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He Z, Li Z, Chen Z, Wang Z, Shen J, Wang S, Song C, Zhao T, Cai J, Lin SZ, Zhang Y, Shen B. Experimental observation of current-driven antiskyrmion sliding in stripe domains. NATURE MATERIALS 2024; 23:1048-1054. [PMID: 38605194 DOI: 10.1038/s41563-024-01870-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Accepted: 03/18/2024] [Indexed: 04/13/2024]
Abstract
Magnetic skyrmions are promising as next-generation information units. Their antiparticle-the antiskyrmion-has also been discovered in chiral magnets. Here we experimentally demonstrate antiskyrmion sliding in response to a pulsed electric current at room temperature without the requirement of an external magnetic field. This is realized by embedding antiskyrmions in helical stripe domains, which naturally provide one-dimensional straight tracks along which antiskyrmion sliding can be easily launched with low current density and without transverse deflection from the antiskyrmion Hall effect. The higher mobility of the antiskyrmions in the background of helical stripes in contrast to the typical ferromagnetic state is a result of intrinsic material parameters and elastic energy of the stripe domain, thereby smearing out the random pinning potential, as supported by micromagnetic simulations. The demonstration and comprehensive understanding of antiskyrmion movement along naturally straight tracks offers a new perspective for (anti)skyrmion application in spintronics.
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Affiliation(s)
- Zhidong He
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Zhuolin Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Zhaohui Chen
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing, China
| | - Zhan Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Jun Shen
- Department of Energy and Power Engineering, School of Mechanical Engineering, Beijing Institute of Technology, Beijing, China
| | - Shouguo Wang
- Anhui Key Laboratory of Magnetic Functional Materials and Devices, School of Materials Science and Engineering, Anhui University, Hefei, China
| | - Cheng Song
- Key Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing, China
| | - Tongyun Zhao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Jianwang Cai
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Shi-Zeng Lin
- Theoretical Division and Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, USA.
| | - Ying Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China.
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China.
- Songshan Lake Materials Laboratory, Dongguan, China.
| | - Baogen Shen
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
- Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, Ningbo, China
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2
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Wang Y, Xing J, Zhao Y, Wang Y, Zhao J, Jiang X. Alloying Driven Antiferromagnetic Skyrmions on NiPS 3 Monolayer: A First-Principles Calculation. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2401048. [PMID: 38647400 PMCID: PMC11220710 DOI: 10.1002/advs.202401048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Revised: 03/25/2024] [Indexed: 04/25/2024]
Abstract
Topological magnetic states are promising information carriers for ultrahigh-density and high-efficiency magnetic storage. Recent advances in two-dimensional (2D) magnets provide powerful platforms for stabilizing various nanometer-size topological spin textures within a wide range of magnetic field and temperature. However, non-centrosymmetric 2D magnets with broken inversion symmetry are scarce in nature, making direct observations of the chiral spin structure difficult, especially for antiferromagnetic (AFM) skyrmions. In this work, it is theoretically predicted that intrinsic AFM skyrmions can be easily triggered in XY-type honeycomb magnet NiPS3 monolayer by alloying of Cr atoms, due to the presence of a sizable Dzyaloshinskii-Moriya interaction. More interestingly, the diameter of the AFM skyrmions in Ni3/4Cr1/4PS3 decreases from 12 to 4.4 nm as the external magnetic field increases and the skyrmion phases remain stable up to an external magnetic field of 4 T. These results highlight an effective strategy to generate and modulate the topological spin texture in 2D magnets by alloying with magnetic element.
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Affiliation(s)
- Yanxia Wang
- Key Laboratory of Materials Modification by LaserIon and Electron BeamsDalian University of TechnologyMinistry of EducationDalian116024China
| | - Jianpei Xing
- Key Laboratory of Materials Modification by LaserIon and Electron BeamsDalian University of TechnologyMinistry of EducationDalian116024China
| | - Ying Zhao
- Key Laboratory of Materials Modification by LaserIon and Electron BeamsDalian University of TechnologyMinistry of EducationDalian116024China
| | - Yi Wang
- Key Laboratory of Materials Modification by LaserIon and Electron BeamsDalian University of TechnologyMinistry of EducationDalian116024China
| | - Jijun Zhao
- Key Laboratory of Materials Modification by LaserIon and Electron BeamsDalian University of TechnologyMinistry of EducationDalian116024China
- Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum MaterialsSchool of PhysicsSouth China Normal UniversityGuangzhou510006China
- Guangdong‐Hong Kong Joint Laboratory of Quantum MatterFrontier Research Institute for PhysicsSouth China Normal UniversityGuangzhou510006China
| | - Xue Jiang
- Key Laboratory of Materials Modification by LaserIon and Electron BeamsDalian University of TechnologyMinistry of EducationDalian116024China
- Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum MaterialsSchool of PhysicsSouth China Normal UniversityGuangzhou510006China
- Guangdong‐Hong Kong Joint Laboratory of Quantum MatterFrontier Research Institute for PhysicsSouth China Normal UniversityGuangzhou510006China
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3
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Zhou Y, Li S, Liang X, Zhou Y. Topological Spin Textures: Basic Physics and Devices. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024:e2312935. [PMID: 38861696 DOI: 10.1002/adma.202312935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 05/24/2024] [Indexed: 06/13/2024]
Abstract
In the face of escalating modern data storage demands and the constraints of Moore's Law, exploring spintronic solutions, particularly the devices based on magnetic skyrmions, has emerged as a promising frontier in scientific research. Since the first experimental observation of skyrmions, topological spin textures have been extensively studied for their great potential as efficient information carriers in spintronic devices. However, significant challenges have emerged alongside this progress. This review aims to synthesize recent advances in skyrmion research while addressing the major issues encountered in the field. Additionally, current research on promising topological spin structures in addition to skyrmions is summarized. Beyond 2D structures, exploration also extends to 1D magnetic solitons and 3D spin textures. In addition, a diverse array of emerging magnetic materials is introduced, including antiferromagnets and 2D van der Waals magnets, broadening the scope of potential materials hosting topological spin textures. Through a systematic examination of magnetic principles, topological categorization, and the dynamics of spin textures, a comprehensive overview of experimental and theoretical advances in the research of topological magnetism is provided. Finally, both conventional and unconventional applications are summarized based on spin textures proposed thus far. This review provides an outlook on future development in applied spintronics.
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Affiliation(s)
- Yuqing Zhou
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, Guangdong, 518172, China
| | - Shuang Li
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, Guangdong, 518172, China
| | - Xue Liang
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, Guangdong, 518172, China
| | - Yan Zhou
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, Guangdong, 518172, China
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4
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Lee J, Park HR, Jin KH, Kim JS, Cheong SW, Yeom HW. Topological Complex Charge Conservation in Nontrivial Z 2 × Z 2 Domain Walls. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2313803. [PMID: 38482920 DOI: 10.1002/adma.202313803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Revised: 02/14/2024] [Indexed: 03/22/2024]
Abstract
Localized topological modes such as solitons, Majorana Fermions, and skyrmions are attracting great interest as robust information carriers for future devices. Here, a novel conserved quantity for topological domain wall networks of a Z2 × Z2 order generated with spin-polarized current in Sr2VO3FeAs is discovered. Domain walls are mobilized by the scanning tunneling current, which also observes in atomic scale active dynamics of domain wall vertices including merge, bifurcation, pair creation, and annihilation. Within this dynamics, the product of the topological complex charges defined for domain wall vertices is conserved with a novel boundary-charge correspondence rule. These results may open an avenue toward topological electronics based on domain wall vertices in generic Z2 × Z2 systems.
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Affiliation(s)
- Jhinhwan Lee
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
| | - Hae-Ryong Park
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Kyung-Hwan Jin
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
| | - Jun Sung Kim
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Sang-Wook Cheong
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, 08854, USA
| | - Han-Woong Yeom
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
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5
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Huai X, Acheampong E, Delles E, Winiarski MJ, Sorolla M, Nassar L, Liang M, Ramette C, Ji H, Scheie A, Calder S, Mourigal M, Tran TT. Noncentrosymmetric Triangular Magnet CaMnTeO 6: Strong Quantum Fluctuations and Role of s 0 versus s 2 Electronic States in Competing Exchange Interactions. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2313763. [PMID: 38506567 DOI: 10.1002/adma.202313763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Revised: 03/12/2024] [Indexed: 03/21/2024]
Abstract
Noncentrosymmetric triangular magnets offer a unique platform for realizing strong quantum fluctuations. However, designing these quantum materials remains an open challenge attributable to a knowledge gap in the tunability of competing exchange interactions at the atomic level. Here, a new noncentrosymmetric triangular S = 3/2 magnet CaMnTeO6 is created based on careful chemical and physical considerations. The model material displays competing magnetic interactions and features nonlinear optical responses with the capability of generating coherent photons. The incommensurate magnetic ground state of CaMnTeO6 with an unusually large spin rotation angle of 127°(1) indicates that the anisotropic interlayer exchange is strong and competing with the isotropic interlayer Heisenberg interaction. The moment of 1.39(1) µB, extracted from low-temperature heat capacity and neutron diffraction measurements, is only 46% of the expected value of the static moment 3 µB. This reduction indicates the presence of strong quantum fluctuations in the half-integer spin S = 3/2 CaMnTeO6 magnet, which is rare. By comparing the spin-polarized band structure, chemical bonding, and physical properties of AMnTeO6 (A = Ca, Sr, Pb), how quantum-chemical interpretation can illuminate insights into the fundamentals of magnetic exchange interactions, providing a powerful tool for modulating spin dynamics with atomically precise control is demonstrated.
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Affiliation(s)
- Xudong Huai
- Department of Chemistry, Clemson University, Clemson, SC, 29634, USA
| | | | - Erich Delles
- Department of Chemistry, Clemson University, Clemson, SC, 29634, USA
| | - Michał J Winiarski
- Applied Physics and Mathematics and Advanced Materials Center, Gdansk University of Technology, Gdansk, 80-233, Poland
| | - Maurice Sorolla
- Institute of Chemistry, University of the Philippines Diliman, Quezon City, 1101, Philippines
| | - Lila Nassar
- School of Physics, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Mingli Liang
- Department of Chemistry, University of Houston, Houston, TX, 77204, USA
| | - Caleb Ramette
- Department of Materials Science and Engineering, University of Utah, Salt Lake City, UT, 84112, USA
| | - Huiwen Ji
- Department of Materials Science and Engineering, University of Utah, Salt Lake City, UT, 84112, USA
| | - Allen Scheie
- MPA-Q, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Stuart Calder
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Martin Mourigal
- School of Physics, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Thao T Tran
- Department of Chemistry, Clemson University, Clemson, SC, 29634, USA
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6
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Zhang H, Shao YT, Chen X, Zhang B, Wang T, Meng F, Xu K, Meisenheimer P, Chen X, Huang X, Behera P, Husain S, Zhu T, Pan H, Jia Y, Settineri N, Giles-Donovan N, He Z, Scholl A, N'Diaye A, Shafer P, Raja A, Xu C, Martin LW, Crommie MF, Yao J, Qiu Z, Majumdar A, Bellaiche L, Muller DA, Birgeneau RJ, Ramesh R. Spin disorder control of topological spin texture. Nat Commun 2024; 15:3828. [PMID: 38714653 PMCID: PMC11076609 DOI: 10.1038/s41467-024-47715-5] [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: 01/24/2024] [Accepted: 04/10/2024] [Indexed: 05/10/2024] Open
Abstract
Stabilization of topological spin textures in layered magnets has the potential to drive the development of advanced low-dimensional spintronics devices. However, achieving reliable and flexible manipulation of the topological spin textures beyond skyrmion in a two-dimensional magnet system remains challenging. Here, we demonstrate the introduction of magnetic iron atoms between the van der Waals gap of a layered magnet, Fe3GaTe2, to modify local anisotropic magnetic interactions. Consequently, we present direct observations of the order-disorder skyrmion lattices transition. In addition, non-trivial topological solitons, such as skyrmioniums and skyrmion bags, are realized at room temperature. Our work highlights the influence of random spin control of non-trivial topological spin textures.
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Affiliation(s)
- Hongrui Zhang
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA.
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
| | - Yu-Tsun Shao
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA, 90089, USA
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, 14853, USA
| | - Xiang Chen
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
- Department of Physics, University of California, Berkeley, CA, 94720, USA.
- Center for Neutron Science and Technology, School of Physics, Sun Yat-Sen University, Guangzhou, Guangdong, 510275, China.
| | - Binhua Zhang
- Key Laboratory of Computational Physical Sciences (Ministry of Education), Institute of Computational Physical Sciences, State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai, 200433, China
- Shanghai Qi Zhi Institute, Shanghai, 200030, China
| | - Tianye Wang
- Department of Physics, University of California, Berkeley, CA, 94720, USA
| | - Fanhao Meng
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Kun Xu
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA
| | - Peter Meisenheimer
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Xianzhe Chen
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Xiaoxi Huang
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Piush Behera
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Sajid Husain
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Tiancong Zhu
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Physics, University of California, Berkeley, CA, 94720, USA
| | - Hao Pan
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Yanli Jia
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Nick Settineri
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | | | - Zehao He
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Physics, University of California, Berkeley, CA, 94720, USA
| | - Andreas Scholl
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Alpha N'Diaye
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Padraic Shafer
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Archana Raja
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Changsong Xu
- Key Laboratory of Computational Physical Sciences (Ministry of Education), Institute of Computational Physical Sciences, State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai, 200433, China.
- Shanghai Qi Zhi Institute, Shanghai, 200030, China.
| | - Lane W Martin
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Materials Science and NanoEngineering, Rice University, Houston, TX, 77005, USA
- Department of Chemistry, Rice University, Houston, TX, 77005, USA
- Department of Physics and Astronomy, Rice University, Houston, TX, 77005, USA
- Rice Advanced Materials Institute, Rice University, Houston, TX, 77005, USA
| | - Michael F Crommie
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Physics, University of California, Berkeley, CA, 94720, USA
| | - Jie Yao
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Ziqiang Qiu
- Department of Physics, University of California, Berkeley, CA, 94720, USA
| | - Arun Majumdar
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA
| | - Laurent Bellaiche
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, AR, 72701, USA
| | - David A Muller
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, 14853, USA
- Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, NY, 14853, USA
| | - Robert J Birgeneau
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Physics, University of California, Berkeley, CA, 94720, USA
| | - Ramamoorthy Ramesh
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA.
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
- Department of Physics, University of California, Berkeley, CA, 94720, USA.
- Department of Materials Science and NanoEngineering, Rice University, Houston, TX, 77005, USA.
- Department of Physics and Astronomy, Rice University, Houston, TX, 77005, USA.
- Rice Advanced Materials Institute, Rice University, Houston, TX, 77005, USA.
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7
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Yasin FS, Masell J, Takahashi Y, Akashi T, Baba N, Karube K, Shindo D, Arima T, Taguchi Y, Tokura Y, Tanigaki T, Yu X. Bloch Point Quadrupole Constituting Hybrid Topological Strings Revealed with Electron Holographic Vector Field Tomography. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2311737. [PMID: 38219021 DOI: 10.1002/adma.202311737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 12/22/2023] [Indexed: 01/15/2024]
Abstract
Topological magnetic (anti)skyrmions are robust string-like objects heralded as potential components in next-generation topological spintronics devices due to their low-energy manipulability via stimuli such as magnetic fields, heat, and electric/thermal current. While these 2D topological objects are widely studied, intrinsically 3D electron-spin real-space topology remains less explored despite its prevalence in bulky magnets. 2D-imaging studies reveal peculiar vortex-like contrast in the core regions of spin textures present in antiskyrmion-hosting thin plate magnets with S4 crystal symmetry, suggesting a more complex 3D real-space structure than the 2D model suggests. Here, holographic vector field electron tomography captures the 3D structure of antiskyrmions in a single-crystal, precision-doped (Fe0.63Ni0.3Pd0.07)3P (FNPP) lamellae at room temperature and zero field. These measurements reveal hybrid string-like solitons composed of skyrmions with topological number W = -1 on the lamellae's surfaces and an antiskyrmion (W = + 1) connecting them. High-resolution images uncover a Bloch point quadrupole (four magnetic (anti)monopoles that are undetectable in 2D imaging) which enables the observed lengthwise topological transitions. Numerical calculations corroborate the stability of hybrid strings over their conventional (anti)skyrmion counterparts. Hybrid strings result in topological tuning, a tunable topological Hall effect, and the suppression of skyrmion Hall motion, disrupting existing paradigms within spintronics.
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Affiliation(s)
- Fehmi Sami Yasin
- RIKEN Center for Emergent Matter Science (CEMS), RIKEN, Wako, 351-0198, Japan
| | - Jan Masell
- RIKEN Center for Emergent Matter Science (CEMS), RIKEN, Wako, 351-0198, Japan
- Institute of Theoretical Solid State Physics, Karlsruhe Institute of Technology (KIT), 76049, Karlsruhe, Germany
| | - Yoshio Takahashi
- Research and Development Group, Hitachi Ltd., Hatoyama, 350-0395, Japan
| | - Tetsuya Akashi
- Research and Development Group, Hitachi Ltd., Hatoyama, 350-0395, Japan
| | - Norio Baba
- Research Institute for Science and Technology, Kogakuin University, Hachioji, 192-0015, Japan
| | - Kosuke Karube
- RIKEN Center for Emergent Matter Science (CEMS), RIKEN, Wako, 351-0198, Japan
| | - Daisuke Shindo
- RIKEN Center for Emergent Matter Science (CEMS), RIKEN, Wako, 351-0198, Japan
| | - Takahisa Arima
- RIKEN Center for Emergent Matter Science (CEMS), RIKEN, Wako, 351-0198, Japan
- Department of Advanced Materials Science, University of Tokyo, Kashiwa, 277-8561, Japan
| | - Yasujiro Taguchi
- RIKEN Center for Emergent Matter Science (CEMS), RIKEN, Wako, 351-0198, Japan
| | - Yoshinori Tokura
- RIKEN Center for Emergent Matter Science (CEMS), RIKEN, Wako, 351-0198, Japan
- Department of Applied Physics, University of Tokyo, Tokyo, 113-8656, Japan
- Tokyo College, University of Tokyo, Tokyo, 113-8656, Japan
| | - Toshiaki Tanigaki
- Research and Development Group, Hitachi Ltd., Hatoyama, 350-0395, Japan
| | - Xiuzhen Yu
- RIKEN Center for Emergent Matter Science (CEMS), RIKEN, Wako, 351-0198, Japan
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8
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Gopi AK, Srivastava AK, Sharma AK, Chakraborty A, Das S, Deniz H, Ernst A, Hazra BK, Meyerheim HL, Parkin SSP. Thickness-Tunable Zoology of Magnetic Spin Textures Observed in Fe 5GeTe 2. ACS NANO 2024. [PMID: 38315563 PMCID: PMC10883052 DOI: 10.1021/acsnano.3c09602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2024]
Abstract
The family of two-dimensional (2D) van der Waals (vdW) materials provides a playground for tuning structural and magnetic interactions to create a wide variety of spin textures. Of particular interest is the ferromagnetic compound Fe5GeTe2 that we show displays a range of complex spin textures as well as complex crystal structures. Here, using a high-brailliance laboratory X-ray source, we show that the majority (1 × 1) Fe5GeTe2 (FGT5) phase exhibits a structure that was previously considered as being centrosymmetric but rather lacks inversion symmetry. In addition, FGT5 exhibits a minority phase that exhibits a long-range ordered (√3 × √3)-R30° superstructure. This superstructure is highly interesting in that it is innately 2D without any lattice periodicity perpendicular to the vdW layers, and furthermore, the superstructure is a result of ordered Te vacancies in one of the topmost layers of the FGT5 sheets rather than being a result of vertical Fe ordering as earlier suggested. We show, from direct real-space magnetic imaging, evidence for three distinct magnetic ground states in lamellae of FGT5 that are stabilized with increasing lamella thickness, namely, a multidomain state, a stripe phase, and an unusual fractal state. In the stripe phase we also observe unconventional type-I and type-II bubbles where the spin texture in the central region of the bubbles is nonuniform, unlike conventional bubbles. In addition, we find a bobber or a cocoon-like spin texture in thick (∼170 μm) FGT5 that emerges from the fractal state in the presence of a magnetic field. Among all the 2D vdW magnets we have thus demonstrated that FGT5 hosts perhaps the richest variety of magnetic phases that, thereby, make it a highly interesting platform for the subtle tuning of magnetic interactions.
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Affiliation(s)
- Ajesh K Gopi
- Max Planck Institute of Microstructure Physics, Weinberg 2, Halle (Saale) D-06120, Germany
| | - Abhay K Srivastava
- Max Planck Institute of Microstructure Physics, Weinberg 2, Halle (Saale) D-06120, Germany
| | - Ankit K Sharma
- Max Planck Institute of Microstructure Physics, Weinberg 2, Halle (Saale) D-06120, Germany
| | - Anirban Chakraborty
- Max Planck Institute of Microstructure Physics, Weinberg 2, Halle (Saale) D-06120, Germany
| | - Souvik Das
- Max Planck Institute of Microstructure Physics, Weinberg 2, Halle (Saale) D-06120, Germany
| | - Hakan Deniz
- Max Planck Institute of Microstructure Physics, Weinberg 2, Halle (Saale) D-06120, Germany
| | - Arthur Ernst
- Johannes Kepler University, Altenbergerstraβe 69, Linz 4040, Austria
| | - Binoy K Hazra
- Max Planck Institute of Microstructure Physics, Weinberg 2, Halle (Saale) D-06120, Germany
| | - Holger L Meyerheim
- Max Planck Institute of Microstructure Physics, Weinberg 2, Halle (Saale) D-06120, Germany
| | - Stuart S P Parkin
- Max Planck Institute of Microstructure Physics, Weinberg 2, Halle (Saale) D-06120, Germany
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9
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Singh D, Fujishiro Y, Hayami S, Moody SH, Nomoto T, Baral PR, Ukleev V, Cubitt R, Steinke NJ, Gawryluk DJ, Pomjakushina E, Ōnuki Y, Arita R, Tokura Y, Kanazawa N, White JS. Transition between distinct hybrid skyrmion textures through their hexagonal-to-square crystal transformation in a polar magnet. Nat Commun 2023; 14:8050. [PMID: 38052859 DOI: 10.1038/s41467-023-43814-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Accepted: 11/21/2023] [Indexed: 12/07/2023] Open
Abstract
Magnetic skyrmions, topological vortex-like spin textures, garner significant interest due to their unique properties and potential applications in nanotechnology. While they typically form a hexagonal crystal with distinct internal magnetisation textures known as Bloch- or Néel-type, recent theories suggest the possibility for direct transitions between skyrmion crystals of different lattice structures and internal textures. To date however, experimental evidence for these potentially useful phenomena have remained scarce. Here, we discover the polar tetragonal magnet EuNiGe3 to host two hybrid skyrmion phases, each with distinct internal textures characterised by anisotropic combinations of Bloch- and Néel-type windings. Variation of the magnetic field drives a direct transition between the two phases, with the modification of the hybrid texture concomitant with a hexagonal-to-square skyrmion crystal transformation. We explain these observations with a theory that includes the key ingredients of momentum-resolved Ruderman-Kittel-Kasuya-Yosida and Dzyaloshinskii-Moriya interactions that compete at the observed low symmetry magnetic skyrmion crystal wavevectors. Our findings underscore the potential of polar magnets with rich interaction schemes as promising for discovering new topological magnetic phases.
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Affiliation(s)
- Deepak Singh
- Laboratory for Neutron Scattering and Imaging (LNS), Paul Scherrer Institute (PSI), CH-5232, Villigen, Switzerland.
| | - Yukako Fujishiro
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama, 351-0198, Japan
| | - Satoru Hayami
- Graduate School of Science, Hokkaido University, Sapporo, 060-0810, Japan
| | - Samuel H Moody
- Laboratory for Neutron Scattering and Imaging (LNS), Paul Scherrer Institute (PSI), CH-5232, Villigen, Switzerland
| | - Takuya Nomoto
- Research Center for Advanced Science and Technology, University of Tokyo, Komaba, Meguro-ku, Tokyo, 153-8904, Japan
| | - Priya R Baral
- Laboratory for Neutron Scattering and Imaging (LNS), Paul Scherrer Institute (PSI), CH-5232, Villigen, Switzerland
| | - Victor Ukleev
- Helmholtz-Zentrum Berlin für Materialien und Energie, D-14109, Berlin, Germany
| | - Robert Cubitt
- Institut-Laue-Langevin, 6 rue Jules Horowitz, Grenoble, 38000, France
| | | | - Dariusz J Gawryluk
- Laboratory for Multiscale Materials Experiments (LMX), Paul Scherrer Institut (PSI), CH-5232, Villigen PSI, Switzerland
| | - Ekaterina Pomjakushina
- Laboratory for Multiscale Materials Experiments (LMX), Paul Scherrer Institut (PSI), CH-5232, Villigen PSI, Switzerland
| | - Yoshichika Ōnuki
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama, 351-0198, Japan
| | - Ryotaro Arita
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama, 351-0198, Japan
- Research Center for Advanced Science and Technology, University of Tokyo, Komaba, Meguro-ku, Tokyo, 153-8904, Japan
| | - Yoshinori Tokura
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama, 351-0198, Japan
- Department of Applied Physics, The University of Tokyo, Bunkyo, Tokyo, 113-8656, Japan
| | - Naoya Kanazawa
- Institute of Industrial Science, The University of Tokyo, Meguro-ku, Tokyo, 153-8505, Japan
| | - Jonathan S White
- Laboratory for Neutron Scattering and Imaging (LNS), Paul Scherrer Institute (PSI), CH-5232, Villigen, Switzerland.
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10
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Yasin FS, Masell J, Karube K, Shindo D, Taguchi Y, Tokura Y, Yu X. Heat current-driven topological spin texture transformations and helical q-vector switching. Nat Commun 2023; 14:7094. [PMID: 37925467 PMCID: PMC10625536 DOI: 10.1038/s41467-023-42846-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 10/24/2023] [Indexed: 11/06/2023] Open
Abstract
The use of magnetic states in memory devices has a history dating back decades, and the experimental discovery of magnetic skyrmions and subsequent demonstrations of their control via magnetic fields, heat, and electric/thermal currents have ushered in a new era for spintronics research and development. Recent studies have experimentally discovered the antiskyrmion, the skyrmion's antiparticle, and while several host materials have been identified, control via thermal current remains elusive. In this work, we use thermal current to drive the transformation between skyrmions, antiskyrmions and non-topological bubbles, as well as the switching of helical states in the antiskyrmion-hosting ferromagnet (Fe0.63Ni0.3Pd0.07)3P at room temperature. We discover that a temperature gradient [Formula: see text] drives a transformation from antiskyrmions to non-topological bubbles to skyrmions while under a magnetic field and observe the opposite, unidirectional transformation from skyrmions to antiskyrmions at zero-field, suggesting that the antiskyrmion, more so than the skyrmion, is robustly metastable at zero field.
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Affiliation(s)
- Fehmi Sami Yasin
- 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), 76049, Karlsruhe, Germany
| | - Kosuke Karube
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
| | - Daisuke Shindo
- 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
- Department of Applied Physics, University of Tokyo, Tokyo, 113-8656, Japan
- Tokyo College, University of Tokyo, Tokyo, 113-8656, Japan
| | - Xiuzhen Yu
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan.
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11
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Tatarskiy DA, Gusev NS, Gusev SA. A method for estimating magnetic field of TEM objective lens. Ultramicroscopy 2023; 253:113822. [PMID: 37586244 DOI: 10.1016/j.ultramic.2023.113822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 06/29/2023] [Accepted: 07/25/2023] [Indexed: 08/18/2023]
Abstract
We propose a method for calibration of magnetic field in the objective lens of transmission electron microscope. The calibration process is based on classical Fresnel imaging of Permalloy disks and measuring the displacement of the magnetic vortex core when the sample is tilted at various excitations of the objective lens. We adopted the Carl Zeiss LIBRA 200 MC transmission electron microscope for Lorentz electron microscopy using this method. The objective lens magnetic field evaluation is tested on the Co/Pt multilayered films with known magnetic properties.
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Affiliation(s)
- D A Tatarskiy
- Institute for Physics of Microstructures RAS, Department of Magnetic Nanostructures, Afonino, Akademicheskaya st.7, Nizhny Novgorod, 603087, Russia; Lobachevsky State University of Nizhny Novgorod, Gagarina ave. 23, Nizhny Novgorod, 603950, Russia.
| | - N S Gusev
- Institute for Physics of Microstructures RAS, Department of Magnetic Nanostructures, Afonino, Akademicheskaya st.7, Nizhny Novgorod, 603087, Russia; Lobachevsky State University of Nizhny Novgorod, Gagarina ave. 23, Nizhny Novgorod, 603950, Russia
| | - S A Gusev
- Institute for Physics of Microstructures RAS, Department of Magnetic Nanostructures, Afonino, Akademicheskaya st.7, Nizhny Novgorod, 603087, Russia
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12
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Du W, Dou K, He Z, Dai Y, Huang B, Ma Y. Bloch-type magnetic skyrmions in two-dimensional lattices. MATERIALS HORIZONS 2023; 10:5071-5078. [PMID: 37668420 DOI: 10.1039/d3mh00868a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/06/2023]
Abstract
Magnetic skyrmions in two-dimensional lattices are a prominent topic of condensed matter physics and materials science. Current research efforts in this field are exclusively constrained to Néel-type and antiskyrmions, while Bloch-type magnetic skyrmions are rarely explored. Here, we report the discovery of Bloch-type magnetic skyrmions in a two-dimensional lattice of MnInP2Te6, using first-principles calculations and Monte-Carlo simulations. Arising from the joint effect of broken inversion symmetry and strong spin-orbit coupling, monolayer MnInP2Te6 presents large Dzyaloshinskii-Moriya interaction. This, along with ferromagnetic exchange interaction and out-of-plane magnetic anisotropy, gives rise to skyrmion physics in monolayer MnInP2Te6, in the absence of a magnetic field. Remarkably, different from all previous works on two-dimensional lattices, the resultant magnetic skyrmions feature Bloch-type magnetism, which is protected by D3 symmetry. Furthermore, Bloch-type magnetic bimerons are also identified in monolayer MnTlP2Te6. The phase diagrams of these Bloch-type topological magnetisms under a magnetic field, temperature and strain are mapped out. Our results greatly enrich the research on magnetic skyrmions in two-dimensional lattices.
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Affiliation(s)
- Wenhui Du
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Shandanan Street 27, Jinan 250100, China.
| | - Kaiying Dou
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Shandanan Street 27, Jinan 250100, China.
| | - Zhonglin He
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Shandanan Street 27, Jinan 250100, China.
| | - Ying Dai
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Shandanan Street 27, Jinan 250100, China.
| | - Baibiao Huang
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Shandanan Street 27, Jinan 250100, China.
| | - Yandong Ma
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Shandanan Street 27, Jinan 250100, China.
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13
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Yu X, Liu Y, Iakoubovskii KV, Nakajima K, Kanazawa N, Nagaosa N, Tokura Y. Realization and Current-Driven Dynamics of Fractional Hopfions and Their Ensembles in a Helimagnet FeGe. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2210646. [PMID: 36871172 DOI: 10.1002/adma.202210646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 02/19/2023] [Indexed: 05/19/2023]
Abstract
3D topological spin textures-hopfions-are predicted in helimagnetic systems but are not experimentally confirmed thus far. By utilizing an external magnetic field and electric current in the present study, 3D topological spin textures are realized, including fractional hopfions with nonzero topological index, in a skyrmion-hosting helimagnet FeGe. Microsecond current pulses are employed to control the dynamics of the expansion and contraction of a bundle composed of a skyrmion and a fractional hopfion, as well as its current-driven Hall motion. This research approach has demonstrated the novel electromagnetic properties of fractional hopfions and their ensembles in helimagnetic systems.
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Affiliation(s)
- Xiuzhen Yu
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
| | - Yizhou Liu
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
| | | | - Kiyomi Nakajima
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
| | - Naoya Kanazawa
- Department of Applied Physics, University of Tokyo, Tokyo, 113-8656, Japan
| | - Naoto Nagaosa
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
- Department of Applied Physics, University of Tokyo, Tokyo, 113-8656, Japan
| | - Yoshinori Tokura
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
- Department of Applied Physics, University of Tokyo, Tokyo, 113-8656, Japan
- Tokyo College, University of Tokyo, Tokyo, 113-8656, Japan
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14
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Li L, Song D, Wang W, Zheng F, Kovács A, Tian M, Dunin-Borkowski RE, Du H. Transformation from Magnetic Soliton to Skyrmion in a Monoaxial Chiral Magnet. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2209798. [PMID: 36573473 DOI: 10.1002/adma.202209798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 12/17/2022] [Indexed: 06/18/2023]
Abstract
Topological spin textures are of great interest for both fundamental physics and applications in spintronics. The Dzyaloshinskii-Moriya interaction underpins the formation of single-twisted magnetic solitons or multi-twisted magnetic skyrmions in magnetic materials with different crystallographic symmetries. However, topological transitions between these two kinds of topological objects have not been verified experimentally. Here, the direct observation of transformations from a chiral soliton lattice (CSL) to magnetic skyrmions in a nanostripe of the monoaxial chiral magnet CrNb3 S6 using Lorentz transmission electron microscopy is reported. In the presence of an external magnetic field, helical spin structures first transform into CSLs and then evolve into isolated elongated magnetic skyrmions. The detailed spin textures of the elongated magnetic skyrmions are resolved using off-axis electron holography and are shown to comprise two merons, which enclose their ends and have unit total topological charge. Magnetic dipolar interactions are shown to play a key role in the magnetic soliton-skyrmion transformation, which depends sensitively on nanostripe width. The findings here, which are consistent with micromagnetic simulations, enrich the family of topological magnetic states and their transitions and promise to further stimulate the exploration of their emergent electromagnetic properties.
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Affiliation(s)
- Long Li
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences, Hefei, Anhui, 230031, P. R. China
- Science Island Branch of Graduate School, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China
| | - Dongsheng Song
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences, Hefei, Anhui, 230031, P. R. China
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Key Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of Education, Institutes of Physical Science and Information Technology, Anhui University, Hefei, Anhui, 230601, P. R. China
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Weiwei Wang
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences, Hefei, Anhui, 230031, P. R. China
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Key Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of Education, Institutes of Physical Science and Information Technology, Anhui University, Hefei, Anhui, 230601, P. R. China
| | - Fengshan Zheng
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425, 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, Guangzhou, 510006, P. R. China
| | - András Kovács
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Mingliang Tian
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences, Hefei, Anhui, 230031, P. R. China
- Science Island Branch of Graduate School, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China
- School of Physics and Optoelectronics Engineering, Anhui University, Hefei, Anhui, 230601, P. R. China
| | - Rafal E Dunin-Borkowski
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Haifeng Du
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences, Hefei, Anhui, 230031, P. R. China
- Science Island Branch of Graduate School, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Key Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of Education, Institutes of Physical Science and Information Technology, Anhui University, Hefei, Anhui, 230601, P. R. China
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15
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Ahrens V, Kiesselbach C, Gnoli L, Giuliano D, Mendisch S, Kiechle M, Riente F, Becherer M. Skyrmions Under Control-FIB Irradiation as a Versatile Tool for Skyrmion Circuits. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2207321. [PMID: 36255142 DOI: 10.1002/adma.202207321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 10/11/2022] [Indexed: 06/16/2023]
Abstract
Magnetic data storage and processing offer certain advances over conventional technologies, amongst which nonvolatility and low power operation are the most outstanding ones. Skyrmions are a promising candidate as a magnetic data carrier. However, the sputtering of skyrmion films and the control of the skyrmion nucleation, motion, and annihilation remains challenging. This work demonstrates that using optimized focused ion beam irradiation and annealing protocols enables the skyrmion phase in W/CoFeB/MgO thin films to be accessed easily. By analyzing ion-beam-engineered skyrmion hosting wires, excited by sub-100 ns current pulses, possibilities to control skyrmion nucleation, guide their motion, and control their annihilation unfold. Overall, the key elements needed to develop extensive skyrmion networks are presented.
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Affiliation(s)
- Valentin Ahrens
- Department of Electrical and Computer Engineering, Technical University of Munich, 85748, Garching, Germany
| | - Clara Kiesselbach
- Department of Electrical and Computer Engineering, Technical University of Munich, 85748, Garching, Germany
| | - Luca Gnoli
- Department of Electronics and Telecommunications, Politecnico di Torino, Torino, 10129, Italy
| | - Domenico Giuliano
- Department of Electronics and Telecommunications, Politecnico di Torino, Torino, 10129, Italy
| | - Simon Mendisch
- Department of Electrical and Computer Engineering, Technical University of Munich, 85748, Garching, Germany
| | - Martina Kiechle
- Department of Electrical and Computer Engineering, Technical University of Munich, 85748, Garching, Germany
| | - Fabrizio Riente
- Department of Electronics and Telecommunications, Politecnico di Torino, Torino, 10129, Italy
| | - Markus Becherer
- Department of Electrical and Computer Engineering, Technical University of Munich, 85748, Garching, Germany
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16
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Yu X, Iakoubovskii KV, Yasin FS, Peng L, Nakajima K, Schneider S, Karube K, Arima T, Taguchi Y, Tokura Y. Real-Space Observations of Three-Dimensional Antiskyrmions and Skyrmion Strings. NANO LETTERS 2022; 22:9358-9364. [PMID: 36383503 PMCID: PMC9756337 DOI: 10.1021/acs.nanolett.2c03142] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 10/26/2022] [Indexed: 06/16/2023]
Abstract
Nanometric topological spin textures, such as skyrmions (Sks) and antiskyrmions (antiSks), have attracted much attention recently. However, most studies have focused on two-dimensional spin textures in films with inherent or synthetic antisymmetric spin-exchange interaction, termed Dzyaloshinskii-Moriya interaction, although three-dimensional (3D) topological spin textures, such as antiSks composed of alternating Bloch- and Néel-type spin spirals, chiral bobbers carrying emergent magnetic monopoles, and deformed Sk strings, are ubiquitous. To elucidate these textures, we have developed a 3D nanometric magnetic imaging technique, tomographic Lorentz transmission electron microscopy (TEM). The approach enables the visualization of the 3D shape of magnetic objects and their 3D vector field mapping. Here we report 3D vector field maps of deformed Sk-strings and antiSk using the technique. This research approach will lead to discoveries and understanding of fertile 3D magnetic structures in a broad class of magnets, providing insight into 3D topological magnetism.
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Affiliation(s)
- Xiuzhen Yu
- RIKEN
Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | | | - Fehmi Sami Yasin
- RIKEN
Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - Licong Peng
- RIKEN
Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - Kiyomi Nakajima
- RIKEN
Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | | | - Kosuke Karube
- RIKEN
Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - Takahisa Arima
- RIKEN
Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
- 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
| | - Yoshinori Tokura
- RIKEN
Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
- Department
of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan
- Tokyo
College, University of Tokyo, Tokyo 113-8656, Japan
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17
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Zheng B, Fu J, Zhu Y, Liang J, She Y, Xiang J, Ma X, Zhang Y, Wang S, Hu G, Zhou Y, Feng Y, Fu Z, Pan N, Lu Y, Zeng H, Gu M, Liu K, Xiang B. Synthesis of stable γ-phase MnS 1-xSe x nanoflakes with inversion symmetry breaking. NANOSCALE 2022; 14:17036-17043. [PMID: 36367106 DOI: 10.1039/d2nr05136b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Inversion symmetry breaking plays a critical role in the formation of magnetic skyrmions. Therefore, for the application of skyrmion-based devices, it is important to develop novel engineering techniques and explore new non-centrosymmetric lattices. In this paper, we report the rational synthesis of stable γ-phase MnS1-xSex (0 ≤ x ≤ 0.45) nanoflakes with an asymmetric distribution of the elemental content, which persists on inversion symmetry breaking. The temperature dependence of resonant second-harmonic generation characterization reveals that a non-centrosymmetric crystal structure exists in our as-grown γ-phase MnS1-xSex with spatial-inversion symmetry breaking. By tuning the parameters of nucleation temperature and growth time, we produced a detailed growth phase diagram, revealing a controllable as-grown structure evolution from γ-phase wurtzite-type to α-phase rock-salt type structure of MnS1-xSex nanoflakes. Our work provides a new playground to explore novel materials that have broken inversion symmetry.
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Affiliation(s)
- Bo Zheng
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Materials Science & Engineering, CAS Key Lab of Materials for Energy Conversion, Anhui Laboratory of Advanced Photon Science and Technology, University of Science and Technology of China, Hefei, China.
| | - Jun Fu
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Laboratory for Physical Science at the Microscale, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, 230026, Hefei, Anhui, People's Republic of China
| | - Yuanmin Zhu
- School of Materials Science and Engineering, Dongguan University of Technology, Dongguan, 523808, China
- Department of Materials Science and Engineering, Southern University of Science and Technology China, Shenzhen, China
| | - Jing Liang
- State Key Laboratory for Mesoscopic Physics, Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing, China
| | - Yongzhi She
- Department of Physics, University of Science and Technology of China, Hefei 230026, China
| | - Junxiang Xiang
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Materials Science & Engineering, CAS Key Lab of Materials for Energy Conversion, Anhui Laboratory of Advanced Photon Science and Technology, University of Science and Technology of China, Hefei, China.
| | - Xiang Ma
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Materials Science & Engineering, CAS Key Lab of Materials for Energy Conversion, Anhui Laboratory of Advanced Photon Science and Technology, University of Science and Technology of China, Hefei, China.
| | - Ying Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Materials Science & Engineering, CAS Key Lab of Materials for Energy Conversion, Anhui Laboratory of Advanced Photon Science and Technology, University of Science and Technology of China, Hefei, China.
| | - Shasha Wang
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Materials Science & Engineering, CAS Key Lab of Materials for Energy Conversion, Anhui Laboratory of Advanced Photon Science and Technology, University of Science and Technology of China, Hefei, China.
| | - Guojing Hu
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Materials Science & Engineering, CAS Key Lab of Materials for Energy Conversion, Anhui Laboratory of Advanced Photon Science and Technology, University of Science and Technology of China, Hefei, China.
| | - Yuehui Zhou
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Materials Science & Engineering, CAS Key Lab of Materials for Energy Conversion, Anhui Laboratory of Advanced Photon Science and Technology, University of Science and Technology of China, Hefei, China.
| | - Yan Feng
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Materials Science & Engineering, CAS Key Lab of Materials for Energy Conversion, Anhui Laboratory of Advanced Photon Science and Technology, University of Science and Technology of China, Hefei, China.
| | - Zhengping Fu
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Materials Science & Engineering, CAS Key Lab of Materials for Energy Conversion, Anhui Laboratory of Advanced Photon Science and Technology, University of Science and Technology of China, Hefei, China.
| | - Nan Pan
- Department of Physics, University of Science and Technology of China, Hefei 230026, China
| | - Yalin Lu
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Materials Science & Engineering, CAS Key Lab of Materials for Energy Conversion, Anhui Laboratory of Advanced Photon Science and Technology, University of Science and Technology of China, Hefei, China.
| | - Hualing Zeng
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Laboratory for Physical Science at the Microscale, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, 230026, Hefei, Anhui, People's Republic of China
| | - Meng Gu
- Department of Materials Science and Engineering, Southern University of Science and Technology China, Shenzhen, China
| | - Kaihui Liu
- State Key Laboratory for Mesoscopic Physics, Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing, China
| | - Bin Xiang
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Materials Science & Engineering, CAS Key Lab of Materials for Energy Conversion, Anhui Laboratory of Advanced Photon Science and Technology, University of Science and Technology of China, Hefei, China.
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18
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Criado JC, Schenk S, Spannowsky M, Hatton PD, Turnbull LA. Simulating anti-skyrmions on a lattice. Sci Rep 2022; 12:19179. [DOI: 10.1038/s41598-022-22043-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 10/07/2022] [Indexed: 11/11/2022] Open
Abstract
AbstractMagnetic skyrmions are meta-stable spin structures that naturally emerge in magnetic materials. While a vast amount of effort has gone into the study of their properties, their counterpart of opposite topological charge, the anti-skyrmion, has not received as much attention. We aim to close this gap by deploying Monte Carlo simulations of spin-lattice systems in order to investigate which interactions support anti-skyrmions, as well as skyrmions of Bloch and Néel type. We find that the combination of ferromagnetic exchange and Dzyaloshinskii–Moriya (DM) interactions is able to stabilize each of the three types, depending on the specific structure of the DM interactions. Considering a three-dimensional spin lattice model, we provide a finite-temperature phase diagram featuring a stable anti-skyrmion lattice phase for a large range of temperatures. In addition, we also shed light on the creation and annihilation processes of these anti-skyrmion tubes and study the effects of the DM interaction strength on their typical size.
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19
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Real-space determination of the isolated magnetic skyrmion deformation under electric current flow. Proc Natl Acad Sci U S A 2022; 119:e2200958119. [PMID: 36191237 PMCID: PMC9564101 DOI: 10.1073/pnas.2200958119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The manipulation and control of electron spins, the fundamental building blocks of magnetic domains and spin textures, are at the core of spintronics. Of particular interest is the effect of the electric current on topological magnetic skyrmions, such as the current-induced deformation of isolated skyrmions. The deformation has consequences ranging from perturbed dynamics to modified packing configurations. In this study, we measured the current-driven real-space deformation of isolated, pinned skyrmions within Co10Zn10 at room temperature. We observed that the skyrmions are surprisingly soft, readily deforming during electric current application into an elliptical shape with a well-defined deformation axis (semimajor axis). We found that this axis rotates unidirectionally toward the current direction irrespective of electric current polarity and that the elliptical deformation reverses back upon current termination. We quantified the average distortion δ, which increased by ∼90% during the largest applied current density |j| = 8.46 ×109 A/m2 when compared with the skyrmion's intrinsic shape ([Formula: see text]). Additionally, we demonstrated an approximately 120% average skyrmion core size expansion during current application, highlighting the skyrmions' inherent topological protection. This evaluation of in situ electric current-induced skyrmion deformation paints a clearer picture of spin-polarized electron-skyrmion interactions and may prove essential in designing spintronic devices.
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20
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Zhang C, Liu C, Zhang S, Zhou B, Guan C, Ma Y, Algaidi H, Zheng D, Li Y, He X, Zhang J, Li P, Hou Z, Yin G, Liu K, Peng Y, Zhang XX. Magnetic Skyrmions with Unconventional Helicity Polarization in a Van Der Waals Ferromagnet. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2204163. [PMID: 35975291 DOI: 10.1002/adma.202204163] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 08/10/2022] [Indexed: 06/15/2023]
Abstract
Skyrmion helicity, which defines the spin swirling direction, is a fundamental parameter that may be utilized to encode data bits in future memory devices. Generally, in centrosymmetric ferromagnets, dipole skyrmions with helicity of -π/2 and π/2 are degenerate in energy, leading to equal populations of both helicities. On the other hand, in chiral materials where the Dzyaloshinskii-Moriya interaction (DMI) prevails and the dipolar interaction is negligible, only a preferred helicity is selected by the type of DMI. However, whether there is a rigid boundary between these two regimes remains an open question. Herein, the observation of dipole skyrmions with unconventional helicity polarization in a van der Waals ferromagnet, Fe5- δ GeTe2 , is reported. Combining magnetometry, Lorentz transmission electron microscopy, electrical transport measurements, and micromagnetic simulations, the short-range superstructures in Fe5- δ GeTe2 resulting in a localized DMI contribution, which breaks the degeneracy of the opposite helicities and leads to the helicity polarization, is demonstrated. Therefore, the helicity feature in Fe5- δ GeTe2 is controlled by both the dipolar interaction and DMI that the former leads to Bloch-type skyrmions with helicity of ±π/2 whereas the latter breaks the helicity degeneracy. This work provides new insights into the skyrmion topology in van der Waals materials.
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Affiliation(s)
- Chenhui Zhang
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Chen Liu
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Senfu Zhang
- Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, School of Physical Science and Technology, Lanzhou University, Lanzhou, 730000, China
| | - Bojian Zhou
- School of Materials and Energy and Electron Microscopy Centre of Lanzhou University, Lanzhou University, Lanzhou, 730000, China
| | - Chaoshuai Guan
- School of Materials and Energy and Electron Microscopy Centre of Lanzhou University, Lanzhou University, Lanzhou, 730000, China
| | - Yinchang Ma
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Hanin Algaidi
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Dongxing Zheng
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Yan Li
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Xin He
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Junwei Zhang
- School of Materials and Energy and Electron Microscopy Centre of Lanzhou University, Lanzhou University, Lanzhou, 730000, China
| | - Peng Li
- State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, 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
| | - Gen Yin
- Physics Department, Georgetown University, Washington, DC, 20057, USA
| | - Kai Liu
- Physics Department, Georgetown University, Washington, DC, 20057, USA
| | - Yong Peng
- School of Materials and Energy and Electron Microscopy Centre of Lanzhou University, Lanzhou University, Lanzhou, 730000, China
| | - Xi-Xiang Zhang
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
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21
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Peng L, Iakoubovskii KV, Karube K, Taguchi Y, Tokura Y, Yu X. Formation and Control of Zero-Field Antiskyrmions in Confining Geometries. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2202950. [PMID: 35978271 PMCID: PMC9534945 DOI: 10.1002/advs.202202950] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 07/22/2022] [Indexed: 06/15/2023]
Abstract
Magnetic skyrmions and antiskyrmions have attracted much interest owing to their topological features and spintronic functionalities. In contrast to skyrmions, the generation of antiskyrmions relies on tunning both the magnitude and direction of the external magnetic field. Here, it is reported that antiskyrmions can be efficiently created via quenching and robustly persist at zero field in the Fe1.9 Ni0.9 Pd0.2 P magnet with the S4 -symmetry. It is demonstrated that well-ordered antiskyrmions form in a square lattice in a confining micrometer-scale square geometry, while the antiskyrmion lattice distorts in triangular, circular, or rotated-square geometry; the distortion depends on the relative configuration between sample edges and the two q-vectors arising from the anisotropic Dzyaloshinskii-Moriya interaction, in good agreement with micromagnetic simulations. It is also characterized transformations from antiskyrmions to skyrmions and nontopological bubbles at different directions and values of external field. These results demonstrate a roadmap for generating and controlling antiskyrmions in a confining geometry.
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Affiliation(s)
- Licong Peng
- RIKEN Center for Emergent Matter ScienceWako351‐0198Japan
| | | | - Kosuke Karube
- RIKEN Center for Emergent Matter ScienceWako351‐0198Japan
| | | | - Yoshinori Tokura
- RIKEN Center for Emergent Matter ScienceWako351‐0198Japan
- Department of Applied PhysicsUniversity of TokyoBunkyo‐ku113‐8656Japan
- Tokyo CollegeUniversity of TokyoBunkyo‐ku113‐8656Japan
| | - Xiuzhen Yu
- RIKEN Center for Emergent Matter ScienceWako351‐0198Japan
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22
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Hayami S. Square skyrmion crystal in centrosymmetric systems with locally inversion-asymmetric layers. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:365802. [PMID: 35738246 DOI: 10.1088/1361-648x/ac7bcb] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Accepted: 06/23/2022] [Indexed: 06/15/2023]
Abstract
We investigate an instability toward a square-lattice formation of magnetic skyrmions in centrosymmetric layered systems. By focusing on a bilayer square-lattice structure with the inversion center at the interlayer bond instead of the atomic site, we numerically examine the stability of the square skyrmion crystal (SkX) based on an effective spin model with the momentum-resolved interaction in the ground state through the simulated annealing. As a result, we find that a layer-dependent staggered Dzyaloshinskii-Moriya (DM) interaction built in the lattice structure becomes the origin of the square SkX in an external magnetic field irrespective of the sign of the interlayer exchange interaction. The obtained square SkX is constituted of the SkXs with different helicities in each layer due to the staggered DM interaction. Furthermore, we show that the interplay between the staggered DM interaction and the interlayer exchange interaction gives rise to a double-Qstate with a uniform component of the scalar chirality in the low-field region. The present results provide another way of stabilizing the square SkX in centrosymmetric magnets, which will be useful to explore further exotic topological spin textures.
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Affiliation(s)
- Satoru Hayami
- Department of Applied Physics, University of Tokyo, Bunkyo, Tokyo 113-8656, Japan
- Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan
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23
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Jena J, Göbel B, Hirosawa T, Díaz SA, Wolf D, Hinokihara T, Kumar V, Mertig I, Felser C, Lubk A, Loss D, Parkin SSP. Observation of fractional spin textures in a Heusler material. Nat Commun 2022; 13:2348. [PMID: 35487903 PMCID: PMC9054820 DOI: 10.1038/s41467-022-29991-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 04/11/2022] [Indexed: 11/09/2022] Open
Abstract
Recently a zoology of non-collinear chiral spin textures has been discovered, most of which, such as skyrmions and antiskyrmions, have integer topological charges. Here we report the experimental real-space observation of the formation and stability of fractional antiskyrmions and fractional elliptical skyrmions in a Heusler material. These fractional objects appear, over a wide range of temperature and magnetic field, at the edges of a sample, whose interior is occupied by an array of nano-objects with integer topological charges, in agreement with our simulations. We explore the evolution of these objects in the presence of magnetic fields and show their interconversion to objects with integer topological charges. This means the topological charge can be varied continuously. These fractional spin textures are not just another type of skyrmion, but are essentially a new state of matter that emerges and lives only at the boundary of a magnetic system. The coexistence of both integer and fractionally charged spin textures in the same material makes the Heusler family of compounds unique for the manipulation of the real-space topology of spin textures and thus an exciting platform for spintronic and magnonic applications. Skyrmions and anti-skyrmions are magnetic textures that have garnered much interest due to their stability. Here, Jena et al demonstrate the existence of fractional spin textures at the edges of Heusler alloy sample, which can have continuous variable topological charges.
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Affiliation(s)
- Jagannath Jena
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120, Halle, Germany
| | - Börge Göbel
- Institute of Physics, Martin Luther University Halle-Wittenberg, 06120, Halle, Germany
| | - Tomoki Hirosawa
- Department of Physics, University of Tokyo, Bunkyo, Tokyo, 113-0033, Japan.,Department of Physics, University of Basel, Klingelberg Strasse 82, 4056, Basel, Switzerland
| | - Sebastián A Díaz
- Department of Physics, University of Basel, Klingelberg Strasse 82, 4056, Basel, Switzerland.,Faculty of Physics, University of Duisburg-Essen, 47057, Duisburg, Germany
| | - Daniel Wolf
- Institute for Solid State Research, IFW Dresden, Helmholtzstrasse 20, 01069, Dresden, Germany
| | - Taichi Hinokihara
- Department of Physics, University of Tokyo, Bunkyo, Tokyo, 113-0033, Japan.,Elements Strategy Initiative Center for Magnetic Materials, National Institute for Materials Science, Tsukuba, Ibaraki, 305-0047, Japan
| | - Vivek Kumar
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Strasse 40, 01187, Dresden, Germany
| | - Ingrid Mertig
- Institute of Physics, Martin Luther University Halle-Wittenberg, 06120, Halle, Germany
| | - Claudia Felser
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Strasse 40, 01187, Dresden, Germany
| | - Axel Lubk
- Institute for Solid State Research, IFW Dresden, Helmholtzstrasse 20, 01069, Dresden, Germany
| | - Daniel Loss
- Department of Physics, University of Basel, Klingelberg Strasse 82, 4056, Basel, Switzerland
| | - Stuart S P Parkin
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120, Halle, Germany.
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24
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Cui Q, Zhu Y, Ga Y, Liang J, Li P, Yu D, Cui P, Yang H. Anisotropic Dzyaloshinskii-Moriya Interaction and Topological Magnetism in Two-Dimensional Magnets Protected by P4̅ m2 Crystal Symmetry. NANO LETTERS 2022; 22:2334-2341. [PMID: 35266723 DOI: 10.1021/acs.nanolett.1c04803] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
As a fundamental magnetic parameter, Dzyaloshinskii-Moriya interaction (DMI), has gained a great deal of attention in the last two decades due to its critical role in formation of magnetic skyrmions. Recent discoveries of two-dimensional (2D) van der Waals (vdW) magnets has also gained a great deal of attention due to appealing physical properties, such as gate tunability, flexibility, and miniaturization. Intensive studies have shown that isotropic DMI stabilizes ferromagnetic (FM) topological spin textures in 2D magnets or their corresponding heterostructures. However, the investigation of anisotropic DMI and antiferromagnetic (AFM) topological spin configurations remains elusive. Here, we propose and demonstrate a family of 2D magnets with P4m2 symmetry-protected anisotropic DMI. More interestingly, various topological spin configurations, including FM/AFM antiskyrmion and AFM vortex-antivortex pair, emerge in this family. These results give a general method to design anisotropic DMI and pave the way toward topological magnetism in 2D materials using crystal symmetry.
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Affiliation(s)
- Qirui Cui
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
- Faculty of Science and Engineering, University of Nottingham Ningbo China, Ningbo 315100, China
| | - Yingmei Zhu
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Yonglong Ga
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Jinghua Liang
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Peng Li
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Dongxing Yu
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Ping Cui
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
- Faculty of Science and Engineering, University of Nottingham Ningbo China, Ningbo 315100, China
| | - Hongxin Yang
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
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25
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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.
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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
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26
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Oyeka EE, Winiarski MJ, Tran TT. Study of Integer Spin S = 1 in the Polar Magnet β-Ni(IO 3) 2. Molecules 2021; 26:molecules26237210. [PMID: 34885793 PMCID: PMC8658994 DOI: 10.3390/molecules26237210] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 11/23/2021] [Accepted: 11/26/2021] [Indexed: 11/16/2022] Open
Abstract
Polar magnetic materials exhibiting appreciable asymmetric exchange interactions can potentially host new topological states of matter such as vortex-like spin textures; however, realizations have been mostly limited to half-integer spins due to rare numbers of integer spin systems with broken spatial inversion lattice symmetries. Here, we studied the structure and magnetic properties of the S = 1 integer spin polar magnet β-Ni(IO3)2 (Ni2+, d8, 3F). We synthesized single crystals and bulk polycrystalline samples of β-Ni(IO3)2 by combining low-temperature chemistry techniques and thermal analysis and characterized its crystal structure and physical properties. Single crystal X-ray and powder X-ray diffraction measurements demonstrated that β-Ni(IO3)2 crystallizes in the noncentrosymmetric polar monoclinic structure with space group P21. The combination of the macroscopic electric polarization driven by the coalignment of the (IO3)− trigonal pyramids along the b axis and the S = 1 state of the Ni2+ cation was chosen to investigate integer spin and lattice dynamics in magnetism. The effective magnetic moment of Ni2+ was extracted from magnetization measurements to be 3.2(1) µB, confirming the S = 1 integer spin state of Ni2+ with some orbital contribution. β-Ni(IO3)2 undergoes a magnetic ordering at T = 3 K at a low magnetic field, μ0H = 0.1 T; the phase transition, nevertheless, is suppressed at a higher field, μ0H = 3 T. An anomaly resembling a phase transition is observed at T ≈ 2.7 K in the Cp/T vs. T plot, which is the approximate temperature of the magnetic phase transition of the material, indicating that the transition is magnetically driven. This work offers a useful route for exploring integer spin noncentrosymmetric materials, broadening the phase space of polar magnet candidates, which can harbor new topological spin physics.
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Affiliation(s)
- Ebube E. Oyeka
- Department of Chemistry, Clemson University, Clemson, SC 29634, USA;
| | - Michał J. Winiarski
- Advanced Materials Center, Faculty of Applied Physics and Mathematics, Gdansk University of Technology, ul. Narutowicza 11/12, 80-233 Gdansk, Poland;
| | - Thao T. Tran
- Department of Chemistry, Clemson University, Clemson, SC 29634, USA;
- Correspondence:
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27
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Oyeka EE, Winiarski MJ, Sorolla Ii M, Taddei KM, Scheie A, Tran TT. Spin and Orbital Effects on Asymmetric Exchange Interaction in Polar Magnets: M(IO 3) 2 (M = Cu and Mn). Inorg Chem 2021; 60:16544-16557. [PMID: 34637293 DOI: 10.1021/acs.inorgchem.1c02432] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Magnetic polar materials feature an astonishing range of physical properties, such as magnetoelectric coupling, chiral spin textures, and related new spin topology physics. This is primarily attributable to their lack of space inversion symmetry in conjunction with unpaired electrons, potentially facilitating an asymmetric Dzyaloshinskii-Moriya (DM) exchange interaction supported by spin-orbital and electron-lattice coupling. However, engineering the appropriate ensemble of coupled degrees of freedom necessary for enhanced DM exchange has remained elusive for polar magnets. Here, we study how spin and orbital components influence the capability of promoting the magnetic interaction by studying two magnetic polar materials, α-Cu(IO3)2 (2D) and Mn(IO3)2 (6S), and connecting their electronic and magnetic properties with their structures. The chemically controlled low-temperature synthesis of these complexes resulted in pure polycrystalline samples, providing a viable pathway to prepare bulk forms of transition-metal iodates. Rietveld refinements of the powder synchrotron X-ray diffraction data reveal that these materials exhibit different crystal structures but crystallize in the same polar and chiral P21 space group, giving rise to an electric polarization along the b-axis direction. The presence and absence of an evident phase transition to a possible topologically distinct state observed in α-Cu(IO3)2 and Mn(IO3)2, respectively, imply the important role of spin-orbit coupling. Neutron diffraction experiments reveal helpful insights into the magnetic ground state of these materials. While the long-wavelength incommensurability of α-Cu(IO3)2 is in harmony with sizable asymmetric DM interaction and low dimensionality of the electronic structure, the commensurate stripe AFM ground state of Mn(IO3)2 is attributed to negligible DM exchange and isotropic orbital overlapping. The work demonstrates connections between combined spin and orbital effects, magnetic coupling dimensionality, and DM exchange, providing a worthwhile approach for tuning asymmetric interaction, which promotes evolution of topologically distinct spin phases.
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Affiliation(s)
- Ebube E Oyeka
- Department of Chemistry, Clemson University, Clemson, South Carolina 29634, United States
| | - Michał J Winiarski
- Faculty of Applied Physics and Mathematics and Advanced Materials Center, Gdansk University of Technology, ul. Narutowicza 11/12, 80-233 Gdansk, Poland
| | - Maurice Sorolla Ii
- Department of Chemical Engineering, University of the Philippines Diliman, Quezon City 1101, Philippines
| | - Keith M Taddei
- Neutron Scattering Division, Oak Ridge National Laboratory, 9500 Spallation Dr, Oak Ridge, Tennessee 37830, United States
| | - Allen Scheie
- Neutron Scattering Division, Oak Ridge National Laboratory, 9500 Spallation Dr, Oak Ridge, Tennessee 37830, United States
| | - Thao T Tran
- Department of Chemistry, Clemson University, Clemson, South Carolina 29634, United States
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28
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Li Z, Su J, Lin SZ, Liu D, Gao Y, Wang S, Wei H, Zhao T, Zhang Y, Cai J, Shen B. Field-free topological behavior in the magnetic domain wall of ferrimagnetic GdFeCo. Nat Commun 2021; 12:5604. [PMID: 34556648 PMCID: PMC8460835 DOI: 10.1038/s41467-021-25926-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 09/09/2021] [Indexed: 11/22/2022] Open
Abstract
Exploring and controlling topological textures such as merons and skyrmions has attracted enormous interests from the perspective of fundamental research and spintronic applications. It has been predicted theoretically and proved experimentally that the lattice form of topological meron-skyrmion transformation can be realized with the requirement of external magnetic fields in chiral ferromagnets. However, such topological transition behavior has yet to be verified in other materials. Here, we report real-space observation of magnetic topology transformation between meron pairs and skyrmions in the localized domain wall of ferrimagnetic GdFeCo films without the need of magnetic fields. The topological transformation in the domain wall of ferrimagnet is introduced by temperature-induced spin reorientation transition (SRT) and the underlying mechanism is revealed by micromagnetic simulations. The convenient electric-controlling topology transformation and driving motion along the confined domain wall is further anticipated, which will enable advanced application in magnetic devices. Merons and Skyrmions, two topological spin-textures, have attracted a lot of interests due to their potential use in information storage. Here, the authors demonstrate the transformation of Meron pairs into Skyrmions without an applied magnetic field within domain walls of GdFeCo films.
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Affiliation(s)
- Zhuolin Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China.,School of Physical Sciences, University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Jian Su
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China.,School of Physical Sciences, University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Shi-Zeng Lin
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Dan Liu
- Department of Physics, Beijing Technology and Business University, 100048, Beijing, China
| | - Yang Gao
- Institute of Advanced Materials, Beijing Normal University, 100875, Beijing, China
| | - Shouguo Wang
- Institute of Advanced Materials, Beijing Normal University, 100875, Beijing, China
| | - Hongxiang Wei
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
| | - Tongyun Zhao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
| | - Ying Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China. .,Songshan Lake Materials Laboratory, Dongguan, 523808, Guangdong, China.
| | - Jianwang Cai
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China.,School of Physical Sciences, University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Baogen Shen
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China.,School of Physical Sciences, University of Chinese Academy of Sciences, 100049, Beijing, China
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29
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Wang B, Wu PK, Bagués Salguero N, Zheng Q, Yan J, Randeria M, McComb DW. Stimulated Nucleation of Skyrmions in a Centrosymmetric Magnet. ACS NANO 2021; 15:13495-13503. [PMID: 34374281 DOI: 10.1021/acsnano.1c04053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Understanding the dynamics of skyrmion nucleation and manipulation is important for applications in spintronic devices. In this contribution, the spin textures at magnetic domain-boundaries stimulated by application of in-plane magnetic fields in a centrosymmetric kagome ferromagnet, Fe3Sn2, with thickness gradient are investigated using Lorentz transmission electron microscopy. Switching of the in-plane magnetic field is shown to induce a reversible transformation from magnetic stripes to skyrmions, or vice versa, at the interface between differently oriented domains. Micromagnetic simulations combined with experiments reveal that the rotatable anisotropy and thickness dependence of the response to the external in-plane field are the critical factors for the skyrmion formation. In addition, it is shown that the helicity of skyrmions can also be controlled using this dynamic process. The results suggest that magnetic materials with rotatable anisotropy are potential skyrmionic systems and provides a different approach for nucleation and manipulation of skyrmions in spintronic devices.
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Affiliation(s)
- Binbin Wang
- Department of Materials Science and Engineering, The Ohio State University, Columbus, Ohio 43212, United States
- Center for Electron Microscopy and Analysis, The Ohio State University, Columbus, Ohio 43212, United States
| | - Po-Kuan Wu
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, United States
| | - Núria Bagués Salguero
- Department of Materials Science and Engineering, The Ohio State University, Columbus, Ohio 43212, United States
- Center for Electron Microscopy and Analysis, The Ohio State University, Columbus, Ohio 43212, United States
| | - Qiang Zheng
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Jiaqiang Yan
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Mohit Randeria
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, United States
| | - David W McComb
- Department of Materials Science and Engineering, The Ohio State University, Columbus, Ohio 43212, United States
- Center for Electron Microscopy and Analysis, The Ohio State University, Columbus, Ohio 43212, United States
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30
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Hayami S, Motome Y. Topological spin crystals by itinerant frustration. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:443001. [PMID: 34343975 DOI: 10.1088/1361-648x/ac1a30] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 08/03/2021] [Indexed: 06/13/2023]
Abstract
Spin textures with nontrivial topology, such as vortices and skyrmions, have attracted attention as a source of unconventional magnetic, transport, and optical phenomena. Recently, a new generation of topological spin textures has been extensively studied in itinerant magnets; in contrast to the conventional ones induced, e.g., by the Dzyaloshinskii-Moriya interaction in noncentrosymmetric systems, they are characterized by extremely short magnetic periods and stable even in centrosymmetric systems. Here we review such new types of topological spin textures with particular emphasis on their stabilization mechanism. Focusing on the interplay between charge and spin degrees of freedom in itinerant electron systems, we show that itinerant frustration, which is the competition among electron-mediated interactions, plays a central role in stabilizing a variety of topological spin crystals including a skyrmion crystal with unconventional high skyrmion number, meron crystals, and hedgehog crystals. We also show that the essential ingredients in the itinerant frustration are represented by bilinear and biquadratic spin interactions in momentum space. This perspective not only provides a unified understanding of the unconventional topological spin crystals but also stimulates further exploration of exotic topological phenomena in itinerant magnets.
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Affiliation(s)
- Satoru Hayami
- Department of Applied Physics, University of Tokyo, Bunkyo, Tokyo 113-8656, Japan
| | - Yukitoshi Motome
- Department of Applied Physics, University of Tokyo, Bunkyo, Tokyo 113-8656, Japan
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31
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Wei W, Tang J, Wu Y, Wang Y, Jiang J, Li J, Soh Y, Xiong Y, Tian M, Du H. Current-Controlled Topological Magnetic Transformations in a Nanostructured Kagome Magnet. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2101610. [PMID: 34224181 DOI: 10.1002/adma.202101610] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 05/14/2021] [Indexed: 06/13/2023]
Abstract
Topological magnetic charge Q is a fundamental parameter that describes the magnetic domains and determines their intriguing electromagnetic properties. The ability to switch Q in a controlled way by electrical methods allows for flexible manipulation of electromagnetic behavior in future spintronic devices. Here, the room-temperature current-controlled topological magnetic transformations between Q = -1 skyrmions and Q = 0 stripes or type-II bubbles in a kagome crystal Fe3 Sn2 are reported. It is shown that reproducible and reversible skyrmion-bubble and skyrmion-stripe transformations can be achieved by tuning the density of nanosecond pulsed current of the order of ≈1010 A m-2 . Further numerical simulations suggest that spin-transfer torque combined with Joule thermal heating effects determine the current-induced topological magnetic transformations.
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Affiliation(s)
- Wensen Wei
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Anhui, Chinese Academy of Sciences, Hefei, 230031, China
| | - Jin Tang
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Anhui, Chinese Academy of Sciences, Hefei, 230031, China
| | - Yaodong Wu
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Anhui, Chinese Academy of Sciences, Hefei, 230031, China
- Key Laboratory for Photoelectric Detection Science and Technology of Education Department of Anhui Province, and School of Physics and Materials Engineering, Hefei Normal University, Hefei, 230601, China
| | - Yihao Wang
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Anhui, Chinese Academy of Sciences, Hefei, 230031, China
| | - Jialiang Jiang
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Anhui, Chinese Academy of Sciences, Hefei, 230031, China
| | - Junbo Li
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Anhui, Chinese Academy of Sciences, Hefei, 230031, China
| | - Yona Soh
- Paul Scherrer Institute, Villigen, 5232, Switzerland
| | - Yimin Xiong
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Anhui, Chinese Academy of Sciences, Hefei, 230031, China
| | - Mingliang Tian
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Anhui, Chinese Academy of Sciences, Hefei, 230031, China
- School of Physics and Materials Science, Anhui University, Hefei, 230601, China
| | - Haifeng Du
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Anhui, Chinese Academy of Sciences, Hefei, 230031, China
- Institutes of Physical Science and Information Technology, Anhui University, Hefei, 230601, China
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32
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Sharma AK, Jena J, Rana KG, Markou A, Meyerheim HL, Mohseni K, Srivastava AK, Kostanoskiy I, Felser C, Parkin SSP. Nanoscale Noncollinear Spin Textures in Thin Films of a D 2d Heusler Compound. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2101323. [PMID: 34218470 DOI: 10.1002/adma.202101323] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Indexed: 06/13/2023]
Abstract
Magnetic nano-objects, namely antiskyrmions and Bloch skyrmions, have been found to coexist in single-crystalline lamellae formed from bulk crystals of inverse tetragonal Heusler compounds with D2d symmetry. Here evidence is shown for magnetic nano-objects in epitaxial thin films of Mn2 RhSn formed by magnetron sputtering. These nano-objects exhibit a wide range of sizes with stability with respect to magnetic field and temperature that is similar to single-crystalline lamellae. However, the nano-objects do not form well-defined arrays, nor is any evidence found for helical spin textures. This is speculated to likely be a consequence of the poorer homogeneity of chemical ordering in the thin films. However, evidence is found for elliptically distorted nano-objects along perpendicular crystallographic directions within the epitaxial films, which is consistent with elliptical Bloch skyrmions observed in single-crystalline lamellae. Thus, these measurements provide strong evidence for the formation of noncollinear spin textures in thin films of Mn2 RhSn. Using these films, it is shown that individual nano-objects can be deleted using a local magnetic field from a magnetic tip and collections of nano-objects can be similarly written. These observations suggest a path toward the use of these objects in thin films with D2d symmetry as magnetic memory elements.
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Affiliation(s)
- Ankit K Sharma
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120, Halle, Germany
| | - Jagannath Jena
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120, Halle, Germany
| | - Kumari Gaurav Rana
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120, Halle, Germany
| | - Anastasios Markou
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, 01187, Dresden, Germany
| | - Holger L Meyerheim
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120, Halle, Germany
| | - Katayoon Mohseni
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120, Halle, Germany
| | - Abhay K Srivastava
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120, Halle, Germany
| | - Ilya Kostanoskiy
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120, Halle, Germany
| | - Claudia Felser
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, 01187, Dresden, Germany
| | - Stuart S P Parkin
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120, Halle, Germany
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33
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Amoroso D, Barone P, Picozzi S. Interplay between Single-Ion and Two-Ion Anisotropies in Frustrated 2D Semiconductors and Tuning of Magnetic Structures Topology. NANOMATERIALS 2021; 11:nano11081873. [PMID: 34443704 PMCID: PMC8397980 DOI: 10.3390/nano11081873] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 07/15/2021] [Accepted: 07/16/2021] [Indexed: 01/14/2023]
Abstract
The effects of competing magnetic interactions in stabilizing different spin configurations are drawing renewed attention in order to unveil emerging topological spin textures and to highlight microscopic mechanisms leading to their stabilization. The possible key role of the two-site exchange anisotropy in selecting specific helicity and vorticity of skyrmionic lattices has only recently been proposed. In this work, we explore the phase diagram of a frustrated localized magnet characterized by a two-dimensional centrosymmetric triangular lattice, focusing on the interplay between the two-ion anisotropy and the single-ion anisotropy. The effects of an external magnetic field applied perpendicularly to the magnetic layer, are also investigated. By means of Monte Carlo simulations, we find an abundance of different spin configurations, going from trivial to high-order Q skyrmionic and meronic lattices. In closer detail, we find that a dominant role is played by the two-ion over the single-ion anisotropy in determining the planar spin texture; the strength and the sign of single ion anisotropy, together with the magnitude of the magnetic field, tune the perpendicular spin components, mostly affecting the polarity (and, in turn, the topology) of the spin texture. Our analysis confirms the crucial role of the anisotropic symmetric exchange in systems with dominant short-range interactions; at the same time, we predict a rich variety of complex magnetic textures, which may arise from a fine tuning of competing anisotropic mechanisms.
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Affiliation(s)
- Danila Amoroso
- Consiglio Nazionale delle Ricerche CNR-SPIN, c/o Università degli Studi “G. D’Annunzio”, I-66100 Chieti, Italy;
- Correspondence:
| | - Paolo Barone
- Consiglio Nazionale delle Ricerche CNR-SPIN, Area della Ricerca di Tor Vergata, Via del Fosso del Cavaliere 100, I-00133 Rome, Italy;
| | - Silvia Picozzi
- Consiglio Nazionale delle Ricerche CNR-SPIN, c/o Università degli Studi “G. D’Annunzio”, I-66100 Chieti, Italy;
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34
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Heigl M, Koraltan S, Vaňatka M, Kraft R, Abert C, Vogler C, Semisalova A, Che P, Ullrich A, Schmidt T, Hintermayr J, Grundler D, Farle M, Urbánek M, Suess D, Albrecht M. Dipolar-stabilized first and second-order antiskyrmions in ferrimagnetic multilayers. Nat Commun 2021; 12:2611. [PMID: 33972515 PMCID: PMC8110839 DOI: 10.1038/s41467-021-22600-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 03/15/2021] [Indexed: 02/03/2023] Open
Abstract
Skyrmions and antiskyrmions are topologically protected spin structures with opposite vorticities. Particularly in coexisting phases, these two types of magnetic quasi-particles may show fascinating physics and potential for spintronic devices. While skyrmions are observed in a wide range of materials, until now antiskyrmions were exclusive to materials with D2d symmetry. In this work, we show first and second-order antiskyrmions stabilized by magnetic dipole-dipole interaction in Fe/Gd-based multilayers. We modify the magnetic properties of the multilayers by Ir insertion layers. Using Lorentz transmission electron microscopy imaging, we observe coexisting antiskyrmions, Bloch skyrmions, and type-2 bubbles and determine the range of material properties and magnetic fields where the different spin objects form and dissipate. We perform micromagnetic simulations to obtain more insight into the studied system and conclude that the reduction of saturation magnetization and uniaxial magnetic anisotropy leads to the existence of this zoo of different spin objects and that they are primarily stabilized by dipolar interaction.
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Affiliation(s)
- Michael Heigl
- Institute of Physics, University of Augsburg, Augsburg, Germany.
| | - Sabri Koraltan
- Faculty of Physics, University of Vienna, Vienna, Austria
| | - Marek Vaňatka
- CEITEC BUT, Brno University of Technology, Brno, Czech Republic
| | - Robert Kraft
- Faculty of Physics, University of Vienna, Vienna, Austria
| | - Claas Abert
- Faculty of Physics, University of Vienna, Vienna, Austria
- Research Platform MMM Mathematics - Magnetism - Materials, University of Vienna, Vienna, Austria
| | | | - Anna Semisalova
- Center for Nanointegration and Faculty of Physics, University of Duisburg-Essen, Duisburg, Germany
| | - Ping Che
- Laboratory of Nanoscale Magnetic Materials and Magnonics, Institute of Materials (IMX), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Aladin Ullrich
- Institute of Physics, University of Augsburg, Augsburg, Germany
| | - Timo Schmidt
- Institute of Physics, University of Augsburg, Augsburg, Germany
| | | | - Dirk Grundler
- Laboratory of Nanoscale Magnetic Materials and Magnonics, Institute of Materials (IMX), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Institute of Microengineering (IMT), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Michael Farle
- Center for Nanointegration and Faculty of Physics, University of Duisburg-Essen, Duisburg, Germany
| | - Michal Urbánek
- CEITEC BUT, Brno University of Technology, Brno, Czech Republic
| | - Dieter Suess
- Faculty of Physics, University of Vienna, Vienna, Austria
- Research Platform MMM Mathematics - Magnetism - Materials, University of Vienna, Vienna, Austria
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35
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Elastocaloric-effect-induced adiabatic magnetization in paramagnetic salts due to the mutual interactions. Sci Rep 2021; 11:9431. [PMID: 33941810 PMCID: PMC8093207 DOI: 10.1038/s41598-021-88778-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 04/16/2021] [Indexed: 11/08/2022] Open
Abstract
The temperature change under adiabatic stress, i.e., the elastocaloric effect, is a well-understood phenomenon and of particular interest due to its potential application in alternative ways for refrigeration. Here, we demonstrate that in the regime of low-temperatures (a few mK) real paramagnets can be magnetized when compressed adiabatically without applied magnetic field. Such adiabatic magnetization is a genuine many-body problem, stemming from the inherent dipolar mutual interactions between adjacent magnetic moments. We showcase experimental setups to carry out adiabatic magnetization and thus to access such a subtle effect. Perspectives of further investigations by controlling the mutual interactions in Bose-Einstein condensates in magnetic insulators and dipolar spin-ice systems via the adiabatic increase of temperature are also presented. Yet, we discuss the connection between the elastic Grüneisen parameter and the shift on the critical temperature of second-order phase transitions under adiabatic stress, as well as its connection with the Ehrenfest relation.
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36
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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.
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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
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37
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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.
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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
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Karube K, Peng L, Masell J, Yu X, Kagawa F, Tokura Y, Taguchi Y. Room-temperature antiskyrmions and sawtooth surface textures in a non-centrosymmetric magnet with S 4 symmetry. NATURE MATERIALS 2021; 20:335-340. [PMID: 33495630 DOI: 10.1038/s41563-020-00898-w] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 12/02/2020] [Indexed: 06/12/2023]
Abstract
Topological spin textures have attracted much attention both for fundamental physics and spintronics applications. Among them, antiskyrmions possess a unique spin configuration with Bloch-type and Néel-type domain walls owing to anisotropic Dzyaloshinskii-Moriya interaction in the non-centrosymmetric crystal structure. However, antiskyrmions have thus far only been observed in a few Heusler compounds with D2d symmetry. Here we report a new material, Fe1.9Ni0.9Pd0.2P, in a different symmetry class (S4), in which antiskyrmions exist over a wide temperature range that includes room temperature, and transform into skyrmions on changing magnetic field and lamella thickness. The periodicity of magnetic textures greatly depends on the crystal thickness, and domains with anisotropic sawtooth fractals were observed at the surface of thick crystals and attributed to the interplay between the dipolar interaction and the Dzyaloshinskii-Moriya interaction as governed by crystal symmetry. Our findings provide an arena in which to study antiskyrmions, and should stimulate further research on topological spin textures and their applications.
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Affiliation(s)
- Kosuke Karube
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Japan.
| | - Licong Peng
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Japan
| | - Jan Masell
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Japan
| | - Xiuzhen Yu
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Japan
| | - Fumitaka Kagawa
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Japan
- Department of Applied Physics, University of Tokyo, Bunkyo-ku, Japan
| | - Yoshinori Tokura
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Japan
- Department of Applied Physics, University of Tokyo, Bunkyo-ku, Japan
- Tokyo College, University of Tokyo, Bunkyo-ku, Japan
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39
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Jena J, Göbel B, Kumar V, Mertig I, Felser C, Parkin S. Evolution and competition between chiral spin textures in nanostripes with D 2d symmetry. SCIENCE ADVANCES 2020; 6:6/49/eabc0723. [PMID: 33277247 PMCID: PMC7821896 DOI: 10.1126/sciadv.abc0723] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Accepted: 10/20/2020] [Indexed: 06/12/2023]
Abstract
Chiral spin textures are of considerable interest for applications in spintronics. It has recently been shown that magnetic materials with D 2d symmetry can sustain several distinct spin textures. Here, we show, using Lorentz transmission electron microscopy, that single and double chains of antiskyrmions can be generated at room temperature in nanostripes less than 0.5 μm in width formed from the D 2d Heusler compound Mn1.4Pt0.9Pd0.1Sn. Typically, truncated helical spin textures are formed in low magnetic fields, whose edges are terminated by half antiskyrmions. These evolve into chains of antiskyrmions with increasing magnetic field. Single chains of these objects are located in the middle of the nanostripes even when the stripes are much wider than the antiskyrmions. Moreover, the chains can even include elliptical Bloch skyrmions depending on details of the applied magnetic field history. These findings make D 2d materials special and highly interesting for applications such as magnetic racetrack memory storage devices.
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Affiliation(s)
- Jagannath Jena
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle, Germany
| | - Börge Göbel
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle, Germany
- Institute of Physics, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
| | - Vivek Kumar
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Strasse 40, 01187 Dresden, Germany
| | - Ingrid Mertig
- Institute of Physics, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
| | - Claudia Felser
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Strasse 40, 01187 Dresden, Germany
| | - Stuart Parkin
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle, Germany.
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40
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Spontaneous skyrmionic lattice from anisotropic symmetric exchange in a Ni-halide monolayer. Nat Commun 2020; 11:5784. [PMID: 33188198 PMCID: PMC7666143 DOI: 10.1038/s41467-020-19535-w] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 10/02/2020] [Indexed: 11/09/2022] Open
Abstract
Topological spin structures, such as magnetic skyrmions, hold great promises for data storage applications, thanks to their inherent stability. In most cases, skyrmions are stabilized by magnetic fields in non-centrosymmetric systems displaying the chiral Dzyaloshinskii-Moriya exchange interaction, while spontaneous skyrmion lattices have been reported in centrosymmetric itinerant magnets with long-range interactions. Here, a spontaneous anti-biskyrmion lattice with unique topology and chirality is predicted in the monolayer of a semiconducting and centrosymmetric metal halide, NiI2. Our first-principles and Monte Carlo simulations reveal that the anisotropies of the short-range symmetric exchange, when combined with magnetic frustration, can lead to an emergent chiral interaction that is responsible for the predicted topological spin structures. The proposed mechanism finds a prototypical manifestation in two-dimensional magnets, thus broadening the class of materials that can host spontaneous skyrmionic states.
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41
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Yasin FS, Peng L, Takagi R, Kanazawa N, Seki S, Tokura Y, Yu X. Bloch Lines Constituting Antiskyrmions Captured via Differential Phase Contrast. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2004206. [PMID: 33043519 DOI: 10.1002/adma.202004206] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 08/11/2020] [Indexed: 06/11/2023]
Abstract
Much scientific capital has been directed toward exotic magnetic spin textures called Bloch lines, that is, Néel-type line boundaries within domain walls, because their geometry promises high-density magnetic storage. While predicted to arise in high-anisotropy magnets, bulk soft magnets, and thin films with in-plane magnetization, Bloch lines also constitute magnetic antiskyrmions, that is, topological antiparticles of skyrmions. Most domain walls occur as Bloch-type or Néel-type, in which the magnetization rotates parallel or perpendicular to the domain wall across its profile, respectively. The Bloch lines' Néel-type rotation and their minute size make them difficult to directly measure. This work utilizes differential phase contrast (DPC) scanning transmission electron microscopy (STEM) to measure the in-plane magnetization of Bloch lines within antiskyrmions emergent in a non-centrosymmetric Heusler magnet with D2d symmetry, Mn1.4 Pt0.9 Pd0.1 Sn, in addition to Bloch-type skyrmions in an FeGe magnet with B20-type crystal structure to benchmark the DPC technique. Both in-focus measurement and identification of Bloch lines at the antiskyrmion's corners are provided.
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Affiliation(s)
- Fehmi S Yasin
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
| | - Licong Peng
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
| | - Rina Takagi
- Institute of Engineering Innovation, The University of Tokyo, Tokyo, 113-0032, Japan
- Department of Applied Physics, The University of Tokyo, Tokyo, 113-8656, Japan
| | - Naoya Kanazawa
- Department of Applied Physics, The University of Tokyo, Tokyo, 113-8656, Japan
| | - Shinichiro Seki
- Institute of Engineering Innovation, The University of Tokyo, Tokyo, 113-0032, Japan
- 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
- Tokyo College, University of Tokyo, Tokyo, 113-8656, Japan
| | - Xiuzhen Yu
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
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42
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Yu X, Masell J, Yasin FS, Karube K, Kanazawa N, Nakajima K, Nagai T, Kimoto K, Koshibae W, Taguchi Y, Nagaosa N, Tokura Y. Real-Space Observation of Topological Defects in Extended Skyrmion-Strings. NANO LETTERS 2020; 20:7313-7320. [PMID: 32969656 DOI: 10.1021/acs.nanolett.0c02708] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Exotic topological spin textures such as emergent magnetic monopole/anti-monopoles (hedgehog/anti-hedgehog) in the metastable extended skyrmion-strings attract much attention to the fundamental physics owing to their novel electromagnetic properties. However, the direct imaging of such spin textures is lacking. Here, we report the real-space observation of emergent magnetic monopoles involved in extended skyrmion-strings by Lorentz transmission electron microscopy (TEM) in combination with micromagnetic simulations. The in-plane extended skyrmion-strings are observed directly by Lorentz TEM to accompany the topological hedgehog-like defect, where the skyrmion-string terminates or merges with another skyrmion-string, as well as the surface-related defects where skyrmion-string bends 90° and ends on the surface. We also demonstrate the transformation of a metastabilized lattice of out-of-plane short skyrmion-strings into an in-plane array of extended skyrmion-strings by tuning the magnitude of oblique fields in a room-temperature helimagnet, revealing the stability of such topological spin textures and the possibility to control them.
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Affiliation(s)
- Xiuzhen Yu
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
| | - Jan Masell
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
| | - Fehmi S Yasin
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
| | - Kosuke Karube
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
| | - Naoya Kanazawa
- Department of Applied Physics, University of Tokyo, Tokyo, 113-8656, Japan
| | - Kiyomi Nakajima
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
| | - Takuro Nagai
- Research Center for Advanced Measurement and Characterization, National Institute for Materials Science, Tsukuba, 305-0044, Japan
| | - Koji Kimoto
- Research Center for Advanced Measurement and Characterization, National Institute for Materials Science, Tsukuba, 305-0044, Japan
| | - Wataru Koshibae
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
| | - Yasujiro Taguchi
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
| | - Naoto Nagaosa
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
- Department of Applied Physics, University of Tokyo, Tokyo, 113-8656, Japan
| | - Yoshinori Tokura
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
- Department of Applied Physics, University of Tokyo, Tokyo, 113-8656, Japan
- Tokyo College, University of Tokyo, Tokyo, 113-8656, Japan
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43
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Xu C, Chen P, Tan H, Yang Y, Xiang H, Bellaiche L. Electric-Field Switching of Magnetic Topological Charge in Type-I Multiferroics. PHYSICAL REVIEW LETTERS 2020; 125:037203. [PMID: 32745421 DOI: 10.1103/physrevlett.125.037203] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 06/17/2020] [Indexed: 06/11/2023]
Abstract
Applying electric field to control magnetic properties is a very efficient way for spintronics devices. However, the control of magnetic characteristics by electric fields is not straightforward, due to the time-reversal symmetry of magnetism versus spatial inversion symmetry of electricity. Such fundamental difficulty makes it challenging to modify the topology of magnetic skyrmionic states with electric field. Here, we propose a novel mechanism that realizes the electric-field (E) switching of magnetic topological charge (Q) in a controllable and reversible fashion, through the mediation of electric polarization (P) and Dzyaloshinskii-Moriya interaction (D). Such a mechanism is coined here EPDQ. Its validity is demonstrated in a multiferroic VOI_{2} monolayer, which is predicted to host magnetic bimerons. The change in magnetic anisotropy is found to play a crucial role in realizing the EPDQ process and its microscopic origin is discussed. Our study thus provides a new approach toward the highly desired electric-field control of magnetism.
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Affiliation(s)
- Changsong Xu
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - Peng Chen
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - Hengxin Tan
- Max Planck-Institute of Microstructure Physics, Weinberg 2, 06120 Halle (Saale), Germany
| | - Yurong Yang
- National Laboratory of Solid State Microstructures and Collaborative Innovation Center of Advanced Microstructures, Department of Materials Science and Engineering, Nanjing University, Nanjing 210093, China
- Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing 210093, China
| | - Hongjun Xiang
- Key Laboratory of Computational Physical Sciences (Ministry of Education), State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai 200433, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China
- Shanghai Qi Zhi Institute, Shanghai 200232, China
| | - L Bellaiche
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
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Ma T, Sharma AK, Saha R, Srivastava AK, Werner P, Vir P, Kumar V, Felser C, Parkin SSP. Tunable Magnetic Antiskyrmion Size and Helical Period from Nanometers to Micrometers in a D 2d Heusler Compound. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2002043. [PMID: 32484269 DOI: 10.1002/adma.202002043] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 04/27/2020] [Indexed: 06/11/2023]
Abstract
Skyrmions and antiskyrmions are magnetic nano-objects with distinct chiral, noncollinear spin textures that are found in various magnetic systems with crystal symmetries that give rise to specific Dzyaloshinskii-Moriya exchange vectors. These magnetic nano-objects are associated with closely related helical spin textures that can form in the same material. The skyrmion size and the period of the helix are generally considered as being determined, in large part, by the ratio of the magnitude of the Heisenberg to that of the Dzyaloshinskii-Moriya exchange interaction. In this work, it is shown by real-space magnetic imaging that the helix period λ and the size of the antiskyrmion daSk in the D2d compound Mn1.4 PtSn can be systematically tuned by more than an order of magnitude from ≈100 nm to more than 1.1 µm by varying the thickness of the lamella in which they are observed. The chiral spin texture is verified to be preserved even up to micrometer-thick layers. This extreme size tunability is shown to arise from long-range magnetodipolar interactions, which typically play a much less important role for B20 skyrmions. This tunability in size makes antiskyrmions very attractive for technological applications.
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Affiliation(s)
- Tianping Ma
- Max Planck Institute of Microstructure Physics, Weinberg 2, Halle (Saale), D-06120, Germany
- Institute of Physics, Martin Luther University, Halle-Wittenberg, Halle (Saale), D-06120, Germany
| | - Ankit K Sharma
- Max Planck Institute of Microstructure Physics, Weinberg 2, Halle (Saale), D-06120, Germany
- Institute of Physics, Martin Luther University, Halle-Wittenberg, Halle (Saale), D-06120, Germany
| | - Rana Saha
- Max Planck Institute of Microstructure Physics, Weinberg 2, Halle (Saale), D-06120, Germany
| | - Abhay K Srivastava
- Max Planck Institute of Microstructure Physics, Weinberg 2, Halle (Saale), D-06120, Germany
- Institute of Physics, Martin Luther University, Halle-Wittenberg, Halle (Saale), D-06120, Germany
| | - Peter Werner
- Max Planck Institute of Microstructure Physics, Weinberg 2, Halle (Saale), D-06120, Germany
| | - Praveen Vir
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straβe 40, Dresden, 01187, Germany
| | - Vivek Kumar
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straβe 40, Dresden, 01187, Germany
| | - Claudia Felser
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straβe 40, Dresden, 01187, Germany
| | - Stuart S P Parkin
- Max Planck Institute of Microstructure Physics, Weinberg 2, Halle (Saale), D-06120, Germany
- Institute of Physics, Martin Luther University, Halle-Wittenberg, Halle (Saale), D-06120, Germany
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