1
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Li Z, Yin Q, Lv W, Shen J, Wang S, Zhao T, Cai J, Lei H, Lin SZ, Zhang Y, Shen B. Electron-Assisted Generation and Straight Movement of Skyrmion Bubble in Kagome TbMn 6Sn 6. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2309538. [PMID: 38366361 DOI: 10.1002/adma.202309538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 12/31/2023] [Indexed: 02/18/2024]
Abstract
Topological magnetic textures are promising candidates as binary data units for the next-generation memory device. The precise generation and convenient control of nontrivial spin topology at zero field near room temperature endows the critical advantages in skyrmionic devices but is not simultaneously integrated into one material. Here, in the Kagome plane of quantum TbMn6Sn6, the expedient generation of the skyrmion bubbles in versatile forms of lattice, chain, and isolated one by converging the electron beam, where the electron intensity gradient contributes to the dynamic generation from local anisotropy variation near spin reorientation transition (SRT) is reported. Encouragingly, by utilizing the dynamic shift of the SRT domain interface, the straight movement is actualized with the skyrmion bubble slave to the SRT domain interface forming an elastic composite object, avoiding the usual deflection from the skyrmion Hall effect. The critical contribution of the SRT domain interface via conveniently electron-assisted heating is further theoretically validated in micromagnetic simulation, highlighting the compatible application possibility in advanced devices.
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Affiliation(s)
- Zhuolin Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
| | - Qiangwei Yin
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & MicroNano Devices, Renmin University of China, Beijing, 100872, China
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing, 100872, China
| | - Wenxin Lv
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & MicroNano Devices, Renmin University of China, Beijing, 100872, China
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing, 100872, China
| | - Jun Shen
- Department of Energy and Power Engineering, School of Mechanical Engineering, Beijing Institute of Technology, Beijing, 100081, China
| | - Shouguo Wang
- Anhui Key Laboratory of Magnetic Functional Materials and Devices, School of Materials Science and Engineering, Anhui University, Hefei, 230601, China
| | - Tongyun Zhao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
| | - Jianwang Cai
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
| | - Hechang Lei
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & MicroNano Devices, Renmin University of China, Beijing, 100872, China
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing, 100872, China
| | - Shi-Zeng Lin
- Theoretical Division and Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico, 87545, USA
| | - Ying Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
- Open Access Research Infrastrucure, Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Baogen Shen
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
- Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang, 315201, China
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2
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Kato YD, Okamura Y, Hirschberger M, Tokura Y, Takahashi Y. Topological magneto-optical effect from skyrmion lattice. Nat Commun 2023; 14:5416. [PMID: 37669971 PMCID: PMC10480175 DOI: 10.1038/s41467-023-41203-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 08/23/2023] [Indexed: 09/07/2023] Open
Abstract
The magnetic skyrmion is a spin-swirling topological object characterized by its nontrivial winding number, holding potential for next-generation spintronic devices. While optical readout has become increasingly important towards the high integration and ultrafast operation of those devices, the optical response of skyrmions has remained elusive. Here, we show the magneto-optical Kerr effect (MOKE) induced by the skyrmion formation, i.e., topological MOKE, in Gd2PdSi3. The significantly enhanced optical rotation found in the skyrmion phase demonstrates the emergence of topological MOKE, exemplifying the light-skyrmion interaction arising from the emergent gauge field. This gauge field in momentum space causes a dramatic reconstruction of the electronic band structure, giving rise to magneto-optical activity ranging up to the sub-eV region. The present findings pave a way for photonic technology based on skyrmionics.
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Affiliation(s)
- Yoshihiro D Kato
- Department of Applied Physics and Quantum Phase Electronics Center, University of Tokyo, Tokyo, 113-8656, Japan
| | - Yoshihiro Okamura
- Department of Applied Physics and Quantum Phase Electronics Center, University of Tokyo, Tokyo, 113-8656, Japan.
| | - Max Hirschberger
- Department of Applied Physics and Quantum Phase Electronics Center, University of Tokyo, Tokyo, 113-8656, Japan
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
| | - Yoshinori Tokura
- Department of Applied Physics and Quantum Phase Electronics Center, 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
| | - Youtarou Takahashi
- Department of Applied Physics and Quantum Phase Electronics Center, University of Tokyo, Tokyo, 113-8656, Japan.
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan.
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3
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Zhang H, Wang Z, Dahlbom D, Barros K, Batista CD. CP 2 skyrmions and skyrmion crystals in realistic quantum magnets. Nat Commun 2023; 14:3626. [PMID: 37336881 DOI: 10.1038/s41467-023-39232-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 06/05/2023] [Indexed: 06/21/2023] Open
Abstract
Magnetic skyrmions are nanoscale topological textures that have been recently observed in different families of quantum magnets. These objects are called CP1 skyrmions because they are built from dipoles-the target manifold is the 1D complex projective space, CP1 ≅ S2. Here we report the emergence of magnetic CP2 skyrmions in a realistic spin-1 model, which includes both dipole and quadrupole moments. Unlike CP1 skyrmions, CP2 skyrmions can also arise as metastable textures of quantum paramagnets, opening a new road to discover emergent topological solitons in non-magnetic materials. The quantum phase diagram of the spin-1 model also includes magnetic field-induced CP2 skyrmion crystals that can be detected with regular momentum- (diffraction) and real-space (Lorentz transmission electron microscopy) experimental techniques.
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Affiliation(s)
- Hao Zhang
- Department of Physics and Astronomy, The University of Tennessee, Knoxville, TN, 37996, USA.
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
- Theoretical Division and CNLS, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA.
| | - Zhentao Wang
- Department of Physics and Astronomy, The University of Tennessee, Knoxville, TN, 37996, USA
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, 55455, USA
- Center for Correlated Matter and School of Physics, Zhejiang University, Hangzhou, 310058, China
| | - David Dahlbom
- Department of Physics and Astronomy, The University of Tennessee, Knoxville, TN, 37996, USA
| | - Kipton Barros
- Theoretical Division and CNLS, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Cristian D Batista
- Department of Physics and Astronomy, The University of Tennessee, Knoxville, TN, 37996, USA.
- Quantum Condensed Matter Division and Shull-Wollan Center, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
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4
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Li Z, Yin Q, Jiang Y, Zhu Z, Gao Y, Wang S, Shen J, Zhao T, Cai J, Lei H, Lin SZ, Zhang Y, Shen B. Discovery of Topological Magnetic Textures near Room Temperature in Quantum Magnet TbMn 6 Sn 6. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2211164. [PMID: 36856016 DOI: 10.1002/adma.202211164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 02/19/2023] [Indexed: 05/19/2023]
Abstract
The study of topology in quantum materials has fundamentally advanced the understanding in condensed matter physics and potential applications in next-generation quantum information technology. Recently, the discovery of a topological Chern phase in the spin-orbit-coupled Kagome lattice TbMn6 Sn6 has attracted considerable interest. Whereas these phenomena highlight the contribution of momentum space Berry curvature and Chern gap on the electronic transport properties, less is known about the intrinsic real space magnetic texture, which is crucial for understanding the electronic properties and further exploring the unique quantum behavior. Here, the stabilization of topological magnetic skyrmions in TbMn6 Sn6 using Lorentz transmission electron microscopy near room temperature, where the spins experience full spin reorientation transition between the a- and c-axes, is directly observed. An effective spin Hamiltonian based on the Ginzburg-Landau theory is constructed and micromagnetic simulation is performed to clarify the critical role of Ruderman-Kittel-Kasuya-Yosida interaction on the stabilization of skyrmion lattice. These results not only uncover nontrivial spin topological texture in TbMn6 Sn6 , but also provide a solid basis to study its interplay with electronic topology.
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Affiliation(s)
- Zhuolin Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
| | - Qiangwei Yin
- Laboratory for Neutron Scattering, Beijing Key Laboratory of Opto-Electronic Functional Materials & Micro-Nano Devices, Department of Physics, Renmin University of China, Beijing, 100872, China
| | - Yi Jiang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
| | - ZhaoZhao Zhu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Yang Gao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
- School of Materials Science and Engineering, Anhui University, Hefei, 230601, China
| | - Shouguo Wang
- School of Materials Science and Engineering, Anhui University, Hefei, 230601, China
| | - Jun Shen
- Department of Energy and Power Engineering, School of Mechanical Engineering, Beijing Institute of Technology, Beijing, 100081, China
| | - Tongyun Zhao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
| | - Jianwang Cai
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
| | - Hechang Lei
- Laboratory for Neutron Scattering, Beijing Key Laboratory of Opto-Electronic Functional Materials & Micro-Nano Devices, Department of Physics, Renmin University of China, Beijing, 100872, China
| | - Shi-Zeng Lin
- Theoretical Division and Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Ying Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Baogen Shen
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
- Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang, 315201, China
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5
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Paddison JAM, Rai BK, May AF, Calder S, Stone MB, Frontzek MD, Christianson AD. Magnetic Interactions of the Centrosymmetric Skyrmion Material Gd_{2}PdSi_{3}. PHYSICAL REVIEW LETTERS 2022; 129:137202. [PMID: 36206423 DOI: 10.1103/physrevlett.129.137202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 07/12/2022] [Accepted: 09/08/2022] [Indexed: 06/16/2023]
Abstract
The experimental realization of magnetic skyrmion crystals in centrosymmetric materials has been driven by theoretical understanding of how a delicate balance of anisotropy and frustration can stabilize topological spin structures in applied magnetic fields. Recently, the centrosymmetric material Gd_{2}PdSi_{3} was shown to host a field-induced skyrmion crystal, but the skyrmion stabilization mechanism remains unclear. Here, we employ neutron-scattering measurements on an isotopically enriched polycrystalline Gd_{2}PdSi_{3} sample to quantify the interactions that drive skyrmion formation. Our analysis reveals spatially extended interactions in triangular planes, and large ferromagnetic interplanar magnetic interactions that are modulated by the Pd/Si superstructure. The skyrmion crystal emerges from a zero-field helical magnetic order with magnetic moments perpendicular to the magnetic propagation vector, indicating that the magnetic dipolar interaction plays a significant role. Our experimental results establish an interaction space that can promote skyrmion formation, facilitating identification and design of centrosymmetric skyrmion materials.
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Affiliation(s)
- Joseph A M Paddison
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Binod K Rai
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
- Savannah River National Laboratory, Aiken, South Carolina, 29808, USA
| | - Andrew F May
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Stuart Calder
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Matthew B Stone
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Matthias D Frontzek
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Andrew D Christianson
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
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6
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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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7
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Eto R, Pohle R, Mochizuki M. Low-Energy Excitations of Skyrmion Crystals in a Centrosymmetric Kondo-Lattice Magnet: Decoupled Spin-Charge Excitations and Nonreciprocity. PHYSICAL REVIEW LETTERS 2022; 129:017201. [PMID: 35841562 DOI: 10.1103/physrevlett.129.017201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 04/25/2022] [Accepted: 06/02/2022] [Indexed: 06/15/2023]
Abstract
We theoretically study spin and charge excitations of skyrmion crystals stabilized by conduction-electron-mediated magnetic interactions via spin-charge coupling in a centrosymmetric Kondo-lattice model by large-scale spin-dynamics simulations combined with the kernel polynomial method. We reveal clear segregation of spin and charge excitation channels and nonreciprocal nature of the spin excitations governed by the Fermi-surface geometry, which are unique to the skyrmion crystals in centrosymmetric itinerant hosts and can be a source of novel physical phenomena.
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Affiliation(s)
- Rintaro Eto
- Department of Applied Physics, Waseda University, Okubo, Shinjuku-ku, Tokyo 169-8555, Japan
| | - Rico Pohle
- Department of Applied Physics, Waseda University, Okubo, Shinjuku-ku, Tokyo 169-8555, Japan
- Department of Applied Physics, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Masahito Mochizuki
- Department of Applied Physics, Waseda University, Okubo, Shinjuku-ku, Tokyo 169-8555, Japan
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8
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Bouaziz J, Mendive-Tapia E, Blügel S, Staunton JB. Fermi-Surface Origin of Skyrmion Lattices in Centrosymmetric Rare-Earth Intermetallics. PHYSICAL REVIEW LETTERS 2022; 128:157206. [PMID: 35499873 DOI: 10.1103/physrevlett.128.157206] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 03/11/2022] [Indexed: 06/14/2023]
Abstract
We show from first principles that barrel-shaped structures within the Fermi surface of the centrosymmetric intermetallic compounds GdRu_{2}Si_{2} and Gd_{2}PdSi_{3} give rise to Fermi surface nesting, which determines the strength and sign of quasi-two-dimensional Ruderman-Kittel-Kasuya-Yosida pairwise exchange interactions between the Gd moments. This is the principal mechanism leading to their helical single-q spin-spiral ground states, providing transition temperatures and magnetic periods in good agreement with experiment. Using atomistic spin-dynamic simulations, we draw a direct line between the subtleties of the three-dimensional Fermi surface topology and the stabilization of a square skyrmion lattice in GdRu_{2}Si_{2} at applied magnetic fields as observed in experiment.
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Affiliation(s)
- Juba Bouaziz
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, D-52425 Jülich, Germany
- Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Eduardo Mendive-Tapia
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, D-52425 Jülich, Germany
- Department of Computational Materials Design, Max-Planck-Institut für Eisenforschung, 40237 Düsseldorf, Germany
| | - Stefan Blügel
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, D-52425 Jülich, Germany
| | - Julie B Staunton
- Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
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9
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Khanh ND, Nakajima T, Hayami S, Gao S, Yamasaki Y, Sagayama H, Nakao H, Takagi R, Motome Y, Tokura Y, Arima T, Seki S. Zoology of Multiple-Q Spin Textures in a Centrosymmetric Tetragonal Magnet with Itinerant Electrons. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2105452. [PMID: 35088568 PMCID: PMC8981443 DOI: 10.1002/advs.202105452] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 12/18/2021] [Indexed: 06/14/2023]
Abstract
Magnetic skyrmion is a topologically stable particle-like swirling spin texture potentially suitable for high-density information bit, which was first observed in noncentrosymmetric magnets with Dzyaloshinskii-Moriya interaction. Recently, nanometric skyrmion has also been discovered in centrosymmetric rare-earth compounds, and the identification of their skyrmion formation mechanism and further search of nontrivial spin textures are highly demanded. Here, magnetic structures in a prototypical skyrmion-hosting centrosymmetric tetragonal magnet GdRu2 Si2 is exhaustively studied by performing the resonant X-ray scattering experiments. A rich variety of double-Q magnetic structures, including the antiferroic order of meron(half-skyrmion)/anti-meron-like textures with fractional local topological charges are identified. The observed intricate magnetic phase diagram is successfully reproduced by the theoretical framework considering the four-spin interaction mediated by itinerant electrons and magnetic anisotropy. The present results will contribute to the better understanding of the novel skyrmion formation mechanism in this centrosymmetric rare-earth compound, and suggest that itinerant electrons can ubiquitously host a variety of unique multiple-Q spin orders in a simple crystal lattice system.
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Affiliation(s)
- Nguyen Duy Khanh
- RIKEN Center for Emergent Matter Science (CEMS)WakoJapan
- Institute for Solid State Physics (ISSP)University of TokyoKashiwaJapan
| | - Taro Nakajima
- RIKEN Center for Emergent Matter Science (CEMS)WakoJapan
- Institute for Solid State Physics (ISSP)University of TokyoKashiwaJapan
| | - Satoru Hayami
- Department of Applied PhysicsThe University of TokyoTokyoJapan
- PRESTOJapan Science and Technology Agency (JST)KawaguchiJapan
| | - Shang Gao
- RIKEN Center for Emergent Matter Science (CEMS)WakoJapan
- Materials Science & Technology DivisionNeutron Scattering DivisionOak Ridge National LaboratoryOak RidgeTNUSA
| | - Yuichi Yamasaki
- Research and Services Division of Materials Data and Integrated System (MaDIS)National Institute for Materials Science (NIMS)TsukubaJapan
- PRESTOJapan Science and Technology Agency (JST)KawaguchiJapan
| | - Hajime Sagayama
- Institute of Materials Structure ScienceHigh Energy Accelerator Research OrganizationTsukubaIbarakiJapan
| | - Hironori Nakao
- Institute of Materials Structure ScienceHigh Energy Accelerator Research OrganizationTsukubaIbarakiJapan
| | - Rina Takagi
- Department of Applied PhysicsThe University of TokyoTokyoJapan
- PRESTOJapan Science and Technology Agency (JST)KawaguchiJapan
- Institute of Engineering InnovationThe University of TokyoTokyoJapan
| | | | - Yoshinori Tokura
- RIKEN Center for Emergent Matter Science (CEMS)WakoJapan
- Department of Applied PhysicsThe University of TokyoTokyoJapan
- Tokyo CollegeThe University of TokyoTokyoJapan
| | - Taka‐hisa Arima
- RIKEN Center for Emergent Matter Science (CEMS)WakoJapan
- Department of Advanced Materials ScienceThe University of TokyoKashiwaJapan
| | - Shinichiro Seki
- RIKEN Center for Emergent Matter Science (CEMS)WakoJapan
- Department of Applied PhysicsThe University of TokyoTokyoJapan
- PRESTOJapan Science and Technology Agency (JST)KawaguchiJapan
- Institute of Engineering InnovationThe University of TokyoTokyoJapan
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10
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Takagi R, Matsuyama N, Ukleev V, Yu L, White JS, Francoual S, Mardegan JRL, Hayami S, Saito H, Kaneko K, Ohishi K, Ōnuki Y, Arima TH, Tokura Y, Nakajima T, Seki S. Square and rhombic lattices of magnetic skyrmions in a centrosymmetric binary compound. Nat Commun 2022; 13:1472. [PMID: 35354812 PMCID: PMC8967868 DOI: 10.1038/s41467-022-29131-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 03/01/2022] [Indexed: 11/29/2022] Open
Abstract
Magnetic skyrmions are topologically stable swirling spin textures with particle-like character, and have been intensively studied as a candidate of high-density information bit. While magnetic skyrmions were originally discovered in noncentrosymmetric systems with Dzyaloshinskii-Moriya interaction, recently a nanometric skyrmion lattice has also been reported for centrosymmetric rare-earth compounds, such as Gd2PdSi3 and GdRu2Si2. For the latter systems, a distinct skyrmion formation mechanism mediated by itinerant electrons has been proposed, and the search of a simpler model system allowing for a better understanding of their intricate magnetic phase diagram is highly demanded. Here, we report the discovery of square and rhombic lattices of nanometric skyrmions in a centrosymmetric binary compound EuAl4, by performing small-angle neutron and resonant elastic X-ray scattering experiments. Unlike previously reported centrosymmetric skyrmion-hosting materials, EuAl4 shows multiple-step reorientation of the fundamental magnetic modulation vector as a function of magnetic field, probably reflecting a delicate balance of associated itinerant-electron-mediated interactions. The present results demonstrate that a variety of distinctive skyrmion orders can be derived even in a simple centrosymmetric binary compound, which highlights rare-earth intermetallic systems as a promising platform to realize/control the competition of multiple topological magnetic phases in a single material. Typically, skyrmions appear in magnet systems which are non-centrosymmetric. Here, using neutron and X-ray scattering, Takagi et al show the emergence of a skyrmion phase in the centrosymmetric material EuAl4. This expands the range of materials potential hosting skyrmions.
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Affiliation(s)
- Rina Takagi
- Department of Applied Physics, University of Tokyo, Tokyo, 113-8656, Japan. .,Institute of Engineering Innovation, University of Tokyo, Tokyo, 113-0032, Japan. .,PRESTO, Japan Science and Technology Agency (JST), Kawaguchi, 332-0012, Japan. .,RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan.
| | - Naofumi Matsuyama
- Department of Applied Physics, University of Tokyo, Tokyo, 113-8656, Japan
| | - Victor Ukleev
- Laboratory for Neutron Scattering and Imaging (LNS), Paul Scherrer Institute (PSI), 5232, Villigen, Switzerland
| | - Le Yu
- Laboratory for Neutron Scattering and Imaging (LNS), Paul Scherrer Institute (PSI), 5232, Villigen, Switzerland.,Laboratory for Ultrafast Microscopy and Electron Scattering (LUMES), Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland.,Laboratory of Nanoscale Magnetic Materials and Magnonics (LMGN), Institute of Materials, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Jonathan S White
- Laboratory for Neutron Scattering and Imaging (LNS), Paul Scherrer Institute (PSI), 5232, Villigen, Switzerland
| | - Sonia Francoual
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607, Hamburg, Germany
| | - José R L Mardegan
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607, Hamburg, Germany
| | - Satoru Hayami
- Department of Applied Physics, University of Tokyo, Tokyo, 113-8656, Japan.,PRESTO, Japan Science and Technology Agency (JST), Kawaguchi, 332-0012, Japan
| | - Hiraku Saito
- The Institute for Solid State Physics, University of Tokyo, Kashiwa, 277-8561, Japan
| | - Koji Kaneko
- Materials Sciences Research Center, Japan Atomic Energy Agency, Tokai, 319-1195, Japan.,J-PARC Center, Japan Atomic Energy Agency, Tokai, 319-1195, Japan
| | - Kazuki Ohishi
- Neutron Science and Technology Center, Comprehensive Research Organization for Science and Society (CROSS), Tokai, 319-1106, Japan
| | - Yoshichika Ōnuki
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
| | - Taka-Hisa Arima
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan.,Department of Advanced Materials Science, University of Tokyo, Kashiwa, 277-8561, Japan
| | - Yoshinori Tokura
- 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
| | - Taro Nakajima
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan.,The Institute for Solid State Physics, University of Tokyo, Kashiwa, 277-8561, Japan
| | - Shinichiro Seki
- Department of Applied Physics, University of Tokyo, Tokyo, 113-8656, Japan.,Institute of Engineering Innovation, University of Tokyo, Tokyo, 113-0032, Japan.,PRESTO, Japan Science and Technology Agency (JST), Kawaguchi, 332-0012, Japan.,RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
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11
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Hayami S, Okubo T, Motome Y. Phase shift in skyrmion crystals. Nat Commun 2021; 12:6927. [PMID: 34853320 PMCID: PMC8636495 DOI: 10.1038/s41467-021-27083-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 11/03/2021] [Indexed: 11/28/2022] Open
Abstract
The magnetic skyrmion crystal is a periodic array of a swirling topological spin texture. Since it is regarded as an interference pattern by multiple helical spin density waves, the texture changes with the relative phase shifts among the constituent waves. Although such a phase degree of freedom is relevant to not only magnetism but also transport properties, its effect has not been elucidated thus far. We here theoretically show that a phase shift in the skyrmion crystals leads to a tetra-axial vortex crystal and a meron-antimeron crystal, both of which show a staggered pattern of the scalar spin chirality and give rise to nonreciprocal transport phenomena without the spin-orbit coupling. We demonstrate that such a phase shift can be driven by exchange interactions between the localized spins, thermal fluctuations, and long-range chirality interactions in spin-charge coupled systems. Our results provide a further diversity of topological spin textures and open a new field of emergent electromagnetism by the phase shift engineering. Skyrmions are a type of topological spin texture, which can exist as both an isolated state, and as a skyrmion crystal. Here, Hayami et al present a theoretical study of phase shifts in skyrmion crystals, showing how such phase shifts can lead to other crystalline topological spin textures.
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Affiliation(s)
- Satoru Hayami
- Department of Applied Physics, The University of Tokyo, Tokyo, Japan.
| | - Tsuyoshi Okubo
- Institute for Physics of Intelligence, The University of Tokyo, Tokyo, Japan
| | - Yukitoshi Motome
- Department of Applied Physics, The University of Tokyo, Tokyo, Japan
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12
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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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13
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Nomoto T, Koretsune T, Arita R. Formation Mechanism of the Helical Q Structure in Gd-Based Skyrmion Materials. PHYSICAL REVIEW LETTERS 2020; 125:117204. [PMID: 32975986 DOI: 10.1103/physrevlett.125.117204] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 08/14/2020] [Indexed: 06/11/2023]
Abstract
Using the ab initio local force method, we investigate the formation mechanism of the helical spin structure in GdRu_{2}Si_{2} and Gd_{2}PdSi_{3}. We calculate the paramagnetic spin susceptibility and find that the Fermi surface nesting is not the origin of the incommensurate modulation, in contrast to the naive scenario based on the Ruderman-Kittel-Kasuya-Yosida mechanism. We then decompose the exchange interactions between the Gd spins into each orbital component, and show that spin-density-wave type interaction between the Gd-5d orbitals is ferromagnetic, but the interaction between the Gd-4f orbitals is antiferromagnetic. We conclude that the competition of these two interactions, namely, the interorbital frustration, stabilizes the finite-Q structure.
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Affiliation(s)
- Takuya Nomoto
- Department of Applied Physics, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | | | - Ryotaro Arita
- Department of Applied Physics, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
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14
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Hirschberger M, Spitz L, Nomoto T, Kurumaji T, Gao S, Masell J, Nakajima T, Kikkawa A, Yamasaki Y, Sagayama H, Nakao H, Taguchi Y, Arita R, Arima TH, Tokura Y. Topological Nernst Effect of the Two-Dimensional Skyrmion Lattice. PHYSICAL REVIEW LETTERS 2020; 125:076602. [PMID: 32857583 DOI: 10.1103/physrevlett.125.076602] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 05/16/2020] [Accepted: 07/10/2020] [Indexed: 06/11/2023]
Abstract
The topological Hall effect (THE) and its thermoelectric counterpart, the topological Nernst effect (TNE), are hallmarks of the skyrmion lattice phase (SkL). We observed the giant TNE of the SkL in centrosymmetric Gd_{2}PdSi_{3}, comparable in magnitude to the largest anomalous Nernst signals in ferromagnets. Significant enhancement (suppression) of the THE occurs when doping electrons (holes) to Gd_{2}PdSi_{3}. On the electron-doped side, the topological Hall conductivity approaches the characteristic threshold ∼1000 (Ω cm)^{-1} for the intrinsic regime. We use the filling-controlled samples to confirm Mott's relation between TNE and THE and discuss the importance of Gd-5d orbitals for transport in this compound.
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Affiliation(s)
- Max Hirschberger
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
- Department of Applied Physics and Quantum-Phase Electronics Center, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Leonie Spitz
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
| | - Takuya Nomoto
- Department of Applied Physics and Quantum-Phase Electronics Center, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Takashi Kurumaji
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
| | - Shang Gao
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
| | - Jan Masell
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
| | - Taro Nakajima
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
| | - Akiko Kikkawa
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
| | - Yuichi Yamasaki
- Research and Services Division of Materials Data and Integrated System (MaDIS), National Institute for Materials Science (NIMS), Tsukuba, Ibaraki 305-0047, Japan
- PRESTO, Japan Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012, Japan
| | - Hajime Sagayama
- Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tsukuba, Ibaraki 305-0801, Japan
| | - Hironori Nakao
- Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tsukuba, Ibaraki 305-0801, Japan
| | - Yasujiro Taguchi
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
| | - Ryotaro Arita
- Department of Applied Physics and Quantum-Phase Electronics Center, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Taka-Hisa Arima
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
- Department of Advanced Materials Science, The University of Tokyo, Kashiwa, Chiba 277-8561, Japan
| | - Yoshinori Tokura
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
- Department of Applied Physics and Quantum-Phase Electronics Center, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan
- Tokyo College, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan
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