic and Magnetic Functional Materials, South China University of Technology, 511442, Guangzhou, China
| | - Lihua Wang
- Institute of Microstructure and Properties of Advanced Materials, Beijing University of Technology, 100124, Beijing, China
| | - Xiaodong Han
- Institute of Microstructure and Properties of Advanced Materials, Beijing University of Technology, 100124, Beijing, China.
| | - Rafal E Dunin-Borkowski
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52428, Jülich, Germany
| |
Collapse
|
11
|
Nomura T, Zhang XX, Takagi R, Karube K, Kikkawa A, Taguchi Y, Tokura Y, Zherlitsyn S, Kohama Y, Seki S. Nonreciprocal Phonon Propagation in a Metallic Chiral Magnet. PHYSICAL REVIEW LETTERS 2023; 130:176301. [PMID: 37172228 DOI: 10.1103/physrevlett.130.176301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 04/06/2023] [Indexed: 05/14/2023]
Abstract
The phonon magnetochiral effect (MChE) is the nonreciprocal acoustic and thermal transports of phonons caused by the simultaneous breaking of the mirror and time-reversal symmetries. So far, the phonon MChE has been observed only in a ferrimagnetic insulator Cu_{2}OSeO_{3}, where the nonreciprocal response disappears above the Curie temperature of 58 K. Here, we study the nonreciprocal acoustic properties of a room-temperature ferromagnet Co_{9}Zn_{9}Mn_{2} for unveiling the phonon MChE close to room temperature. Surprisingly, the nonreciprocity in this metallic compound is enhanced at higher temperatures and observed up to 250 K. This clear contrast between insulating Cu_{2}OSeO_{3} and metallic Co_{9}Zn_{9}Mn_{2} suggests that metallic magnets have a mechanism to enhance the nonreciprocity at higher temperatures. From the ultrasound and microwave-spectroscopy experiments, we conclude that the magnitude of the phonon MChE of Co_{9}Zn_{9}Mn_{2} mostly depends on the Gilbert damping, which increases at low temperatures and hinders the magnon-phonon hybridization. Our results suggest that the phonon nonreciprocity could be further enhanced by engineering the magnon band of materials.
Collapse
Affiliation(s)
- T Nomura
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
- Tokyo Denki University, Adachi, Tokyo 120-8551, Japan
| | - X-X Zhang
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - R Takagi
- Department of Applied Physics, The University of Tokyo, Tokyo 113-8656, Japan
- PRESTO, Japan Science and Technology Agency (JST), Kawaguchi 332-0012, Japan
| | - K Karube
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - A Kikkawa
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - Y Taguchi
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - Y Tokura
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
- Department of Applied Physics, The University of Tokyo, Tokyo 113-8656, Japan
- Tokyo College, University of Tokyo, Tokyo 113-8656, Japan
| | - S Zherlitsyn
- Hochfeld-Magnetlabor Dresden (HLD-EMFL), Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
| | - Y Kohama
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - S Seki
- Department of Applied Physics, The University of Tokyo, Tokyo 113-8656, Japan
- PRESTO, Japan Science and Technology Agency (JST), Kawaguchi 332-0012, Japan
| |
Collapse
|
12
|
Chen R, Xu F, Cui Q, Liang J, Zhou Y, Wang N, Pan F, Xue F, Yang H, Song C. Anisotropic interlayer Dzyaloshinskii-Moriya interactions in synthetic ferromagnetic multilayers. Sci Bull (Beijing) 2023; 68:878-882. [PMID: 37080851 DOI: 10.1016/j.scib.2023.04.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 03/16/2023] [Accepted: 03/29/2023] [Indexed: 04/22/2023]
Affiliation(s)
- Ruyi Chen
- Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Feng Xu
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, China
| | - Qirui Cui
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing 210093, China; Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Jinghua Liang
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing 210093, China
| | - Yongjian Zhou
- Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Ning Wang
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, China
| | - Feng Pan
- Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Fei Xue
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, China; Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China.
| | - Hongxin Yang
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing 210093, China; Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China.
| | - Cheng Song
- Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China.
| |
Collapse
|
13
|
Chen Z, Turgut E, Jiang Y, Nguyen KX, Stolt MJ, Jin S, Ralph DC, Fuchs GD, Muller DA. Lorentz electron ptychography for imaging magnetic textures beyond the diffraction limit. NATURE NANOTECHNOLOGY 2022; 17:1165-1170. [PMID: 36316543 DOI: 10.1038/s41565-022-01224-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 09/05/2022] [Indexed: 06/16/2023]
Abstract
Nanoscale spin textures, especially magnetic skyrmions, have attracted intense interest as candidate high-density and power-efficient information carriers for spintronic devices1,2. Facilitating a deeper understanding of sub-hundred-nanometre to atomic-scale spin textures requires more advanced magnetic imaging techniques3-5. Here we demonstrate a Lorentz electron ptychography method that can enable high-resolution, high-sensitivity magnetic field imaging for widely available electron microscopes. The resolution of Lorentz electron ptychography is not limited by the usual diffraction limit of lens optics, but instead is determined by the maximum scattering angle at which a statistically meaningful dose can still be recorded-this can be an improvement of up to 2-6 times depending on the allowable dose. Using FeGe as the model system, we realize a more accurate magnetic field measurement of skyrmions with an improved spatial resolution and sensitivity by also correcting the probe-damping effect from the imaging optics via Lorentz electron ptychography. This allows us to directly resolve subtle internal structures of magnetic skyrmions near the skyrmion cores, boundaries and dislocations in an FeGe single crystal. Our study establishes a quantitative, high-resolution magnetic microscopy technique that can reveal nanoscale spin textures, especially magnetization discontinuities and topological defects in nanomagnets6. The technique's high-dose efficiency should also make it well suited for the exploration of magnetic textures in electron radiation-sensitive materials such as organic or molecular magnets7.
Collapse
Affiliation(s)
- Zhen Chen
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA.
- School of Materials Science and Engineering, Tsinghua University, Beijing, China.
| | - Emrah Turgut
- Department of Physics, Oklahoma State University, Stillwater, OK, USA
| | - Yi Jiang
- Advanced Photon Source, Argonne National Laboratory, Lemont, IL, USA
| | - Kayla X Nguyen
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA
| | - Matthew J Stolt
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Song Jin
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Daniel C Ralph
- Department of Physics, Cornell University, Ithaca, NY, USA
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY, USA
| | - Gregory D Fuchs
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA
| | - David A Muller
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA.
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY, USA.
| |
Collapse
|
14
|
Twitchett-Harrison AC, Loudon JC, Pepper RA, Birch MT, Fangohr H, Midgley PA, Balakrishnan G, Hatton PD. Confinement of Skyrmions in Nanoscale FeGe Device-like Structures. ACS APPLIED ELECTRONIC MATERIALS 2022; 4:4427-4437. [PMID: 36185075 PMCID: PMC9520970 DOI: 10.1021/acsaelm.2c00692] [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: 05/26/2022] [Accepted: 07/28/2022] [Indexed: 06/16/2023]
Abstract
Skyrmion-based devices have been proposed as a promising solution for low-energy data storage. These devices include racetrack or logic structures and require skyrmions to be confined in regions with dimensions comparable to the size of a single skyrmion. Here we examine skyrmions in FeGe device shapes using Lorentz transmission electron microscopy to reveal the consequences of skyrmion confinement in a device-like structure. Dumbbell-shaped elements were created by focused ion beam milling to provide regions where single skyrmions are confined adjacent to areas containing a skyrmion lattice. Simple block shapes of equivalent dimensions were also prepared to allow a direct comparison with skyrmion formation in a less complex, yet still confined, device geometry. The impact of applying a magnetic field and varying the temperature on the formation of skyrmions within the shapes was examined. This revealed that it is not just confinement within a small device structure that controls the position and number of skyrmions but that a complex device geometry changes the skyrmion behavior, including allowing skyrmions to form at lower applied magnetic fields than in simple shapes. The impact of edges in complex shapes is observed to be significant in changing the behavior of the magnetic textures formed. This could allow methods to be developed to control both the position and number of skyrmions within device structures.
Collapse
Affiliation(s)
- Alison C. Twitchett-Harrison
- Department
of Materials Science and Metallurgy, University
of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, United Kingdom
| | - James C. Loudon
- Department
of Materials Science and Metallurgy, University
of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, United Kingdom
| | - Ryan A. Pepper
- Faculty
of Engineering and Physical Sciences, University
of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Max T. Birch
- Max
Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
- Department
of Physics, Durham University, Durham DH1 3LE, United Kingdom
| | - Hans Fangohr
- Faculty
of Engineering and Physical Sciences, University
of Southampton, Southampton SO17 1BJ, United Kingdom
- Max
Planck Institute for Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Paul A. Midgley
- Department
of Materials Science and Metallurgy, University
of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, United Kingdom
| | - Geetha Balakrishnan
- Department
of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Peter D. Hatton
- Department
of Physics, Durham University, Durham DH1 3LE, United Kingdom
| |
Collapse
|
15
|
Wang K, Ren K, Cheng Y, Chen S, Zhang G. The impacts of molecular adsorption on antiferromagnetic MnPS 3 monolayers: enhanced magnetic anisotropy and intralayer Dzyaloshinskii-Moriya interaction. MATERIALS HORIZONS 2022; 9:2384-2392. [PMID: 35781317 DOI: 10.1039/d2mh00462c] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
In two-dimensional (2D) magnetic systems, significant magnetic anisotropy is required to protect magnetic ordering against thermal fluctuation. In this paper, we explored the effect of molecular adsorption on the magnetic anisotropy and intralayer Dzyaloshinskii-Moriya interaction (DMI) of monolayer MnPS3, combining the first-principles calculation and theoretical analysis. We find that molecular adsorption can break the spatial inversion symmetry in a 2D magnet, and results in a significant DMI, which is rare in pristine 2D magnets. For example, in an MPS-NO system, the magnitude of the asymmetric DMI vector increases 9 times, and the magnetocrystalline anisotropy increases 600 times compared with the pristine MPS monolayer. It is found the DMI mainly comes from the structural deformation after adsorption, whereas the increase of magnetocrystalline anisotropy mainly originates from a new 'bridge' super-exchange interaction between Mn ions and NO gas molecules. The calculated Mn-NO-Mn 'bridge' super-exchange coupling strength is much higher than the Mn-S-Mn coupling strength. Our findings offer a new strategy to increase the magnetic anisotropy and induce chiral magnetic structures in 2D magnets.
Collapse
Affiliation(s)
- Ke Wang
- School of Automation, Xi'an University of Posts & Telecommunications, Shaanxi, 710121, China
- Monash Suzhou Research Institute, Monash University, Suzhou Industrial Park, Suzhou 215000, P. R. China
| | - Kai Ren
- School of Mechanical and Electronic Engineering, Nanjing Forestry University, Nanjing, Jiangsu 210042, China
| | - Yuan Cheng
- Monash Suzhou Research Institute, Monash University, Suzhou Industrial Park, Suzhou 215000, P. R. China
- Department of Materials Science and Engineering, Monash University, VIC 3800, Australia
| | - Shuai Chen
- Institute of High Performance Computing, A*STAR, 138632, Singapore.
| | - Gang Zhang
- Institute of High Performance Computing, A*STAR, 138632, Singapore.
| |
Collapse
|
16
|
Takae K, Kawasaki T. Emergent elastic fields induced by topological phase transitions: Impact of molecular chirality and steric anisotropy. Proc Natl Acad Sci U S A 2022; 119:e2118492119. [PMID: 35344433 PMCID: PMC9168837 DOI: 10.1073/pnas.2118492119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 02/12/2022] [Indexed: 12/03/2022] Open
Abstract
SignificanceChirality, the property of an object that cannot be superimposed on its mirror image, plays an essential role in condensed matter, such as magnetic, electronic, and liquid crystal systems. Topological phases emerge in such chiral materials, wherein helical and vortex-like structures-called skyrmions-are observed. However, the role of elastic fields in these topological phases remains unexplored. Here, we construct a molecular model of two-dimensional crystals incorporating steric anisotropy and chiral interactions to elucidate this problem. The coupling between the elastic fields and phase transitions between uniform, helical, and half-skyrmion phases can be utilized to switch these topological phases by external forces. Our results provide a fundamental physical principle for designing topological materials using chiral molecular and colloidal crystals.
Collapse
Affiliation(s)
- Kyohei Takae
- Department of Fundamental Engineering, Institute of Industrial Science, University of Tokyo, Meguro-ku, Tokyo 153-8505, Japan
| | - Takeshi Kawasaki
- Department of Physics, Nagoya University, Nagoya 464-8602, Japan
| |
Collapse
|
17
|
Krizek F, Reimers S, Kašpar Z, Marmodoro A, Michalička J, Man O, Edström A, Amin OJ, Edmonds KW, Campion RP, Maccherozzi F, Dhesi SS, Zubáč J, Kriegner D, Carbone D, Železný J, Výborný K, Olejník K, Novák V, Rusz J, Idrobo JC, Wadley P, Jungwirth T. Atomically sharp domain walls in an antiferromagnet. SCIENCE ADVANCES 2022; 8:eabn3535. [PMID: 35353557 PMCID: PMC8967221 DOI: 10.1126/sciadv.abn3535] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Accepted: 02/07/2022] [Indexed: 06/14/2023]
Abstract
The interest in understanding scaling limits of magnetic textures such as domain walls spans the entire field of magnetism from its physical fundamentals to applications in information technologies. Here, we explore antiferromagnetic CuMnAs in which imaging by x-ray photoemission reveals the presence of magnetic textures down to nanoscale, reaching the detection limit of this established microscopy in antiferromagnets. We achieve atomic resolution by using differential phase-contrast imaging within aberration-corrected scanning transmission electron microscopy. We identify abrupt domain walls in the antiferromagnetic film corresponding to the Néel order reversal between two neighboring atomic planes. Our work stimulates research of magnetic textures at the ultimate atomic scale and sheds light on electrical and ultrafast optical antiferromagnetic devices with magnetic field-insensitive neuromorphic functionalities.
Collapse
Affiliation(s)
- Filip Krizek
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, 162 00 Praha 6, Czech Republic
| | - Sonka Reimers
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 ODE, UK
| | - Zdeněk Kašpar
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, 162 00 Praha 6, Czech Republic
- Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, 121 16 Prague 2, Czech Republic
| | - Alberto Marmodoro
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, 162 00 Praha 6, Czech Republic
| | - Jan Michalička
- Central European Institute of Technology, Brno University of Technology, Purkyňova 123, 612 00 Brno, Czech Republic
| | - Ondřej Man
- Central European Institute of Technology, Brno University of Technology, Purkyňova 123, 612 00 Brno, Czech Republic
| | - Alexander Edström
- Institut de Ciencia de Materials de Barcelona (ICMAB-CSIC), Campus UAB, 08193 Bellaterra, Spain
| | - Oliver J. Amin
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK
| | - Kevin W. Edmonds
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK
| | - Richard P. Campion
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK
| | - Francesco Maccherozzi
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 ODE, UK
| | - Samjeet S. Dhesi
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 ODE, UK
| | - Jan Zubáč
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, 162 00 Praha 6, Czech Republic
- Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, 121 16 Prague 2, Czech Republic
| | - Dominik Kriegner
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, 162 00 Praha 6, Czech Republic
- Institut für Festkörper- und Materialphysik, Technische Universität Dresden, 01062 Dresden, Germany
| | - Dina Carbone
- MAX IV Laboratory, Lund University, 22100 Lund, Sweden
| | - Jakub Železný
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, 162 00 Praha 6, Czech Republic
| | - Karel Výborný
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, 162 00 Praha 6, Czech Republic
| | - Kamil Olejník
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, 162 00 Praha 6, Czech Republic
| | - Vít Novák
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, 162 00 Praha 6, Czech Republic
| | - Jan Rusz
- Department of Physics and Astronomy, Uppsala University, Box 516, 75120 Uppsala, Sweden
| | - Juan-Carlos Idrobo
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Peter Wadley
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK
| | - Tomas Jungwirth
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, 162 00 Praha 6, Czech Republic
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK
| |
Collapse
|
18
|
Giant tunable spin Hall angle in sputtered Bi 2Se 3 controlled by an electric field. Nat Commun 2022; 13:1650. [PMID: 35347125 PMCID: PMC8960771 DOI: 10.1038/s41467-022-29281-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 02/23/2022] [Indexed: 11/21/2022] Open
Abstract
Finding an effective way to greatly tune spin Hall angle in a low power manner is of fundamental importance for tunable and energy-efficient spintronic devices. Recently, topological insulator of Bi2Se3, having a large intrinsic spin Hall angle, show great capability to generate strong current-induced spin-orbit torques. Here we demonstrate that the spin Hall angle in Bi2Se3 can be effectively tuned asymmetrically and even enhanced about 600% reversibly by applying a bipolar electric field across the piezoelectric substrate. We reveal that the enhancement of spin Hall angle originates from both the charge doping and piezoelectric strain effet on the spin Berry curvature near Fermi level in Bi2Se3. Our findings provide a platform for achieving low power consumption and tunable spintronic devices. Controlling the spin Hall angle is significant to tunable and energy-efficient spintronic devices. Here, the authors demonstrate that the spin Hall angle in Bi2Se3 can be tuned and even enhanced about 600% reversibly by the electric field.
Collapse
|
19
|
Jiang L, Huang C, Zhu Y, Pan Y, Fan J, Zhang K, Ma C, Shi D, Zhang H. Tuning the size of skyrmion by strain at the Co/Pt3 Interfaces. iScience 2022; 25:104039. [PMID: 35330683 PMCID: PMC8938285 DOI: 10.1016/j.isci.2022.104039] [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: 11/12/2021] [Revised: 02/09/2022] [Accepted: 03/03/2022] [Indexed: 11/25/2022] Open
Abstract
Based on density functional theory calculations, we elucidated the tunability of the atomic structures and magnetic interactions of Co/Pt3 interface (one layer of hcp(0001) Co and three layers of fcc(111) Pt) and thus the skyrmion sizes using strain. The dispersion relations of the spin spiral in the opposite directions, E(q) and E(-q), were evaluated based on generalized Bloch equations. Effective exchange coupling (EC) and Dzyaloshinsky-Moriya interaction (DMI) parameters between different neighbors Ji and di at different lattice constants were derived by fitting the resulting spin spiral dispersion E(q) to EC model with DMI and E(q)-E(-q) formula, respectively. We observed an increase in DMI and a significant decrease in EC with an increase in strain. Hence, the size of Néel-type skyrmions determined by the ratio of EC/DMI can be controlled by applying strain, leading to an effective approach to tailor the formation of skyrmion lattices by inducing slight structural modifications on the magnetic thin films. Calculate the EC and DMI of multi-nearest neighbors in the VASP program Show detailed changes of multi-nearest neighboring EC and DMI with deformation The size of skyrmion does decrease as the lattice constant increases Distance between Co and Pt layer determines the size of DMI
Collapse
|
20
|
Karube K, Peng L, Masell J, Hemmida M, Krug von Nidda HA, Kézsmárki I, Yu X, Tokura Y, Taguchi Y. Doping Control of Magnetic Anisotropy for Stable Antiskyrmion Formation in Schreibersite (Fe,Ni) 3 P with S 4 symmetry. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2108770. [PMID: 35032408 DOI: 10.1002/adma.202108770] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 01/06/2022] [Indexed: 06/14/2023]
Abstract
Magnetic skyrmions, vortex-like topological spin textures, have attracted much interest in a wide range of research fields from fundamental physics to spintronics applications. Recently, growing attention is also paid to antiskyrmions emerging with opposite topological charge in non-centrosymmetric magnets with D2d or S4 symmetry. In these magnets, complex interplay among anisotropic Dzyaloshinskii-Moriya interaction, uniaxial magnetic anisotropy, and magnetic dipolar interactions generates various magnetic textures. However, the precise role of these magnetic interactions in stabilizing antiskyrmions remains to be elucidated. In this work, the uniaxial magnetic anisotropy of schreibersite (Fe,Ni)3 P with S4 symmetry is controlled by doping and its impact on the stability of antiskyrmions is investigated. The authors' magnetometry study, supported by ferromagnetic resonance spectroscopy, shows that the variation of the Ni content and slight doping with 4d transition metals considerably change the magnetic anisotropy. In particular, doping with Pd induces easy-axis anisotropy, giving rise to formation of antiskyrmions, while a temperature-induced spin reorientation is observed in an Rh-doped compound. In combination with Lorentz transmission electron microscopy and micromagnetic simulations, the stability of antiskyrmion as functions of uniaxial anisotropy and demagnetization energy is quantitatively analyzed, and demonstrated that subtle balance between them is necessary to stabilize the antiskyrmions.
Collapse
Affiliation(s)
- Kosuke Karube
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
| | - Licong Peng
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
| | - Jan Masell
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
- Institute of Theoretical Solid State Physics, Karlsruhe Institute of Technology (KIT), Karlsruhe, 76049, Germany
| | - Mamoun Hemmida
- Experimental Physics V, University of Augsburg, Augsburg, 86135, Germany
| | | | - István Kézsmárki
- Experimental Physics V, University of Augsburg, Augsburg, 86135, Germany
| | - Xiuzhen Yu
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
| | - Yoshinori Tokura
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
- Department of Applied Physics, University of Tokyo, Bunkyo-ku, 113-8656, Japan
- Tokyo College, University of Tokyo, Bunkyo-ku, 113-8656, Japan
| | - Yasujiro Taguchi
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
| |
Collapse
|
21
|
Zhang Y, Liu J, Dong Y, Wu S, Zhang J, Wang J, Lu J, Rückriegel A, Wang H, Duine R, Yu H, Luo Z, Shen K, Zhang J. Strain-Driven Dzyaloshinskii-Moriya Interaction for Room-Temperature Magnetic Skyrmions. PHYSICAL REVIEW LETTERS 2021; 127:117204. [PMID: 34558947 DOI: 10.1103/physrevlett.127.117204] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 08/12/2021] [Accepted: 08/13/2021] [Indexed: 06/13/2023]
Abstract
Dzyaloshinskii-Moriya interaction in magnets, which is usually derived from inversion symmetry breaking at interfaces or in noncentrosymmetric crystals, plays a vital role in chiral spintronics. Here we report that an emergent Dzyaloshinskii-Moriya interaction can be achieved in a centrosymmetric material, La_{0.67}Sr_{0.33}MnO_{3}, by a graded strain. This strain-driven Dzyaloshinskii-Moriya interaction not only exhibits distinctive two coexisting nonreciprocities of spin-wave propagation in one system, but also brings about a robust room-temperature magnetic skyrmion lattice as well as a spiral lattice at zero magnetic field. Our results demonstrate the feasibility of investigating chiral spintronics in a large category of centrosymmetric magnetic materials.
Collapse
Affiliation(s)
- Yuelin Zhang
- Department of Physics, Beijing Normal University, Beijing 100875, China
| | - Jie Liu
- Department of Physics, Beijing Normal University, Beijing 100875, China
- The Center for Advanced Quantum Studies, Beijing Normal University, Beijing 100191, China
| | - Yongqi Dong
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Shizhe Wu
- Department of Physics, Beijing Normal University, Beijing 100875, China
| | - Jianyu Zhang
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, China
| | - Jie Wang
- Department of Physics, Beijing Normal University, Beijing 100875, China
| | - Jingdi Lu
- Department of Physics, Beijing Normal University, Beijing 100875, China
| | - Andreas Rückriegel
- Institute for Theoretical Physics and Center for Extreme Matter and Emergent Phenomena, Utrecht University, Leuvenlaan 4, 3584 CE Utrecht, Netherlands
- Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, Netherlands
| | - Hanchen Wang
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, China
| | - Rembert Duine
- Institute for Theoretical Physics and Center for Extreme Matter and Emergent Phenomena, Utrecht University, Leuvenlaan 4, 3584 CE Utrecht, Netherlands
- Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, Netherlands
| | - Haiming Yu
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, China
| | - Zhenlin Luo
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Ka Shen
- Department of Physics, Beijing Normal University, Beijing 100875, China
- The Center for Advanced Quantum Studies, Beijing Normal University, Beijing 100191, China
| | - Jinxing Zhang
- Department of Physics, Beijing Normal University, Beijing 100875, China
| |
Collapse
|
22
|
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.
Collapse
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
| |
Collapse
|
23
|
Shimojima T, Nakamura A, Yu X, Karube K, Taguchi Y, Tokura Y, Ishizaka K. Nano-to-micro spatiotemporal imaging of magnetic skyrmion's life cycle. SCIENCE ADVANCES 2021; 7:7/25/eabg1322. [PMID: 34134977 PMCID: PMC8208720 DOI: 10.1126/sciadv.abg1322] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Accepted: 04/30/2021] [Indexed: 05/27/2023]
Abstract
Magnetic skyrmions are self-organized topological spin textures that behave like particles. Because of their fast creation and typically long lifetime, experimental verification of skyrmion's creation/annihilation processes has been challenging. Here, we successfully track skyrmion dynamics in defect-introduced Co9Zn9Mn2 by using pump-probe Lorentz transmission electron microscope. Following the nanosecond photothermal excitation, we resolve 160-nm skyrmion's proliferation at <1 ns, contraction at 5 ns, drift from 10 ns to 4 μs, and coalescence at ~5 μs. These motions relay the multiscale arrangement and relaxation of skyrmion clusters in a repeatable cycle of 20 kHz. Such repeatable dynamics of skyrmions, arising from the weakened but still persistent topological protection around defects, enables us to visualize the whole life of the skyrmions and demonstrates the possible high-frequency manipulations of topological charges brought by skyrmions.
Collapse
Affiliation(s)
| | - Asuka Nakamura
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - Xiuzhen Yu
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - Kosuke Karube
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - Yasujiro Taguchi
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - Yoshinori Tokura
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
- Quantum-Phase Electronics Center (QPEC) and Department of Applied Physics, The University of Tokyo, Tokyo 113-8656, Japan
- Tokyo College, The University of Tokyo, Tokyo 113-8656, Japan
| | - Kyoko Ishizaka
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
- Quantum-Phase Electronics Center (QPEC) and Department of Applied Physics, The University of Tokyo, Tokyo 113-8656, Japan
| |
Collapse
|
24
|
Abstract
Skyrmion, a concept originally proposed in particle physics half a century ago, can now find the most fertile field for its applicability, that is, the magnetic skyrmion realized in helimagnetic materials. The spin swirling vortex-like texture of the magnetic skyrmion can define the particle nature by topology; that is, all the constituent spin moments within the two-dimensional sheet wrap the sphere just one time. Such a topological nature of the magnetic skyrmion can lead to extraordinary metastability via topological protection and the driven motion with low electric-current excitation, which may promise future application to spintronics. The skyrmions in the magnetic materials frequently show up as the crystal lattice form, e.g., hexagonal lattice, but sometimes as isolated or independent particles. These skyrmions in magnets were initially found in acentric magnets, such as chiral, polar, and bilayered magnets endowed with antisymmetric spin exchange interaction, while the skyrmion host materials have been explored in a broader family of compounds including centrosymmetric magnets. This review describes the materials science and materials chemistry of magnetic skyrmions using the classification scheme of the skyrmion forming microscopic mechanisms. The emergent phenomena and functions mediated by skyrmions are described, including the generation of emergent magnetic and electric field by statics and dynamics of skrymions and the inherent magnetoelectric effect. The other important magnetic topological defects in two or three dimensions, such as biskyrmions, antiskyrmions, merons, and hedgehogs, are also reviewed in light of their interplay with the skyrmions.
Collapse
Affiliation(s)
- Yoshinori Tokura
- Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan.,RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan.,Tokyo College, University of Tokyo, Tokyo 113-8656, Japan
| | - Naoya Kanazawa
- Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan
| |
Collapse
|
25
|
Cui B, Yu D, Shao Z, Liu Y, Wu H, Nan P, Zhu Z, Wu C, Guo T, Chen P, Zhou HA, Xi L, Jiang W, Wang H, Liang S, Du H, Wang KL, Wang W, Wu K, Han X, Zhang G, Yang H, Yu G. Néel-Type Elliptical Skyrmions in a Laterally Asymmetric Magnetic Multilayer. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2006924. [PMID: 33599001 DOI: 10.1002/adma.202006924] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 01/10/2021] [Indexed: 06/12/2023]
Abstract
Magnetic skyrmions, topological-chiral spin textures, have potential applications in next-generation high-density and energy-efficient spintronic devices for information storage and logic technologies. Tailoring the detailed spin textures of skyrmions is of pivotal importance for tuning skyrmion dynamics, which is one of the key factors for the design of skyrmionic devices. Here, the direct observation of parallel aligned elliptical magnetic skyrmions in Pt/Co/Ta multilayers with an oblique-angle deposited Co layer is reported. Domain wall velocity and spin-orbit-torque-induced out-of-plane effective field analysis demonstrate that the formation of unusual elliptical skyrmions is correlated to the anisotropic effective perpendicular magnetic anisotropy energy density (Keff u ) and Dzyaloshinskii-Moriya interaction (DMI) in the film plane. Structural analysis and first-principles calculations further show that the anisotropic Keff u and DMI originate from the interfacial anisotropic strain introduced by the oblique-angle deposition. The work provides a method to tune the spin textures of skyrmions in magnetic multilayers and, thereby, a new degree of freedom for the design of skyrmionic devices.
Collapse
Affiliation(s)
- Baoshan Cui
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Dongxing Yu
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China
| | - Ziji Shao
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China
| | - Yizhou Liu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
| | - Hao Wu
- Department of Electrical and Computer Engineering, University of California, Los Angeles, CA, 90095, USA
| | - Pengfei Nan
- Institutes of Physical Science and Information Technology, Anhui University, Hefei, 230601, China
| | - Zengtai Zhu
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Chuangwen Wu
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
- Faculty of Physics and Electronic Science, Hubei University, Wuhan, 430062, China
| | - Tengyu Guo
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Peng Chen
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Heng-An Zhou
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, 100084, China
| | - Li Xi
- Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, School of Physical Science and Technology, Lanzhou University, Lanzhou, 730000, China
| | - Wanjun Jiang
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, 100084, China
| | - Hao Wang
- Faculty of Physics and Electronic Science, Hubei University, Wuhan, 430062, China
| | - Shiheng Liang
- Faculty of Physics and Electronic Science, Hubei University, Wuhan, 430062, China
| | - Haifeng Du
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory of Chinese Academy of Sciences, University of Science and Technology of China, Hefei, 230031, China
| | - Kang L Wang
- Department of Electrical and Computer Engineering, University of California, Los Angeles, CA, 90095, USA
| | - Wenhong Wang
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Kehui Wu
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Xiufeng Han
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Guangyu Zhang
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Hongxin Yang
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China
| | - Guoqiang Yu
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| |
Collapse
|
26
|
Ba Y, Zhuang S, Zhang Y, Wang Y, Gao Y, Zhou H, Chen M, Sun W, Liu Q, Chai G, Ma J, Zhang Y, Tian H, Du H, Jiang W, Nan C, Hu JM, Zhao Y. Electric-field control of skyrmions in multiferroic heterostructure via magnetoelectric coupling. Nat Commun 2021; 12:322. [PMID: 33436572 PMCID: PMC7803786 DOI: 10.1038/s41467-020-20528-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 11/30/2020] [Indexed: 11/09/2022] Open
Abstract
Room-temperature skyrmions in magnetic multilayers are considered to be promising candidates for the next-generation spintronic devices. Several approaches have been developed to control skyrmions, but they either cause significant heat dissipation or require ultrahigh electric fields near the breakdown threshold. Here, we demonstrate electric-field control of skyrmions through strain-mediated magnetoelectric coupling in ferromagnetic/ferroelectric multiferroic heterostructures. We show the process of non-volatile creation of multiple skyrmions, reversible deformation and annihilation of a single skyrmion by performing magnetic force microscopy with in situ electric fields. Strain-induced changes in perpendicular magnetic anisotropy and interfacial Dzyaloshinskii–Moriya interaction strength are characterized experimentally. These experimental results, together with micromagnetic simulations, demonstrate that strain-mediated magnetoelectric coupling (via strain-induced changes in both the perpendicular magnetic anisotropy and interfacial Dzyaloshinskii–Moriya interaction is responsible for the observed electric-field control of skyrmions. Our work provides a platform to investigate electric-field control of skyrmions in multiferroic heterostructures and paves the way towards more energy-efficient skyrmion-based spintronics. The common approaches to control of skymions cause significant heat dissipation or require high electric fields near the breakdown threshold. Here, the authors demonstrate electric-field control of skyrmions through strain-mediated magnetoelectric coupling in multiferroic heterostructures.
Collapse
Affiliation(s)
- You Ba
- Department of Physics, State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing, 100084, China.,Frontier Science Center for Quantum Information, Tsinghua University, Beijing, 100084, China
| | - Shihao Zhuang
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Yike Zhang
- Department of Physics, State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing, 100084, China.,Frontier Science Center for Quantum Information, Tsinghua University, Beijing, 100084, China
| | - Yutong Wang
- Department of Physics, State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing, 100084, China.,Frontier Science Center for Quantum Information, Tsinghua University, Beijing, 100084, China
| | - Yang Gao
- Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou, 730000, China
| | - Hengan Zhou
- Department of Physics, State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing, 100084, China.,Frontier Science Center for Quantum Information, Tsinghua University, Beijing, 100084, China
| | - Mingfeng Chen
- School of Materials Science and Engineering, State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, Beijing, 100084, China
| | - Weideng Sun
- Department of Physics, State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing, 100084, China.,Frontier Science Center for Quantum Information, Tsinghua University, Beijing, 100084, China
| | - Quan Liu
- Department of Physics, State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing, 100084, China.,Frontier Science Center for Quantum Information, Tsinghua University, Beijing, 100084, China
| | - Guozhi Chai
- Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou, 730000, China
| | - Jing Ma
- School of Materials Science and Engineering, State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, Beijing, 100084, China
| | - Ying Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Huanfang Tian
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Haifeng Du
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory of Chinese Academy of Sciences, University of Science and Technology of China, Hefei, 230031, China
| | - Wanjun Jiang
- Department of Physics, State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing, 100084, China.,Frontier Science Center for Quantum Information, Tsinghua University, Beijing, 100084, China
| | - Cewen Nan
- School of Materials Science and Engineering, State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, Beijing, 100084, China
| | - Jia-Mian Hu
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA.
| | - Yonggang Zhao
- Department of Physics, State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing, 100084, China. .,Frontier Science Center for Quantum Information, Tsinghua University, Beijing, 100084, China.
| |
Collapse
|
27
|
Rózsa L, Weißenhofer M, Nowak U. Spin waves in skyrmionic structures with various topological charges. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 33:054001. [PMID: 33091880 DOI: 10.1088/1361-648x/abc404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 10/22/2020] [Indexed: 06/11/2023]
Abstract
Equilibrium properties and localized magnon excitations are investigated in topologically distinct skyrmionic textures. The observed shape of the structures and their orientation on the lattice is explained based on their vorticities and the symmetry of the crystal. The transformation between different textures and their annihilation as a function of magnetic field is understood based on the energy differences between them. The angular momentum spin-wave eigenmodes characteristic of cylindrically symmetric structures are combined in the distorted spin configurations, leading to avoided crossings in the magnon spectrum. The susceptibility of the skyrmionic textures to homogeneous external fields is calculated, revealing that a high number of modes become detectable due to the hybridization between the angular momentum eigenmodes. These findings should contribute to the observation of spin waves in distorted skyrmionic structures via experiments and numerical simulations, widening the range of their possible applications in magnonic devices.
Collapse
Affiliation(s)
- Levente Rózsa
- Department of Physics, University of Konstanz, D-78457 Konstanz, Germany
| | - Markus Weißenhofer
- Department of Physics, University of Konstanz, D-78457 Konstanz, Germany
| | - Ulrich Nowak
- Department of Physics, University of Konstanz, D-78457 Konstanz, Germany
| |
Collapse
|
28
|
Deterministic reversal of single magnetic vortex circulation by an electric field. Sci Bull (Beijing) 2020; 65:1260-1267. [PMID: 36747413 DOI: 10.1016/j.scib.2020.04.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 02/23/2020] [Accepted: 03/27/2020] [Indexed: 02/08/2023]
Abstract
The ability to control magnetic vortex is critical for their potential applications in spintronic devices. Traditional methods including magnetic field, spin-polarized current etc. have been used to flip the core and/or reverse circulation of vortex. However, it is challenging for deterministic electric-field control of the single magnetic vortex textures with time-reversal broken symmetry and no planar magnetic anisotropy. Here it is reported that a deterministic reversal of single magnetic vortex circulation can be driven back and forth by a space-varying strain in multiferroic heterostructures, which is controlled by using a bi-axial pulsed electric field. Phase-field simulation reveals the mechanism of the emerging magnetoelastic energy with the space variation and visualizes the reversal pathway of the vortex. This deterministic electric-field control of the single magnetic vortex textures demonstrates a new approach to integrate the low-dimensional spin texture into the magnetoelectric thin film devices with low energy consumption.
Collapse
|
29
|
Wang Y, Wang L, Xia J, Lai Z, Tian G, Zhang X, Hou Z, Gao X, Mi W, Feng C, Zeng M, Zhou G, Yu G, Wu G, Zhou Y, Wang W, Zhang XX, Liu J. Electric-field-driven non-volatile multi-state switching of individual skyrmions in a multiferroic heterostructure. Nat Commun 2020; 11:3577. [PMID: 32681004 PMCID: PMC7367868 DOI: 10.1038/s41467-020-17354-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Accepted: 06/26/2020] [Indexed: 11/09/2022] Open
Abstract
Electrical manipulation of skyrmions attracts considerable attention for its rich physics and promising applications. To date, such a manipulation is realized mainly via spin-polarized current based on spin-transfer torque or spin-orbital torque effect. However, this scheme is energy consuming and may produce massive Joule heating. To reduce energy dissipation and risk of heightened temperatures of skyrmion-based devices, an effective solution is to use electric field instead of current as stimulus. Here, we realize an electric-field manipulation of skyrmions in a nanostructured ferromagnetic/ferroelectrical heterostructure at room temperature via an inverse magneto-mechanical effect. Intriguingly, such a manipulation is non-volatile and exhibits a multistate feature. Numerical simulations indicate that the electric-field manipulation of skyrmions originates from strain-mediated modification of effective magnetic anisotropy and Dzyaloshinskii-Moriya interaction. Our results open a direction for constructing low-energy-dissipation, non-volatile, and multistate skyrmion-based spintronic devices.
Collapse
Affiliation(s)
- Yadong Wang
- 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, China
- National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou, 510006, China
| | - Lei Wang
- School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Jing Xia
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, Guangdong, 518172, China
| | - Zhengxun Lai
- Colleage of Science, Tianjin University, Tianjin, 300392, China
| | - Guo Tian
- 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, China
- National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou, 510006, China
| | - Xichao Zhang
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, Guangdong, 518172, 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, China.
- National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou, 510006, China.
| | - 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, China.
- National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou, 510006, China.
| | - Wenbo Mi
- Colleage of Science, Tianjin University, Tianjin, 300392, China
| | - Chun Feng
- School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, 100083, China.
| | - Min Zeng
- 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, China
- National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou, 510006, China
| | - Guofu Zhou
- 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, China
- National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou, 510006, China
| | - Guanghua Yu
- School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Guangheng Wu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Yan Zhou
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, Guangdong, 518172, China
| | - Wenhong Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Xi-Xiang Zhang
- Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
| | - Junming Liu
- Laboratory of Solid State Microstructures and Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 211102, China
| |
Collapse
|
30
|
Filianina M, Hanke JP, Lee K, Han DS, Jaiswal S, Rajan A, Jakob G, Mokrousov Y, Kläui M. Electric-Field Control of Spin-Orbit Torques in Perpendicularly Magnetized W/CoFeB/MgO Films. PHYSICAL REVIEW LETTERS 2020; 124:217701. [PMID: 32530662 DOI: 10.1103/physrevlett.124.217701] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 04/03/2020] [Accepted: 04/29/2020] [Indexed: 06/11/2023]
Abstract
Controlling magnetism by electric fields offers a highly attractive perspective for designing future generations of energy-efficient information technologies. Here, we demonstrate that the magnitude of current-induced spin-orbit torques in thin perpendicularly magnetized CoFeB films can be tuned and even increased by electric-field generated piezoelectric strain. Using theoretical calculations, we uncover that the subtle interplay of spin-orbit coupling, crystal symmetry, and orbital polarization is at the core of the observed strain dependence of spin-orbit torques. Our results open a path to integrating two energy efficient spin manipulation approaches, the electric-field-induced strain and the current-induced magnetization switching, thereby enabling novel device concepts.
Collapse
Affiliation(s)
- Mariia Filianina
- Institute of Physics, Johannes Gutenberg University, 55099 Mainz, Germany
- Graduate School of Excellence Material Science in Mainz, 55099 Mainz, Germany
| | - Jan-Philipp Hanke
- Institute of Physics, Johannes Gutenberg University, 55099 Mainz, Germany
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany
| | - Kyujoon Lee
- Institute of Physics, Johannes Gutenberg University, 55099 Mainz, Germany
| | - Dong-Soo Han
- Institute of Physics, Johannes Gutenberg University, 55099 Mainz, Germany
- Center for Spintronics, Korea Institute for Science and Technology, 02792 Seoul, Republic of Korea
| | - Samridh Jaiswal
- Institute of Physics, Johannes Gutenberg University, 55099 Mainz, Germany
- Singulus Technology AG, 63796 Kahl am Main, Germany
| | - Adithya Rajan
- Institute of Physics, Johannes Gutenberg University, 55099 Mainz, Germany
| | - Gerhard Jakob
- Institute of Physics, Johannes Gutenberg University, 55099 Mainz, Germany
- Graduate School of Excellence Material Science in Mainz, 55099 Mainz, Germany
| | - Yuriy Mokrousov
- Institute of Physics, Johannes Gutenberg University, 55099 Mainz, Germany
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany
| | - Mathias Kläui
- Institute of Physics, Johannes Gutenberg University, 55099 Mainz, Germany
- Graduate School of Excellence Material Science in Mainz, 55099 Mainz, Germany
| |
Collapse
|
31
|
Gusev NS, Sadovnikov AV, Nikitov SA, Sapozhnikov MV, Udalov OG. Manipulation of the Dzyaloshinskii-Moriya Interaction in Co/Pt Multilayers with Strain. PHYSICAL REVIEW LETTERS 2020; 124:157202. [PMID: 32357040 DOI: 10.1103/physrevlett.124.157202] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 01/09/2020] [Accepted: 03/20/2020] [Indexed: 06/11/2023]
Abstract
Interfacial Dzyaloshinskii-Moriya interaction (DMI) is experimentally investigated in Pt/Co/Pt multilayer films under strain. A strong variation (from 0.1 to 0.8 mJ/m^{2}) of the DMI constant is demonstrated at ±0.1% in-plane uniaxial deformation of the films. The anisotropic strain induces strong DMI anisotropy. The DMI constant perpendicular to the strain direction changes sign, while the constant along the strain direction does not. Estimates show that the DMI can be controlled with an electric field in hybrid ferroelectric-ferromagnetic systems. So, the observed effect opens the way to control the DMI and eventually skyrmions with a voltage via a strain-mediated magnetoelectric coupling.
Collapse
Affiliation(s)
- N S Gusev
- Institute for Physics of Microstructures RAS, Nizhny Novgorod 603950, Russia
| | - A V Sadovnikov
- Saratov State University, Saratov 410012, Russia
- Kotelnikov Institute of Radioengineering and Electronics RAS, Moscow, 125009, Russia
| | - S A Nikitov
- Saratov State University, Saratov 410012, Russia
- Kotelnikov Institute of Radioengineering and Electronics RAS, Moscow, 125009, Russia
| | - M V Sapozhnikov
- Institute for Physics of Microstructures RAS, Nizhny Novgorod 603950, Russia
- Lobachevsky State University of Nizhny Novgorod, 603950 Nizhny Novgorod, Russia
| | - O G Udalov
- Institute for Physics of Microstructures RAS, Nizhny Novgorod 603950, Russia
- Lobachevsky State University of Nizhny Novgorod, 603950 Nizhny Novgorod, Russia
- Department of Physics and Astronomy, California State University Northridge, Northridge, California 91330, USA
| |
Collapse
|
32
|
Jena J, Göbel B, Ma T, Kumar V, Saha R, Mertig I, Felser C, Parkin SSP. Elliptical Bloch skyrmion chiral twins in an antiskyrmion system. Nat Commun 2020; 11:1115. [PMID: 32111842 PMCID: PMC7048809 DOI: 10.1038/s41467-020-14925-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 02/12/2020] [Indexed: 11/22/2022] Open
Abstract
Skyrmions and antiskyrmions are distinct topological chiral spin textures that have been observed in various material systems depending on the symmetry of the crystal structure. Here we show, using Lorentz transmission electron microscopy, that arrays of skyrmions can be stabilized in a tetragonal inverse Heusler with D2d symmetry whose Dzyaloshinskii-Moriya interaction (DMI) otherwise supports antiskyrmions. These skyrmions can be distinguished from those previously found in several B20 systems which have only one chirality and are circular in shape. We find Bloch-type elliptical skyrmions with opposite chiralities whose major axis is oriented along two specific crystal directions: [010] and [100]. These structures are metastable over a wide temperature range and we show that they are stabilized by long-range dipole-dipole interactions. The possibility of forming two distinct chiral spin textures with opposite topological charges of ±1 in one material makes the family of D2d materials exceptional. Skyrmions and anti-skyrmions often exist in distinct material systems. Here, the authors observe elliptical skyrmions and anti-skyrmions with opposite topological charges in one tetragonal Heusler compound Mn1.4Pt0.9Pd0.1Sn with D2d symmetry.
Collapse
Affiliation(s)
- Jagannath Jena
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120, Halle (Saale), Germany
| | - Börge Göbel
- 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
| | - Vivek Kumar
- 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
| | - Ingrid Mertig
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120, Halle (Saale), Germany.,Institute of Physics, Martin Luther University Halle-Wittenberg, 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.
| |
Collapse
|
33
|
Nomura T, Zhang XX, Zherlitsyn S, Wosnitza J, Tokura Y, Nagaosa N, Seki S. Phonon Magnetochiral Effect. PHYSICAL REVIEW LETTERS 2019; 122:145901. [PMID: 31050445 DOI: 10.1103/physrevlett.122.145901] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Indexed: 06/09/2023]
Abstract
The magnetochiral effect (MCE) of phonons, a nonreciprocal acoustic propagation arising due to symmetry principles, is demonstrated in the chiral-lattice ferrimagnet Cu_{2}OSeO_{3}. Our high-resolution ultrasound experiments reveal that the sound velocity differs for parallel and antiparallel propagation with respect to the external magnetic field. The sign of the nonreciprocity depends on the chirality of the crystal in accordance with the selection rule of the MCE. The nonreciprocity is enhanced below the magnetic ordering temperature and at higher ultrasound frequencies, which is quantitatively explained by a proposed magnon-phonon hybridization mechanism.
Collapse
Affiliation(s)
- T Nomura
- Hochfeld-Magnetlabor Dresden (HLD-EMFL), Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
| | - X-X Zhang
- Department of Applied Physics, The University of Tokyo, Tokyo 113-8656, Japan
- Quantum Matter Institute, University of British Columbia, Vancouver BC V6T 1Z4, Canada
| | - S Zherlitsyn
- Hochfeld-Magnetlabor Dresden (HLD-EMFL), Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
| | - J Wosnitza
- Hochfeld-Magnetlabor Dresden (HLD-EMFL), Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
- Institut für Festkörper-und Materialphysik, TU-Dresden, 01062 Dresden, Germany
| | - Y Tokura
- Department of Applied Physics, The University of Tokyo, Tokyo 113-8656, Japan
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - N Nagaosa
- Department of Applied Physics, The University of Tokyo, Tokyo 113-8656, Japan
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - S Seki
- Department of Applied Physics, The University of Tokyo, Tokyo 113-8656, Japan
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
- Institute of Engineering Innovation, The University of Tokyo, Tokyo 113-8656, Japan
| |
Collapse
|
34
|
Morvan FJ, Luo HB, Yang HX, Zhang X, Zhou Y, Zhao GP, Xia WX, Liu JP. An achiral ferromagnetic/chiral antiferromagnetic bilayer system leading to controllable size and density of skyrmions. Sci Rep 2019; 9:2970. [PMID: 30814603 PMCID: PMC6393523 DOI: 10.1038/s41598-019-39675-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 01/18/2019] [Indexed: 11/22/2022] Open
Abstract
Magnetic skyrmions are topologically protected domain structures related to the Dzyaloshinskii-Moriya interaction (DMI). To understand how magnetic skyrmions occur under different circumstances, we propose a model for skyrmion formation in a bilayer system of ferromagnetic/antiferromagnetic (FM/AFM) films, in which the bulk DMI is only present in the AFM film. Micromagnetic simulations reveal that skyrmions are formed in this system due to the competition between the DMI and demagnetization energies. A critical interfacial exchange energy (Ai = 6.5 mJ/m2) is determined, above which the competition occurs at its full extent. More skyrmions are formed with increasing external magnetic field till a critical value above which the external field is too large and thus leading to the annihilation of skyrmions. The spacing between two skyrmions can be as small as 45 nm. Our results may give technological implications for future skyrmion applications.
Collapse
Affiliation(s)
- F J Morvan
- CAS Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China.,Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China.,University of Chinese Academy of Sciences, 19A Yuquan Rd, Shijingshan District, Beijing, 100049, China
| | - H B Luo
- CAS Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China. .,Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China.
| | - H X Yang
- CAS Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China.,Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China
| | - X Zhang
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, Guangdong, 518172, China
| | - Y Zhou
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, Guangdong, 518172, China
| | - G P Zhao
- College of Physics and Electronic Engineering, Sichuan Normal University, Chengdu, 610068, China
| | - W X Xia
- CAS Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China.,Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China
| | - J P Liu
- CAS Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China. .,Department of Physics, University of Texas at Arlington, Arlington, TX, 76019, USA.
| |
Collapse
|
35
|
Yu XZ, Koshibae W, Tokunaga Y, Shibata K, Taguchi Y, Nagaosa N, Tokura Y. Transformation between meron and skyrmion topological spin textures in a chiral magnet. Nature 2018; 564:95-98. [DOI: 10.1038/s41586-018-0745-3] [Citation(s) in RCA: 183] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 10/11/2018] [Indexed: 11/09/2022]
|
36
|
Adams T, Garst M, Bauer A, Georgii R, Pfleiderer C. Response of the Skyrmion Lattice in MnSi to Cubic Magnetocrystalline Anisotropies. PHYSICAL REVIEW LETTERS 2018; 121:187205. [PMID: 30444411 DOI: 10.1103/physrevlett.121.187205] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 10/05/2018] [Indexed: 06/09/2023]
Abstract
We report high-precision small-angle neutron scattering of the orientation of the Skyrmion lattice in a spherical sample of MnSi under systematic changes of the magnetic field direction. For all field directions the Skyrmion lattice may be accurately described as a triple-Q[over →] state, where the modulus |Q[over →]| is constant and the wave vectors enclose rigid angles of 120°. Along a great circle across ⟨100⟩, ⟨110⟩, and ⟨111⟩ the normal to the Skyrmion-lattice plane varies systematically by ±3° with respect to the field direction, while the in-plane alignment displays a reorientation by 15° for magnetic field along ⟨100⟩. Our observations are qualitatively and quantitatively in excellent agreement with an effective potential, which is determined by the symmetries of the tetrahedral point group T and includes contributions up to sixth order in spin-orbit coupling, providing a full account of the effect of cubic magnetocrystalline anisotropies on the Skyrmion lattice in MnSi.
Collapse
Affiliation(s)
- T Adams
- Physik Department, Technische Universität München, D-85748 Garching, Germany
| | - M Garst
- Institute for Theoretical Physics, Universität zu Köln, D-50937 Köln, Germany
- Institut für Theoretische Physik, Technische Universität Dresden, 01062 Dresden, Germany
| | - A Bauer
- Physik Department, Technische Universität München, D-85748 Garching, Germany
| | - R Georgii
- Physik Department, Technische Universität München, D-85748 Garching, Germany
- Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, D-85747 Garching, Germany
| | - C Pfleiderer
- Physik Department, Technische Universität München, D-85748 Garching, Germany
| |
Collapse
|
37
|
Wan X, Hu Y, Wang B. Tunable surface configuration of skyrmion lattices in cubic helimagnets. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:245001. [PMID: 29726846 DOI: 10.1088/1361-648x/aac288] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In bulk helimagnets, the presence of magnetic skyrmion lattices is always accompanied by a periodic stress field due to the intrinsic magnetoelastic coupling. The release of this nontrivial stress field at the surface causes a periodic displacement field, which characterizes a novel particle-like property of skyrmion: its surface configuration. Here, we derive the analytical solution of this displacement field for semi-infinite cubic helimagnet with the skyrmion magnetization approximated by the triple-Q representation. For MnSi, we show that the skyrmion lattices have a bumpy surface configuration characterized by periodically arranged peaks with a characteristic height of about 10-13 m. The pattern of the peaks can be controlled by varying the strength of the applied magnetic field. Moreover, we prove that the surface configuration varies together with the motion and deformation of the skyrmion lattices. As a result, the surface configuration can be tuned by application of electric current, mechanical loads, as well as any other effective external fields for skyrmion lattices.
Collapse
Affiliation(s)
- Xuejin Wan
- Sino-French Institute of Nuclear Engineering and Technology, Sun Yat-sen University, 510275 Guangzhou, People's Republic of China
| | | | | |
Collapse
|
38
|
Hou Z, Zhang Q, Xu G, Gong C, Ding B, Wang Y, Li H, Liu E, Xu F, Zhang H, Yao Y, Wu G, Zhang XX, Wang W. Creation of Single Chain of Nanoscale Skyrmion Bubbles with Record-High Temperature Stability in a Geometrically Confined Nanostripe. NANO LETTERS 2018; 18:1274-1279. [PMID: 29299928 DOI: 10.1021/acs.nanolett.7b04900] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Nanoscale topologically nontrivial spin textures, such as magnetic skyrmions, have been identified as promising candidates for the transport and storage of information for spintronic applications, notably magnetic racetrack memory devices. The design and realization of a single skyrmion chain at room temperature (RT) and above in the low-dimensional nanostructures are of great importance for future practical applications. Here, we report the creation of a single skyrmion bubble chain in a geometrically confined Fe3Sn2 nanostripe with a width comparable to the featured size of a skyrmion bubble. Systematic investigations on the thermal stability have revealed that the single chain of skyrmion bubbles can keep stable at temperatures varying from RT up to a record-high temperature of 630 K. This extreme stability can be ascribed to the weak temperature-dependent magnetic anisotropy and the formation of edge states at the boundaries of the nanostripes. The realization of the highly stable skyrmion bubble chain in a geometrically confined nanostructure is a very important step toward the application of skyrmion-based spintronic devices.
Collapse
Affiliation(s)
- Zhipeng Hou
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences , Beijing 100190, China
- Physical Science and Engineering, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
| | - Qiang Zhang
- Physical Science and Engineering, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
| | - Guizhou Xu
- School of Materials Science and Engineering, Nanjing University of Science and Technology , Nanjing 210094, China
| | - Chen Gong
- Physical Science and Engineering, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
| | - Bei Ding
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences , Beijing 100190, China
| | - Yue Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences , Beijing 100190, China
| | - Hang Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences , Beijing 100190, China
| | - Enke Liu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences , Beijing 100190, China
| | - Feng Xu
- School of Materials Science and Engineering, Nanjing University of Science and Technology , Nanjing 210094, China
| | - Hongwei Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences , Beijing 100190, China
| | - Yuan Yao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences , Beijing 100190, China
| | - Guangheng Wu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences , Beijing 100190, China
| | - Xi-Xiang Zhang
- Physical Science and Engineering, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
| | - Wenhong Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences , Beijing 100190, China
| |
Collapse
|
39
|
Shibata K, Tanigaki T, Akashi T, Shinada H, Harada K, Niitsu K, Shindo D, Kanazawa N, Tokura Y, Arima TH. Current-Driven Motion of Domain Boundaries between Skyrmion Lattice and Helical Magnetic Structure. NANO LETTERS 2018; 18:929-933. [PMID: 29345472 DOI: 10.1021/acs.nanolett.7b04312] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
To utilize magnetic skyrmions, nanoscale vortex-like magnetic structures, experimental elucidation of their dynamics against current application in various circumstances such as in confined structure and mixture of different magnetic phases is indispensable. Here, we investigate the current-induced dynamics of the coexistence state of magnetic skyrmions and helical magnetic structure in a thin plate of B20-type helimagnet FeGe in terms of in situ real-space observation using Lorentz transmission electron microscopy. Current pulses with various heights and widths were applied, and the change of the magnetic domain distribution was analyzed using a machine-learning technique. The observed average driving direction of the two-magnetic-state domain boundary is opposite to the applied electric current, indicating ferromagnetic s-d exchange coupling in the spin-transfer torque mechanism. The evaluated driving distance tends to increase with increasing the pulse duration time, current density (>1 × 109 A/m2), and sample temperature, providing valuable information about hitherto unknown current-induced dynamics of the skyrmion-lattice ensemble.
Collapse
Affiliation(s)
- Kiyou Shibata
- RIKEN Center for Emergent Matter Science (CEMS) , Wako 351-0198, Japan
| | - Toshiaki Tanigaki
- Research and Development Group, Hitachi Ltd., Hatoyama 350-0395, Japan
| | - Tetsuya Akashi
- Research and Development Group, Hitachi Ltd., Hatoyama 350-0395, Japan
| | - Hiroyuki Shinada
- Research and Development Group, Hitachi Ltd., Hatoyama 350-0395, Japan
| | - Ken Harada
- RIKEN Center for Emergent Matter Science (CEMS) , Wako 351-0198, Japan
| | - Kodai Niitsu
- RIKEN Center for Emergent Matter Science (CEMS) , Wako 351-0198, Japan
| | - Daisuke Shindo
- RIKEN Center for Emergent Matter Science (CEMS) , Wako 351-0198, Japan
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University , Sendai 980-8577, Japan
| | - Naoya Kanazawa
- Department of Applied Physics, the University of Tokyo , Tokyo 113-8656, Japan
| | - Yoshinori Tokura
- RIKEN Center for Emergent Matter Science (CEMS) , Wako 351-0198, Japan
- Department of Applied Physics, the University of Tokyo , Tokyo 113-8656, Japan
| | - Taka-Hisa Arima
- RIKEN Center for Emergent Matter Science (CEMS) , Wako 351-0198, Japan
- Department of Advanced Materials Science, the University of Tokyo , Kashiwa 277-8561, Japan
| |
Collapse
|
40
|
Coherent Resonant Soft X-ray Scattering Study of Magnetic Textures in FeGe. QUANTUM BEAM SCIENCE 2018. [DOI: 10.3390/qubs2010003] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
41
|
Wu WY, Tjiu WW, Wan W, Tan HR, Teo SL, Guo S, Lim ST, Lin M. Endotaxial growth of FexGe single-crystals on Ge(001) substrates. CrystEngComm 2018. [DOI: 10.1039/c8ce00211h] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Through a 3D diffraction method combined with HRTEM images, we have successfully determined the specific phase of each FexGe island grown on the Ge substrate.
Collapse
Affiliation(s)
- Wen-Ya Wu
- Institute of Materials Research and Engineering, Agency for Science
- Technology and Research (A*STAR)
- Singapore 138634
| | - Weng Weei Tjiu
- Institute of Materials Research and Engineering, Agency for Science
- Technology and Research (A*STAR)
- Singapore 138634
| | - Wei Wan
- Department of Material and Environmental Chemistry
- Stockholm University
- Stockholm
- Sweden
| | - Hui Ru Tan
- Institute of Materials Research and Engineering, Agency for Science
- Technology and Research (A*STAR)
- Singapore 138634
| | - Siew Lang Teo
- Institute of Materials Research and Engineering, Agency for Science
- Technology and Research (A*STAR)
- Singapore 138634
| | - Shifeng Guo
- Institute of Materials Research and Engineering, Agency for Science
- Technology and Research (A*STAR)
- Singapore 138634
| | - Sze Ter Lim
- Data Storage Institute
- Agency for Science, Technology and Research (A*STAR)
- Singapore 138634
| | - Ming Lin
- Institute of Materials Research and Engineering, Agency for Science
- Technology and Research (A*STAR)
- Singapore 138634
| |
Collapse
|
42
|
Kovács A, Dunin-Borkowski RE. Magnetic Imaging of Nanostructures Using Off-Axis Electron Holography. HANDBOOK OF MAGNETIC MATERIALS 2018. [DOI: 10.1016/bs.hmm.2018.09.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
|
43
|
Weiler M, Aqeel A, Mostovoy M, Leonov A, Geprägs S, Gross R, Huebl H, Palstra TTM, Goennenwein STB. Helimagnon Resonances in an Intrinsic Chiral Magnonic Crystal. PHYSICAL REVIEW LETTERS 2017; 119:237204. [PMID: 29286698 DOI: 10.1103/physrevlett.119.237204] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Indexed: 06/07/2023]
Abstract
We experimentally study magnetic resonances in the helical and conical magnetic phases of the chiral magnetic insulator Cu_{2}OSeO_{3} at the temperature T=5 K. Using a broadband microwave spectroscopy technique based on vector network analysis, we identify three distinct sets of helimagnon resonances in the frequency range 2 GHz≤f≤20 GHz with low magnetic damping α≤0.003. The extracted resonance frequencies are in accordance with calculations of the helimagnon band structure found in an intrinsic chiral magnonic crystal. The periodic modulation of the equilibrium spin direction that leads to the formation of the magnonic crystal is a direct consequence of the chiral magnetic ordering caused by the Dzyaloshinskii-Moriya interaction. The mode coupling in the magnonic crystal allows excitation of helimagnons with wave vectors that are multiples of the spiral wave vector.
Collapse
Affiliation(s)
- Mathias Weiler
- Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, 85748 Garching, Germany
- Physik-Department, Technische Universität München, 85748 Garching, Germany
| | - Aisha Aqeel
- Zernike Institute for Advanced Materials, University of Groningen, 9700 AB Groningen, The Netherlands
| | - Maxim Mostovoy
- Zernike Institute for Advanced Materials, University of Groningen, 9700 AB Groningen, The Netherlands
| | - Andrey Leonov
- Zernike Institute for Advanced Materials, University of Groningen, 9700 AB Groningen, The Netherlands
- Center for Chiral Science, Hiroshima University, Hiroshima 739-8526, Japan
| | - Stephan Geprägs
- Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, 85748 Garching, Germany
| | - Rudolf Gross
- Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, 85748 Garching, Germany
- Physik-Department, Technische Universität München, 85748 Garching, Germany
- Nanosystems Initiative Munich, 80799 Munich, Germany
| | - Hans Huebl
- Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, 85748 Garching, Germany
- Physik-Department, Technische Universität München, 85748 Garching, Germany
- Nanosystems Initiative Munich, 80799 Munich, Germany
| | - Thomas T M Palstra
- Zernike Institute for Advanced Materials, University of Groningen, 9700 AB Groningen, The Netherlands
| | - Sebastian T B Goennenwein
- Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, 85748 Garching, Germany
- Physik-Department, Technische Universität München, 85748 Garching, Germany
- Nanosystems Initiative Munich, 80799 Munich, Germany
- Institut für Festkörper- und Materialphysik, Technische Universität Dresden, 01062 Dresden, Germany
- Center for Transport and Devices of Emergent Materials, Technische Universität Dresden, 01062 Dresden, Germany
| |
Collapse
|
44
|
Bordács S, Butykai A, Szigeti BG, White JS, Cubitt R, Leonov AO, Widmann S, Ehlers D, von Nidda HAK, Tsurkan V, Loidl A, Kézsmárki I. Equilibrium Skyrmion Lattice Ground State in a Polar Easy-plane Magnet. Sci Rep 2017; 7:7584. [PMID: 28790441 PMCID: PMC5548730 DOI: 10.1038/s41598-017-07996-x] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 07/04/2017] [Indexed: 11/09/2022] Open
Abstract
The skyrmion lattice state (SkL), a crystal built of mesoscopic spin vortices, gains its stability via thermal fluctuations in all bulk skyrmion host materials known to date. Therefore, its existence is limited to a narrow temperature region below the paramagnetic state. This stability range can drastically increase in systems with restricted geometries, such as thin films, interfaces and nanowires. Thermal quenching can also promote the SkL as a metastable state over extended temperature ranges. Here, we demonstrate more generally that a proper choice of material parameters alone guarantees the thermodynamic stability of the SkL over the full temperature range below the paramagnetic state down to zero kelvin. We found that GaV4Se8, a polar magnet with easy-plane anisotropy, hosts a robust Néel-type SkL even in its ground state. Our supporting theory confirms that polar magnets with weak uniaxial anisotropy are ideal candidates to realize SkLs with wide stability ranges.
Collapse
Affiliation(s)
- S Bordács
- Department of Physics, Budapest University of Technology and Economics and MTA-BME Lendület Magneto-optical Spectroscopy Research Group, 1111, Budapest, Hungary
| | - A Butykai
- Department of Physics, Budapest University of Technology and Economics and MTA-BME Lendület Magneto-optical Spectroscopy Research Group, 1111, Budapest, Hungary
| | - B G Szigeti
- Department of Physics, Budapest University of Technology and Economics and MTA-BME Lendület Magneto-optical Spectroscopy Research Group, 1111, Budapest, Hungary
| | - J S White
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, CH-5232, Villigen, Switzerland
| | - R Cubitt
- Institut Laue-Langevin, 6 rue Jules Horowitz, 38042, Grenoble, France
| | - A O Leonov
- Center for Chiral Science, Hiroshima University, Higashi-Hiroshima, Hiroshima, 739-8526, Japan.,Department of Chemistry, Faculty of Science, Hiroshima University Kagamiyama, Higashi Hiroshima, Hiroshima, 739-8526, Japan
| | - S Widmann
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135, Augsburg, Germany
| | - D Ehlers
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135, Augsburg, Germany
| | - H-A Krug von Nidda
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135, Augsburg, Germany
| | - V Tsurkan
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135, Augsburg, Germany.,Institute of Applied Physics, Academy of Sciences of Moldova, MD, 2028, Chisinau, Republic of Moldova
| | - A Loidl
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135, Augsburg, Germany
| | - I Kézsmárki
- Department of Physics, Budapest University of Technology and Economics and MTA-BME Lendület Magneto-optical Spectroscopy Research Group, 1111, Budapest, Hungary. .,Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135, Augsburg, Germany.
| |
Collapse
|
45
|
Helical and skyrmion lattice phases in three-dimensional chiral magnets: Effect of anisotropic interactions. Sci Rep 2017; 7:7392. [PMID: 28785054 PMCID: PMC5547169 DOI: 10.1038/s41598-017-07907-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 06/26/2017] [Indexed: 11/08/2022] Open
Abstract
In this work, we study the magnetic orders of a classical spin model with anisotropic exchanges and Dzyaloshinskii-Moriya interactions in order to understand the uniaxial stress effect in chiral magnets such as MnSi. Variational zero temperature calculations demonstrate that various helical orders can be developed depending on the interaction anisotropy magnitude, consistent with experimental observations at low temperatures. Furthermore, the uniaxial stress induced creation and annihilation of skyrmions can be also qualitatively reproduced in our Monte Carlo simulations. Our work suggests that the interaction anisotropy tuned by applied uniaxial stress may play an essential role in modulating the magnetic orders in strained chiral magnets.
Collapse
|
46
|
Jin C, Li ZA, Kovács A, Caron J, Zheng F, Rybakov FN, Kiselev NS, Du H, Blügel S, Tian M, Zhang Y, Farle M, Dunin-Borkowski RE. Control of morphology and formation of highly geometrically confined magnetic skyrmions. Nat Commun 2017; 8:15569. [PMID: 28580935 PMCID: PMC5465359 DOI: 10.1038/ncomms15569] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 04/05/2017] [Indexed: 11/09/2022] Open
Abstract
The ability to controllably manipulate magnetic skyrmions, small magnetic whirls with particle-like properties, in nanostructured elements is a prerequisite for incorporating them into spintronic devices. Here, we use state-of-the-art electron holographic imaging to directly visualize the morphology and nucleation of magnetic skyrmions in a wedge-shaped FeGe nanostripe that has a width in the range of 45–150 nm. We find that geometrically-confined skyrmions are able to adopt a wide range of sizes and ellipticities in a nanostripe that are absent in both thin films and bulk materials and can be created from a helical magnetic state with a distorted edge twist in a simple and efficient manner. We perform a theoretical analysis based on a three-dimensional general model of isotropic chiral magnets to confirm our experimental results. The flexibility and ease of formation of geometrically confined magnetic skyrmions may help to optimize the design of skyrmion-based memory devices. Proposals for skyrmion-based high-density memory devices require an understanding of the formation and shape of skyrmions in confined geometries. Here, the authors use electron holography to image magnetic textures in FeGe nanostripes and explore the parameters governing skyrmion morphology.
Collapse
Affiliation(s)
- Chiming Jin
- The Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Chinese Academy of Science (CAS), Hefei, Anhui Province 230031, China.,Department of Physics, University of Science and Technology of China, Hefei, Anhui Province 230031, China
| | - Zi-An Li
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, Jülich 52425, Germany.,Faculty of Physics and Center for Nanointegration (CENIDE), University of Duisburg-Essen, Duisburg 48047, Germany.,Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - András Kovács
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, Jülich 52425, Germany
| | - Jan Caron
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, Jülich 52425, Germany
| | - Fengshan Zheng
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, Jülich 52425, Germany
| | - Filipp N Rybakov
- M.N. Miheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences, Ekaterinburg 620990, Russia.,Ural Federal University, Ekaterinburg 620002, Russia.,KTH Royal Institute of Technology, Stockholm SE-10691, Sweden
| | - Nikolai S Kiselev
- Peter Grünberg Institute and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, Jülich 52425, Germany
| | - Haifeng Du
- The Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Chinese Academy of Science (CAS), Hefei, Anhui Province 230031, China.,Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Jiangsu Province 210093, China
| | - Stefan Blügel
- Peter Grünberg Institute and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, Jülich 52425, Germany
| | - Mingliang Tian
- The Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Chinese Academy of Science (CAS), Hefei, Anhui Province 230031, China.,Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Jiangsu Province 210093, China
| | - Yuheng Zhang
- The Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Chinese Academy of Science (CAS), Hefei, Anhui Province 230031, China.,Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Jiangsu Province 210093, China
| | - Michael Farle
- Faculty of Physics and Center for Nanointegration (CENIDE), University of Duisburg-Essen, Duisburg 48047, Germany.,Center of Functionalized Magnetic Materials, Immanuel Kant Baltic Federal University, Kaliningrad 236041, Russian Federation
| | - Rafal E Dunin-Borkowski
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, Jülich 52425, Germany
| |
Collapse
|
47
|
Pöllath S, Wild J, Heinen L, Meier TNG, Kronseder M, Tutsch L, Bauer A, Berger H, Pfleiderer C, Zweck J, Rosch A, Back CH. Dynamical Defects in Rotating Magnetic Skyrmion Lattices. PHYSICAL REVIEW LETTERS 2017; 118:207205. [PMID: 28581772 DOI: 10.1103/physrevlett.118.207205] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Indexed: 06/07/2023]
Abstract
The chiral magnet Cu_{2}OSeO_{3} hosts a Skyrmion lattice that may be equivalently described as a superposition of plane waves or a lattice of particlelike topological objects. A thermal gradient may break up the Skyrmion lattice and induce rotating domains, raising the question of which of these scenarios better describes the violent dynamics at the domain boundaries. Here, we show that in an inhomogeneous temperature gradient caused by illumination in a Lorentz transmission electron microscope different parts of the Skyrmion lattice can be set into motion with different angular velocities. Tracking the time dependence, we show that the constant rearrangement of domain walls is governed by dynamic 5-7 defects arranging into lines. An analysis of the associated defect density is described by Frank's equation and agrees well with classical 2D Monte Carlo simulations. Fluctuations of boundaries show a surgelike rearrangement of Skyrmion clusters driven by defect rearrangement consistent with simulations treating Skyrmions as point particles. Our findings underline the particle character of the Skyrmion.
Collapse
Affiliation(s)
- S Pöllath
- Institut für Experimentelle Physik, Universität Regensburg, Universitätsstraße 31, D-93040 Regensburg, Germany
| | - J Wild
- Institut für Experimentelle Physik, Universität Regensburg, Universitätsstraße 31, D-93040 Regensburg, Germany
| | - L Heinen
- Institut für Theoretische Physik, Universität zu Köln, D-50937 Köln, Germany
| | - T N G Meier
- Institut für Experimentelle Physik, Universität Regensburg, Universitätsstraße 31, D-93040 Regensburg, Germany
| | - M Kronseder
- Institut für Experimentelle Physik, Universität Regensburg, Universitätsstraße 31, D-93040 Regensburg, Germany
| | - L Tutsch
- Institut für Experimentelle Physik, Universität Regensburg, Universitätsstraße 31, D-93040 Regensburg, Germany
| | - A Bauer
- Physik-Department, Technische Universität München, D-85748 Garching, Germany
| | - H Berger
- Crystal Growth Facility, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - C Pfleiderer
- Physik-Department, Technische Universität München, D-85748 Garching, Germany
| | - J Zweck
- Institut für Experimentelle Physik, Universität Regensburg, Universitätsstraße 31, D-93040 Regensburg, Germany
| | - A Rosch
- Institut für Theoretische Physik, Universität zu Köln, D-50937 Köln, Germany
| | - C H Back
- Institut für Experimentelle Physik, Universität Regensburg, Universitätsstraße 31, D-93040 Regensburg, Germany
| |
Collapse
|
48
|
Stepanov EA, Dutreix C, Katsnelson MI. Dynamical and Reversible Control of Topological Spin Textures. PHYSICAL REVIEW LETTERS 2017; 118:157201. [PMID: 28452553 DOI: 10.1103/physrevlett.118.157201] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Indexed: 06/07/2023]
Abstract
Recent observations of topological spin textures brought spintronics one step closer to new magnetic memories. Nevertheless, the existence of Skyrmions, as well as their stabilization, require very specific intrinsic magnetic properties which are usually fixed in magnets. Here we address the possibility to dynamically control their intrinsic magnetic interactions by varying the strength of a high-frequency laser field. It is shown that drastic changes can be induced in the antiferromagnetic exchange interactions and the latter can even be reversed to become ferromagnetic, provided the direct exchange is already non-negligible in equilibrium as predicted, for example, in Si doped with C, Sn, or Pb adatoms. In the presence of Dzyaloshinskii-Moriya interactions, this enables us to tune features of ferromagnetic Skyrmions such as their radius, making them easier to stabilize. Alternatively, such topological spin textures can occur in frustrated triangular lattices. Then, we demonstrate that a high-frequency laser field can induce dynamical frustration in antiferromagnets, where the degree of frustration can subsequently be tuned suitably to drive the material toward a Skyrmionic phase.
Collapse
Affiliation(s)
- E A Stepanov
- Radboud University, Institute for Molecules and Materials, Heyendaalseweg 135, 6525AJ Nijmegen, Netherlands
| | - C Dutreix
- Radboud University, Institute for Molecules and Materials, Heyendaalseweg 135, 6525AJ Nijmegen, Netherlands
- Univ Lyon, Ens de Lyon, Univ Claude Bernard, CNRS, Laboratoire de Physique, F-69342 Lyon, France
| | - M I Katsnelson
- Radboud University, Institute for Molecules and Materials, Heyendaalseweg 135, 6525AJ Nijmegen, Netherlands
| |
Collapse
|
49
|
Observation of stable Néel skyrmions in cobalt/palladium multilayers with Lorentz transmission electron microscopy. Nat Commun 2017; 8:14761. [PMID: 28281542 PMCID: PMC5353624 DOI: 10.1038/ncomms14761] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 01/30/2017] [Indexed: 11/16/2022] Open
Abstract
Néel skyrmions are of high interest due to their potential applications in a variety of spintronic devices, currently accessible in ultrathin heavy metal/ferromagnetic bilayers and multilayers with a strong Dzyaloshinskii–Moriya interaction. Here we report on the direct imaging of chiral spin structures including skyrmions in an exchange-coupled cobalt/palladium multilayer at room temperature with Lorentz transmission electron microscopy, a high-resolution technique previously suggested to exhibit no Néel skyrmion contrast. Phase retrieval methods allow us to map the internal spin structure of the skyrmion core, identifying a 25 nm central region of uniform magnetization followed by a larger region characterized by rotation from in- to out-of-plane. The formation and resolution of the internal spin structure of room temperature skyrmions without a stabilizing out-of-plane field in thick magnetic multilayers opens up a new set of tools and materials to study the physics and device applications associated with chiral ordering and skyrmions. Néel skyrmions are spin textures with a magnetization that rotates from in- to out-of-plane with distance from its centre. Here, the authors show that Lorentz transmission electron microscopy can be used to directly image Néel skyrmions with high resolution in thick exchange-coupled magnetic multilayers.
Collapse
|
50
|
Morikawa D, Yu X, Karube K, Tokunaga Y, Taguchi Y, Arima TH, Tokura Y. Deformation of Topologically-Protected Supercooled Skyrmions in a Thin Plate of Chiral Magnet Co 8Zn 8Mn 4. NANO LETTERS 2017; 17:1637-1641. [PMID: 28135106 DOI: 10.1021/acs.nanolett.6b04821] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Magnetic skyrmions in Co8Zn8Mn4 thin plates are observed to deform in a metastable state prepared in a magnetic-field-cooling process by way of the thermal-equilibrium skyrmion phase. In cooling, the disk-shape skyrmions change to bar- or L-shaped elongated form, whereas the skyrmion density is nearly conserved. The deformation of the skyrmions in the supercooled metastable phase is observed irrespective of the crystallographic orientation of the thin plate, whereas the elongation direction nearly aligns along the magnetic easy axis. It is proposed that the deformation should be induced by a large increase in magnetic modulation wavenumber when decreasing the temperature, whereas the topological protection of the skyrmions keeps the averaged skyrmion density constant.
Collapse
Affiliation(s)
- Daisuke Morikawa
- RIKEN Center for Emergent Matter Science (CEMS) , Wako 351-0198, Japan
| | - Xiuzhen Yu
- RIKEN Center for Emergent Matter Science (CEMS) , Wako 351-0198, Japan
| | - Kosuke Karube
- RIKEN Center for Emergent Matter Science (CEMS) , Wako 351-0198, Japan
| | - Yusuke Tokunaga
- Department of Advanced Materials Science, University of Tokyo , Kashiwa 277-8561, Japan
| | - Yasujiro Taguchi
- RIKEN Center for Emergent Matter Science (CEMS) , Wako 351-0198, Japan
| | - Taka-Hisa Arima
- RIKEN Center for Emergent Matter Science (CEMS) , Wako 351-0198, Japan
- Department of Advanced Materials Science, University of Tokyo , Kashiwa 277-8561, Japan
| | - Yoshinori Tokura
- RIKEN Center for Emergent Matter Science (CEMS) , Wako 351-0198, Japan
- Department of Applied Physics and Quantum Phase Electronics Center (QPEC), University of Tokyo , Tokyo 113-8656, Japan
| |
Collapse
|