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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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2
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He B, Jin H, Zheng D, Liu Y, Li J, Hu Y, Wang Y, Zhang J, Peng Y, Wan C, Zhu T, Han X, Zhang S, Yu G. Creation of Room-Temperature Sub-100 nm Antiferromagnetic Skyrmions in an Antiferromagnet IrMn through Interfacial Exchange Coupling. NANO LETTERS 2024; 24:2196-2202. [PMID: 38329428 DOI: 10.1021/acs.nanolett.3c04221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Antiferromagnetic (AFM) skyrmions are magnetic vortices composed of antiparallell-aligned neighboring spins. In stark contrast to conventional skyrmions based on ferromagnetic order, AFM skyrmions have vanished stray fields, higher response frequencies, and rectified translational motion driven by an external force. Therefore, AFM skyrmions promise highly efficient spintronics devices with high bit mobility and density. Nevertheless, the experimental realization of intrinsic AFM skyrmions remains elusive. Here, we show that AFM skyrmions can be nucleated via interfacial exchange coupling at the surface of a room-temperature AFM material, IrMn, exploiting the particular response from uncompensated moments to the thermal annealing and imprinting effects. Further systematic magnetic characterizations validate the existence of such an AFM order at the IrMn/CoFeB interfaces. Such AFM skyrmions have a typical size of 100 nm, which presents pronounced robustness against field and temperature. Our work opens new pathways for magnetic topological devices based on AFM skyrmions.
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Affiliation(s)
- Bin He
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Haonan Jin
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
- ShanghaiTech Laboratory for Topological Physics, ShanghaiTech University, Shanghai 200031, China
| | - Dongfeng Zheng
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Yizhou Liu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jialiang Li
- Spallation Neutron Source Science Center, Dongguan 523803, China
| | - Yue Hu
- Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou University, Lanzhou 730000, China
| | - Yuqiang Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Junwei Zhang
- Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou University, Lanzhou 730000, China
| | - Yong Peng
- Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou University, Lanzhou 730000, China
| | - Caihua Wan
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Tao Zhu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
- Spallation Neutron Source Science Center, Dongguan 523803, China
| | - Xiufeng Han
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Shilei Zhang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
- ShanghaiTech Laboratory for Topological Physics, ShanghaiTech University, Shanghai 200031, China
| | - Guoqiang Yu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
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3
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Ukleev V, Ajejas F, Devishvili A, Vorobiev A, Steinke NJ, Cubitt R, Luo C, Abrudan RM, Radu F, Cros V, Reyren N, White JS. Observation by SANS and PNR of pure Néel-type domain wall profiles and skyrmion suppression below room temperature in magnetic [Pt/CoFeB/Ru] 10 multilayers. SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS 2024; 25:2315015. [PMID: 38455384 PMCID: PMC10919321 DOI: 10.1080/14686996.2024.2315015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 01/29/2024] [Indexed: 03/09/2024]
Abstract
We report investigations of the magnetic textures in periodic multilayers [Pt(1 nm)/(CoFeB(0.8 nm)/Ru(1.4 nm)]10 using polarised neutron reflectometry (PNR) and small-angle neutron scattering (SANS). The multilayers are known to host skyrmions stabilized by Dzyaloshinskii-Moriya interactions induced by broken inversion symmetry and spin-orbit coupling at the asymmetric interfaces. From depth-dependent PNR measurements, we observed well-defined structural features and obtained the layer-resolved magnetization profiles. The in-plane magnetization of the CoFeB layers calculated from fitting of the PNR profiles is found to be in excellent agreement with magnetometry data. Using SANS as a bulk probe of the entire multilayer, we observe long-period magnetic stripe domains and skyrmion ensembles with full orientational disorder at room temperature. No sign of skyrmions is found below 250 K, which we suggest is due to an increase of an effective magnetic anisotropy in the CoFeB layer on cooling that suppresses skyrmion stability. Using polarised SANS at room temperature, we prove the existence of pure Néel-type windings in both stripe domain and skyrmion regimes. No Bloch-type winding admixture, i.e. an indication for hybrid windings, is detected within the measurement sensitivity, in good agreement with expectations according to our micromagnetic modelling of the multilayers. Our findings using neutron techniques provide valuable microscopic insights into the rich magnetic behavior of skyrmion-hosting multilayers, which are essential for the advancement of future skyrmion-based spintronic devices.
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Affiliation(s)
- Victor Ukleev
- Laboratory for Neutron Scattering and Imaging (LNS), Paul Scherrer Institute (PSI), Villigen, Switzerland
- Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany
| | - Fernando Ajejas
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, Palaiseau, France
| | | | - Alexei Vorobiev
- Institut Laue-Langevin, Grenoble, France
- Department of Physics, Uppsala University, Uppsala, Sweden
| | | | | | - Chen Luo
- Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany
| | | | - Florin Radu
- Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany
| | - Vincent Cros
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, Palaiseau, France
| | - Nicolas Reyren
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, Palaiseau, France
| | - Jonathan S. White
- Laboratory for Neutron Scattering and Imaging (LNS), Paul Scherrer Institute (PSI), Villigen, Switzerland
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4
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Darwin E, Tomasello R, Shepley PM, Satchell N, Carpentieri M, Finocchio G, Hickey BJ. Antiferromagnetic interlayer exchange coupled Co 68B 32/Ir/Pt multilayers. Sci Rep 2024; 14:95. [PMID: 38168577 PMCID: PMC10761723 DOI: 10.1038/s41598-023-49976-4] [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: 06/21/2023] [Accepted: 12/14/2023] [Indexed: 01/05/2024] Open
Abstract
Synthetic antiferromagnetic structures can exhibit the advantages of high velocity similarly to antiferromagnets with the additional benefit of being imaged and read-out through techniques applied to ferromagnets. Here, we explore the potential and limits of synthetic antiferromagnets to uncover ways to harness their valuable properties for applications. Two synthetic antiferromagnetic systems have been engineered and systematically investigated to provide an informed basis for creating devices with maximum potential for data storage, logic devices, and skyrmion racetrack memories. The two systems considered are (system 1) CoB/Ir/Pt of N repetitions with Ir inducing the negative coupling between the ferromagnetic layers and (system 2) two ferromagnetically coupled multilayers of CoB/Ir/Pt, coupled together antiferromagnetically with an Ir layer. From the hysteresis, it is found that system 1 shows stable antiferromagnetic interlayer exchange coupling between each magnetic layer up to N = 7. Using Kerr imaging, the two ferromagnetic multilayers in system 2 are shown to undergo separate maze-like switches during hysteresis. Both systems are also studied as a function of temperature and show different behaviors. Micromagnetic simulations predict that in both systems the skyrmion Hall angle is suppressed with the skyrmion velocity five times higher in system 1 than system 2.
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Affiliation(s)
- Emily Darwin
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
- Department of Electrical and Information Engineering, Politecnico Di Bari, Via E. Orabona 4, 70125, Bari, Italy
| | - Riccardo Tomasello
- Department of Electrical and Information Engineering, Politecnico Di Bari, Via E. Orabona 4, 70125, Bari, Italy
| | - Philippa M Shepley
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
| | - Nathan Satchell
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
- Department of Physics, Texas State University, San Marcos, TX, 78666, USA
| | - Mario Carpentieri
- Department of Electrical and Information Engineering, Politecnico Di Bari, Via E. Orabona 4, 70125, Bari, Italy
| | - Giovanni Finocchio
- Department of Mathematical and Computer Sciences, Physical Sciences and Earth Sciences, University of Messina, 98166, Messina, Italy.
| | - B J Hickey
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK.
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5
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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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6
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Burgos-Parra E, Sassi Y, Legrand W, Ajejas F, Léveillé C, Gargiani P, Valvidares M, Reyren N, Cros V, Jaouen N, Flewett S. Probing of three-dimensional spin textures in multilayers by field dependent X-ray resonant magnetic scattering. Sci Rep 2023; 13:11711. [PMID: 37474533 PMCID: PMC10359410 DOI: 10.1038/s41598-023-38029-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 06/30/2023] [Indexed: 07/22/2023] Open
Abstract
In multilayers of magnetic thin films with perpendicular anisotropy, domain walls can take on hybrid configurations in the vertical direction which minimize the domain wall energy, with Néel walls in the top or bottom layers and Bloch walls in some central layers. These types of textures are theoretically predicted, but their observation has remained challenging until recently, with only a few techniques capable of realizing a three dimensional characterization of their magnetization distribution. Here we perform a field dependent X-ray resonant magnetic scattering measurements on magnetic multilayers exploiting circular dichroism contrast to investigate such structures. Using a combination of micromagnetic and X-ray resonant magnetic scattering simulations along with our experimental results, we characterize the three-dimensional magnetic texture of domain walls, notably the thickness resolved characterization of the size and position of the Bloch part in hybrid walls. We also take a step in advancing the resonant scattering methodology by using measurements performed off the multilayer Bragg angle in order to calibrate the effective absorption of the X-rays, and permitting a quantitative evaluation of the out of plane (z) structure of our samples. Beyond hybrid domain walls, this approach can be used to characterize other periodic chiral structures such as skyrmions, antiskyrmions or even magnetic bobbers or hopfions, in both static and dynamic experiments.
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Affiliation(s)
- Erick Burgos-Parra
- Synchrotron SOLEIL, L'Orme des Merisiers, 91192, Gif-sur-Yvette, France.
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France.
- University of Santiago de Chile, Avenida Víctor Jara 3493, Estación Central, Santiago, Chile.
| | - Yanis Sassi
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - William Legrand
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - Fernando Ajejas
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - Cyril Léveillé
- Synchrotron SOLEIL, L'Orme des Merisiers, 91192, Gif-sur-Yvette, France
| | - Pierluigi Gargiani
- ALBA Synchrotron Light Source, Cerdanyola del Vallès, 08290, Barcelona, Spain
| | - Manuel Valvidares
- ALBA Synchrotron Light Source, Cerdanyola del Vallès, 08290, Barcelona, Spain
| | - Nicolas Reyren
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - Vincent Cros
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - Nicolas Jaouen
- Synchrotron SOLEIL, L'Orme des Merisiers, 91192, Gif-sur-Yvette, France
| | - Samuel Flewett
- Pontificia Universidad Católica de Valparaíso, Avenida Universidad 330, Valparaiso, Chile
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7
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Jin H, Tan W, Liu Y, Ran K, Fan R, Shangguan Y, Guang Y, van der Laan G, Hesjedal T, Wen J, Yu G, Zhang S. Evolution of Emergent Monopoles into Magnetic Skyrmion Strings. NANO LETTERS 2023. [PMID: 37263581 DOI: 10.1021/acs.nanolett.3c01117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Topological defects are fundamental concepts in physics, but little is known about the transition between distinct types across different dimensionalities. In topological magnetism, as in field theory, the transition between 1D strings and 0D monopoles is a key process whose observation has remained elusive. Here, we introduce a novel mechanism that allows for the controlled stabilization of emergent monopoles and show that magnetic skyrmion strings can be folded into monopoles. Conversely, they act as seeds out of which the entire string structure can unfold, containing its complete information. In chiral magnets, this process can be observed by resonant elastic X-ray scattering when the objects are in proximity to a polarized ferromagnet, whereby a pure monopole lattice is emerging on the surface. Our experimental proof of the reversible evolution from monopole to string sheds new light on topological defects and establishes the emergent monopole lattice as a new 3D topological phase.
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Affiliation(s)
- Haonan Jin
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 200031, China
- ShanghaiTech Laboratory for Topological Physics, ShanghaiTech University, Shanghai 200031, China
| | - Wancong Tan
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 200031, China
- ShanghaiTech Laboratory for Topological Physics, ShanghaiTech University, Shanghai 200031, China
| | - Yizhou Liu
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
| | - Kejing Ran
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 200031, China
- ShanghaiTech Laboratory for Topological Physics, ShanghaiTech University, Shanghai 200031, China
| | - Raymond Fan
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
| | - Yanyan Shangguan
- National Laboratory of Solid State Microstructures and Department of PhysicsNanjing University, Nanjing, Jiangsu 210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, Jiangsu 210093, China
| | - Yao Guang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Gerrit van der Laan
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
| | - Thorsten Hesjedal
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
- Department of Physics, Clarendon Laboratory, University of Oxford, Oxford OX1 3PU, United Kingdom
| | - Jinsheng Wen
- National Laboratory of Solid State Microstructures and Department of PhysicsNanjing University, Nanjing, Jiangsu 210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, Jiangsu 210093, China
| | - Guoqiang Yu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Shilei Zhang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 200031, China
- ShanghaiTech Laboratory for Topological Physics, ShanghaiTech University, Shanghai 200031, China
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8
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Xu T, Zhang Y, Wang Z, Bai H, Song C, Liu J, Zhou Y, Je SG, N'Diaye AT, Im MY, Yu R, Chen Z, Jiang W. Systematic Control of Ferrimagnetic Skyrmions via Composition Modulation in Pt/Fe 1-xTb x/Ta Multilayers. ACS NANO 2023; 17:7920-7928. [PMID: 37010987 DOI: 10.1021/acsnano.3c02006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Magnetic skyrmions are topological spin textures that can be used as memory and logic components for advancing the next generation spintronics. In this regard, control of nanoscale skyrmions, including their sizes and densities, is of particular importance for enhancing the storage capacity of skyrmionic devices. Here, we propose a viable route for engineering ferrimagnetic skyrmions via tuning the magnetic properties of the involved ferrimagnets Fe1-xTbx. Via tuning the composition of Fe1-xTbx that alters the magnetic anisotropy and the saturation magnetization, the size of the ferrimagnetic skyrmion (ds) and the average density (ηs) can be effectively tailored in [Pt/Fe1-xTbx/Ta]10 multilayers. In particular, a stabilization of sub-50 nm skyrmions with a high density is demonstrated at room temperature. Our work provides an effective approach for designing ferrimagnetic skyrmions with the desired size and density, which could be useful for enabling high-density ferrimagnetic skyrmionics.
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Affiliation(s)
- Teng Xu
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
| | - Yuxuan Zhang
- School of Materials Science and Engineering, The State Key Laboratory of New Ceramics and Fine Processing, MOE Key Laboratory of Advanced Materials, Tsinghua University, Beijing 100084, China
| | - Zidong Wang
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, Guangdong 518172, China
| | - Hao Bai
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
| | - Chengkun Song
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
| | - Jiahao Liu
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
| | - Yan Zhou
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, Guangdong 518172, China
| | - Soong-Geun Je
- Lawrence Berkeley National Laboratory, Cyclotron Road, Berkeley, California 94720, United States
| | - Alpha T N'Diaye
- Lawrence Berkeley National Laboratory, Cyclotron Road, Berkeley, California 94720, United States
| | - Mi-Young Im
- Lawrence Berkeley National Laboratory, Cyclotron Road, Berkeley, California 94720, United States
| | - Rong Yu
- School of Materials Science and Engineering, The State Key Laboratory of New Ceramics and Fine Processing, MOE Key Laboratory of Advanced Materials, Tsinghua University, Beijing 100084, China
| | - Zhen Chen
- School of Materials Science and Engineering, The State Key Laboratory of New Ceramics and Fine Processing, MOE Key Laboratory of Advanced Materials, Tsinghua University, Beijing 100084, China
| | - Wanjun Jiang
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
- Collaborative Innovation Center of Quantum Matter, Beijing 100084, China
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9
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McCarter MR, Kim KT, Stoica VA, Das S, Klewe C, Donoway EP, Burn DM, Shafer P, Rodolakis F, Gonçalves MAP, Gómez-Ortiz F, Íñiguez J, García-Fernández P, Junquera J, Lovesey SW, van der Laan G, Park SY, Freeland JW, Martin LW, Lee DR, Ramesh R. Structural Chirality of Polar Skyrmions Probed by Resonant Elastic X-Ray Scattering. PHYSICAL REVIEW LETTERS 2022; 129:247601. [PMID: 36563236 DOI: 10.1103/physrevlett.129.247601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 03/08/2022] [Accepted: 10/23/2022] [Indexed: 06/17/2023]
Abstract
An escalating challenge in condensed-matter research is the characterization of emergent order-parameter nanostructures such as ferroelectric and ferromagnetic skyrmions. Their small length scales coupled with complex, three-dimensional polarization or spin structures makes them demanding to trace out fully. Resonant elastic x-ray scattering (REXS) has emerged as a technique to study chirality in spin textures such as skyrmions and domain walls. It has, however, been used to a considerably lesser extent to study analogous features in ferroelectrics. Here, we present a framework for modeling REXS from an arbitrary arrangement of charge quadrupole moments, which can be applied to nanostructures in materials such as ferroelectrics. With this, we demonstrate how extended reciprocal space scans using REXS with circularly polarized x rays can probe the three-dimensional structure and chirality of polar skyrmions. Measurements, bolstered by quantitative scattering calculations, show that polar skyrmions of mixed chirality coexist, and that REXS allows valuation of relative fractions of right- and left-handed skyrmions. Our quantitative analysis of the structure and chirality of polar skyrmions highlights the capability of REXS for establishing complex topological structures toward future application exploits.
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Affiliation(s)
- Margaret R McCarter
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - Kook Tae Kim
- Department of Physics, Soongsil University, Seoul 06978, Korea
| | - Vladimir A Stoica
- Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, USA
- Department of Materials Science and Engineering, Pennsylvania State University, Pennsylvania 16802, USA
| | - Sujit Das
- Materials Research Centre, Indian Institute of Science, Bangalore 560012, India
| | - Christoph Klewe
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Elizabeth P Donoway
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - David M Burn
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Padraic Shafer
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Fanny Rodolakis
- Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - Mauro A P Gonçalves
- Institute of Physics of the Czech Academy of Sciences, 18221 Prague 8, Czech Republic
| | - Fernando Gómez-Ortiz
- Departmento de Ciencias de la Tierra y Física de la Materia Condensada, Universidad de Cantabria, 39005 Santander, Spain
| | - Jorge Íñiguez
- Materials Research and Technology Department, Luxembourg Institute of Science and Technology (LIST), 5 avenue des Hauts-Fourneaux, L-4362 Esch/Alzette, Luxemburg
- Department of Physics and Materials Science, University of Luxembourg, Rue du Brill 41, L-4422 Belvaux, Luxembourg
| | - Pablo García-Fernández
- Departmento de Ciencias de la Tierra y Física de la Materia Condensada, Universidad de Cantabria, 39005 Santander, Spain
| | - Javier Junquera
- Departmento de Ciencias de la Tierra y Física de la Materia Condensada, Universidad de Cantabria, 39005 Santander, Spain
| | - Stephen W Lovesey
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
- Department of Physics, Oxford University, Oxford OX1 3PU, United Kingdom
| | - Gerrit van der Laan
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Se Young Park
- Department of Physics, Soongsil University, Seoul 06978, Korea
| | - John W Freeland
- Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - Lane W Martin
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Dong Ryeol Lee
- Department of Physics, Soongsil University, Seoul 06978, Korea
| | - Ramamoorthy Ramesh
- Department of Physics, University of California, Berkeley, California 94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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10
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He M, Xu T, Gao Y, Hu C, Cai J, Zhang Y. Mixed-Type Skyrmions in Symmetric Pt/Co/Pt Multilayers at Room Temperature. MATERIALS (BASEL, SWITZERLAND) 2022; 15:8272. [PMID: 36431758 PMCID: PMC9698406 DOI: 10.3390/ma15228272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 11/14/2022] [Accepted: 11/18/2022] [Indexed: 06/16/2023]
Abstract
We demonstrate the generation of mixed-type skyrmions (all are about 200 nm) that are primarily Bloch-type, hybrid-type, and a negligible amount of Néel-type in symmetric Pt/Co(1.55)/Pt multilayers at room temperature. The magnetic field dependence of skyrmion evolution is reversible. Brillouin light-scattering is used to quantitatively quantify the Dzyaloshinskii-Moriya interaction constant D in order to comprehend the mechanism. Interestingly, the D value is high enough to generate skyrmions in a symmetric sandwich structure. Micromagnetic simulations show that Néel-type skyrmions transform into Bloch-type skyrmions as the D value decreases. The interface-induced non-uniform D may be the cause to generate mixed-type skyrmions. This work broadens the flexibility to generate skyrmions by engineering skyrmion-based devices with nominally symmetric multilayers without the requirement of very large DMI.
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Affiliation(s)
- Min He
- School of Physics and Electronic Information, Yantai University, Yantai 264005, China
| | - Tiankuo Xu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yang Gao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Chaoqun Hu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, 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 100049, China
| | - 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 100049, China
- Songshan Lake Materials Laboratory, Dongguan 523808, China
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11
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Ukleev V, Luo C, Abrudan R, Aqeel A, Back CH, Radu F. Chiral surface spin textures in Cu 2OSeO 3 unveiled by soft X-ray scattering in specular reflection geometry. SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS 2022; 23:682-690. [PMID: 36277505 PMCID: PMC9586675 DOI: 10.1080/14686996.2022.2131466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 09/23/2022] [Accepted: 09/23/2022] [Indexed: 06/16/2023]
Abstract
Resonant elastic soft X-ray magnetic scattering (XRMS) is a powerful tool to explore long-periodic spin textures in single crystals. However, due to the limited momentum transfer range imposed by long wavelengths of photons in the soft x-ray region, Bragg diffraction is restricted to crystals with the large lattice parameters. Alternatively, small-angle X-ray scattering has been involved in the soft energy X-ray range which, however, brings in difficulties with the sample preparation that involves focused ion beam milling to thin down the crystal to below a few hundred nm thickness. We show how to circumvent these restrictions using XRMS in specular reflection from a sub-nanometer smooth crystal surface. The method allows observing diffraction peaks from the helical and conical spin modulations at the surface of a Cu 2 OSeO 3 single crystal and probing their corresponding chirality as contributions to the dichroic scattered intensity. The results suggest a promising way to carry out XRMS studies on a plethora of noncentrosymmetric systems hitherto unexplored with soft X-rays due to the absence of the commensurate Bragg peaks in the available momentum transfer range.
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Affiliation(s)
- V. Ukleev
- Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany
| | - C. Luo
- Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany
- Physik-Department, Technische Universität München, Garching, Germany
| | - R. Abrudan
- Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany
| | - A. Aqeel
- Physik-Department, Technische Universität München, Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), München, Germany
| | - C. H. Back
- Physik-Department, Technische Universität München, Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), München, Germany
| | - F. Radu
- Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany
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12
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Juge R, Sisodia N, Larrañaga JU, Zhang Q, Pham VT, Rana KG, Sarpi B, Mille N, Stanescu S, Belkhou R, Mawass MA, Novakovic-Marinkovic N, Kronast F, Weigand M, Gräfe J, Wintz S, Finizio S, Raabe J, Aballe L, Foerster M, Belmeguenai M, Buda-Prejbeanu LD, Pelloux-Prayer J, Shaw JM, Nembach HT, Ranno L, Gaudin G, Boulle O. Skyrmions in synthetic antiferromagnets and their nucleation via electrical current and ultra-fast laser illumination. Nat Commun 2022; 13:4807. [PMID: 35974009 PMCID: PMC9381802 DOI: 10.1038/s41467-022-32525-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 08/03/2022] [Indexed: 11/09/2022] Open
Abstract
Magnetic skyrmions are topological spin textures that hold great promise as nanoscale information carriers in non-volatile memory and logic devices. While room-temperature magnetic skyrmions and their current-induced motion were recently demonstrated, the stray field resulting from their finite magnetisation and their topological charge limit their minimum size and reliable motion. Antiferromagnetic skyrmions allow to lift these limitations owing to their vanishing magnetisation and net zero topological charge, promising ultra-small and ultra-fast skyrmions. Here, we report on the observation of isolated skyrmions in compensated synthetic antiferromagnets at zero field and room temperature using X-ray magnetic microscopy. Micromagnetic simulations and an analytical model confirm the chiral antiferromagnetic nature of these skyrmions and allow the identification of the physical mechanisms controlling their size and stability. Finally, we demonstrate the nucleation of synthetic antiferromagnetic skyrmions via local current injection and ultra-fast laser excitation.
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Affiliation(s)
- Roméo Juge
- Univ. Grenoble Alpes, CNRS, CEA, SPINTEC, 38000, Grenoble, France
| | - Naveen Sisodia
- Univ. Grenoble Alpes, CNRS, CEA, SPINTEC, 38000, Grenoble, France
| | | | - Qiang Zhang
- Univ. Grenoble Alpes, CNRS, CEA, SPINTEC, 38000, Grenoble, France
| | - Van Tuong Pham
- Univ. Grenoble Alpes, CNRS, CEA, SPINTEC, 38000, Grenoble, France
| | | | - Brice Sarpi
- Synchrotron SOLEIL, L'Orme des Merisiers, 91190, Saint-Aubin, France
| | - Nicolas Mille
- Synchrotron SOLEIL, L'Orme des Merisiers, 91190, Saint-Aubin, France
| | - Stefan Stanescu
- Synchrotron SOLEIL, L'Orme des Merisiers, 91190, Saint-Aubin, France
| | - Rachid Belkhou
- Synchrotron SOLEIL, L'Orme des Merisiers, 91190, Saint-Aubin, France
| | - Mohamad-Assaad Mawass
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, 12489, Berlin, Germany
| | - Nina Novakovic-Marinkovic
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, 12489, Berlin, Germany
| | - Florian Kronast
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, 12489, Berlin, Germany
| | - Markus Weigand
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109, Berlin, Germany
| | - Joachim Gräfe
- Max Planck Institute for Intelligent Systems, Heisenbergstraße 3, 70569, Stuttgart, Germany
| | - Sebastian Wintz
- Max Planck Institute for Intelligent Systems, Heisenbergstraße 3, 70569, Stuttgart, Germany
| | - Simone Finizio
- Swiss Light Source, Paul Scherrer Institut, 5232, Villigen, Switzerland
| | - Jörg Raabe
- Swiss Light Source, Paul Scherrer Institut, 5232, Villigen, Switzerland
| | - Lucia Aballe
- ALBA Synchrotron Light Facility, 08290, Cerdanyola del Vallès, Barcelona, Spain
| | - Michael Foerster
- ALBA Synchrotron Light Facility, 08290, Cerdanyola del Vallès, Barcelona, Spain
| | - Mohamed Belmeguenai
- Laboratoire des Sciences des Procedés et des Matériaux, CNRS, Univ. Paris 13, 93430, Villetaneuse, France
| | | | | | - Justin M Shaw
- Quantum Electromagnetics Division, National Institute of Standards and Technology, Boulder, CO, 80309, USA
| | - Hans T Nembach
- Quantum Electromagnetics Division, National Institute of Standards and Technology, Boulder, CO, 80309, USA.,Department of Physics, University of Colorado, Boulder, CO, 80309, USA
| | - Laurent Ranno
- Univ. Grenoble Alpes, CNRS, Institut Néel, 38042, Grenoble, France
| | - Gilles Gaudin
- Univ. Grenoble Alpes, CNRS, CEA, SPINTEC, 38000, Grenoble, France
| | - Olivier Boulle
- Univ. Grenoble Alpes, CNRS, CEA, SPINTEC, 38000, Grenoble, France.
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13
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Fujita R, Bassirian P, Li Z, Guo Y, Mawass MA, Kronast F, van der Laan G, Hesjedal T. Layer-Dependent Magnetic Domains in Atomically Thin Fe 5GeTe 2. ACS NANO 2022; 16:10545-10553. [PMID: 35802911 PMCID: PMC9331157 DOI: 10.1021/acsnano.2c01948] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Magnetic domain formation in two-dimensional (2D) materials gives perspectives into the fundamental origins of 2D magnetism and also motivates the development of advanced spintronics devices. However, the characterization of magnetic domains in atomically thin van der Waals (vdW) flakes remains challenging. Here, we employ X-ray photoemission electron microscopy (XPEEM) to perform layer-resolved imaging of the domain structures in the itinerant vdW ferromagnet Fe5GeTe2 which shows near room temperature bulk ferromagnetism and a weak perpendicular magnetic anisotropy (PMA). In the bulk limit, we observe the well-known labyrinth-type domains. Thinner flakes, on the other hand, are characterized by increasingly fragmented domains. While PMA is a characteristic property of Fe5GeTe2, we observe a spin-reorientation transition with the spins canting in-plane for flakes thinner than six layers. Notably, a bubble phase emerges in four-layer flakes. This thickness dependence, which clearly deviates from the single-domain behavior observed in other 2D magnetic materials, demonstrates the exciting prospect of stabilizing complex spin textures in 2D vdW magnets at relatively high temperatures.
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Affiliation(s)
- Ryuji Fujita
- Clarendon
Laboratory, Department of Physics, University
of Oxford, Parks Road, Oxford, OX1
3PU, United Kingdom
| | - Pedram Bassirian
- Clarendon
Laboratory, Department of Physics, University
of Oxford, Parks Road, Oxford, OX1
3PU, United Kingdom
- Max
Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle, Germany
| | - Zhengxian Li
- School
of Physical Science and Technology, ShanghaiTech
University, Shanghai 201210, China
| | - Yanfeng Guo
- School
of Physical Science and Technology, ShanghaiTech
University, Shanghai 201210, China
| | - Mohamad A. Mawass
- Helmholtz-Zentrum
Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
| | - Florian Kronast
- Helmholtz-Zentrum
Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
| | - Gerrit van der Laan
- Diamond
Light Source, Harwell Science and Innovation
Campus, Didcot, OX11 0DE, United Kingdom
| | - Thorsten Hesjedal
- Clarendon
Laboratory, Department of Physics, University
of Oxford, Parks Road, Oxford, OX1
3PU, United Kingdom
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14
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Yıldırım O, Tomasello R, Feng Y, Carlotti G, Tacchi S, Vaghefi PM, Giordano A, Dutta T, Finocchio G, Hug HJ, Mandru AO. Tuning the Coexistence Regime of Incomplete and Tubular Skyrmions in Ferromagnetic/Ferrimagnetic/Ferromagnetic Trilayers. ACS APPLIED MATERIALS & INTERFACES 2022; 14:34002-34010. [PMID: 35830277 DOI: 10.1021/acsami.2c06608] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The development of skyrmionic devices requires a suitable tuning of material parameters to stabilize skyrmions and control their density. It has been demonstrated recently that different skyrmion types can be simultaneously stabilized at room temperature in heterostructures involving ferromagnets, ferrimagnets, and heavy metals, offering a new platform of coding binary information in the type of skyrmion instead of the presence/absence of skyrmions. Here, we tune the energy landscape of the two skyrmion types in such heterostructures by engineering the geometrical and material parameters of the individual layers. We find that a fine adjustment of the ferromagnetic layer thickness, and thus its magnetic anisotropy, allows the trilayer system to support either one of the skyrmion types or the coexistence of both and with varying densities.
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Affiliation(s)
- Oğuz Yıldırım
- Empa, Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Dübendorf, Switzerland
| | - Riccardo Tomasello
- Department of Electrical and Information Engineering, Politecnico di Bari, 70125 Bari, Italy
| | - Yaoxuan Feng
- Empa, Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Dübendorf, Switzerland
| | - Giovanni Carlotti
- Dipartimento di Fisica e Geologia, Università di Perugia, 06123 Perugia, Italy
| | - Silvia Tacchi
- Istituto Officina dei Materiali del CNR (CNR-IOM), Sede Secondaria di Perugia, c/o Dipartimento di Fisica e Geologia, Università di Perugia, 06123 Perugia, Italy
| | - Pegah Mirzadeh Vaghefi
- Empa, Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Dübendorf, Switzerland
| | - Anna Giordano
- Department of Mathematical and Computer Sciences, Physical Sciences and Earth Sciences, University of Messina, I-98166 Messina, Italy
| | - Tanmay Dutta
- Empa, Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Dübendorf, Switzerland
| | - Giovanni Finocchio
- Department of Mathematical and Computer Sciences, Physical Sciences and Earth Sciences, University of Messina, I-98166 Messina, Italy
| | - Hans J Hug
- Empa, Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Dübendorf, Switzerland
- Department of Physics, University of Basel, CH-4056 Basel, Switzerland
| | - Andrada-Oana Mandru
- Empa, Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Dübendorf, Switzerland
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15
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Ran K, Liu Y, Jin H, Shangguan Y, Guang Y, Wen J, Yu G, van der Laan G, Hesjedal T, Zhang S. Axially Bound Magnetic Skyrmions: Glueing Topological Strings Across an Interface. NANO LETTERS 2022; 22:3737-3743. [PMID: 35451843 PMCID: PMC9101076 DOI: 10.1021/acs.nanolett.2c00689] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 04/04/2022] [Indexed: 06/03/2023]
Abstract
A major challenge in topological magnetism lies in the three-dimensional (3D) exploration of their magnetic textures. A recent focus has been the question of how 2D skyrmion sheets vertically stack to form distinct types of 3D topological strings. Being able to manipulate the vertical coupling should therefore provide a route to the engineering of topological states. Here, we present a new type of axially bound magnetic skyrmion string state in which the strings in two distinct materials are glued together across their interface. With quasi-tomographic resonant elastic X-ray scattering, the 3D skyrmion profiles before and after their binding across the interface were unambiguously determined and compared. Their attractive binding is accompanied by repulsive twisting; i.e., the coupled skyrmions mutually affect each other via a compensating twisting. This state exists in chiral magnet-magnetic thin film heterostructures, providing a new arena for the engineering of 3D topological phases.
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Affiliation(s)
- Kejing Ran
- School
of Physical Science and Technology, ShanghaiTech
University, Shanghai 200031, China
- ShanghaiTech
Laboratory for Topological Physics, ShanghaiTech
University, Shanghai 200031, China
| | - Yizhou Liu
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - Haonan Jin
- School
of Physical Science and Technology, ShanghaiTech
University, Shanghai 200031, China
- ShanghaiTech
Laboratory for Topological Physics, ShanghaiTech
University, Shanghai 200031, China
| | - Yanyan Shangguan
- National
Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, China and Collaborative Innovation Center of Advanced
Microstructures, Nanjing 210093, China
| | - Yao Guang
- Beijing
National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jinsheng Wen
- National
Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, China and Collaborative Innovation Center of Advanced
Microstructures, Nanjing 210093, China
| | - Guoqiang Yu
- Beijing
National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Gerrit van der Laan
- Diamond
Light Source, Harwell Science and Innovation
Campus, Didcot OX11 0DE, United Kingdom
| | - Thorsten Hesjedal
- Clarendon
Laboratory, Department of Physics, University
of Oxford, Parks Road, Oxford OX1
3PU, United Kingdom
| | - Shilei Zhang
- School
of Physical Science and Technology, ShanghaiTech
University, Shanghai 200031, China
- ShanghaiTech
Laboratory for Topological Physics, ShanghaiTech
University, Shanghai 200031, China
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16
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Chiral structures of electric polarization vectors quantified by X-ray resonant scattering. Nat Commun 2022; 13:1769. [PMID: 35383159 PMCID: PMC8983710 DOI: 10.1038/s41467-022-29359-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Accepted: 03/07/2022] [Indexed: 11/08/2022] Open
Abstract
Resonant elastic X-ray scattering (REXS) offers a unique tool to investigate solid-state systems providing spatial knowledge from diffraction combined with electronic information through the enhanced absorption process, allowing the probing of magnetic, charge, spin, and orbital degrees of spatial order together with electronic structure. A new promising application of REXS is to elucidate the chiral structure of electrical polarization emergent in a ferroelectric oxide superlattice in which the polarization vectors in the REXS amplitude are implicitly described through an anisotropic tensor corresponding to the quadrupole moment. Here, we present a detailed theoretical framework and analysis to quantitatively analyze the experimental results of Ti L-edge REXS of a polar vortex array formed in a PbTiO3/SrTiO3 superlattice. Based on this theoretical framework, REXS for polar chiral structures can become a useful tool similar to x-ray resonant magnetic scattering (XRMS), enabling a comprehensive study of both electric and magnetic REXS on the chiral structures. The polar chiral texture of the vortex or skyrmion structure in ferroelectric oxide PbTiO3/SrTiO3 superlattice attracts attention. Here, the authors report a theoretical framework to probe emergent chirality of electrical polarization textures.
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17
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Wu Y, Francisco B, Chen Z, Wang W, Zhang Y, Wan C, Han X, Chi H, Hou Y, Lodesani A, Yin G, Liu K, Cui YT, Wang KL, Moodera JS. A Van der Waals Interface Hosting Two Groups of Magnetic Skyrmions. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2110583. [PMID: 35218078 DOI: 10.1002/adma.202110583] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 01/26/2022] [Indexed: 06/14/2023]
Abstract
Multiple magnetic skyrmion phases add an additional degree of freedom for skyrmion-based ultrahigh-density spin memory devices. Extending the field to 2D van der Waals magnets is a rewarding challenge, where the realizable degree of freedoms (e.g., thickness, twist angle, and electrical gating) and high skyrmion density result in intriguing new properties and enhanced functionality. In this work, a van der Waals interface, formed by two 2D ferromagnets Cr2 Ge2 Te6 and Fe3 GeTe2 with a Curie temperature of ≈65 and ≈205 K, respectively, hosting two groups of magnetic skyrmions, is reported. Two sets of topological Hall effect signals are observed below 6s0 K when Cr2 Ge2 Te6 is magnetically ordered. These two groups of skyrmions are directly imaged using magnetic force microscopy, and supported by micromagnetic simulations. Interestingly, the magnetic skyrmions persist in the heterostructure with zero applied magnetic field. The results are promising for the realization of skyrmionic devices based on van der Waals heterostructures hosting multiple skyrmion phases.
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Affiliation(s)
- Yingying Wu
- Francis Bitter Magnet Laboratory and Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Brian Francisco
- Department of Physics and Astronomy, University of California, Riverside, CA, 92521, USA
| | - Zhijie Chen
- Department of Physics, Georgetown University, Washington, D.C., 20057, USA
| | - Wei Wang
- Key Laboratory of Flexible Electronics & Institute of Advanced Materials, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, Nanjing, 211816, China
| | - Yu Zhang
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Caihua Wan
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Xiufeng Han
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Hang Chi
- Francis Bitter Magnet Laboratory and Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- U.S. Army CCDC Army Research Laboratory, Adelphi, MD, 20783, USA
| | - Yasen Hou
- Francis Bitter Magnet Laboratory and Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Alessandro Lodesani
- Francis Bitter Magnet Laboratory and Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Gen Yin
- Department of Physics, Georgetown University, Washington, D.C., 20057, USA
| | - Kai Liu
- Department of Physics, Georgetown University, Washington, D.C., 20057, USA
| | - Yong-Tao Cui
- Department of Physics and Astronomy, University of California, Riverside, CA, 92521, USA
| | - Kang L Wang
- Department of Electrical and Computer Engineering, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Jagadeesh S Moodera
- Francis Bitter Magnet Laboratory and Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Physics Department, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
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18
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Jiang L, Huang C, Zhu Y, Pan Y, Fan J, Zhang K, Ma C, Shi D, Zhang H. Tuning the size of skyrmion by strain at the Co/Pt3 Interfaces. iScience 2022; 25:104039. [PMID: 35330683 PMCID: PMC8938285 DOI: 10.1016/j.isci.2022.104039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 02/09/2022] [Accepted: 03/03/2022] [Indexed: 11/25/2022] Open
Abstract
Based on density functional theory calculations, we elucidated the tunability of the atomic structures and magnetic interactions of Co/Pt3 interface (one layer of hcp(0001) Co and three layers of fcc(111) Pt) and thus the skyrmion sizes using strain. The dispersion relations of the spin spiral in the opposite directions, E(q) and E(-q), were evaluated based on generalized Bloch equations. Effective exchange coupling (EC) and Dzyaloshinsky-Moriya interaction (DMI) parameters between different neighbors Ji and di at different lattice constants were derived by fitting the resulting spin spiral dispersion E(q) to EC model with DMI and E(q)-E(-q) formula, respectively. We observed an increase in DMI and a significant decrease in EC with an increase in strain. Hence, the size of Néel-type skyrmions determined by the ratio of EC/DMI can be controlled by applying strain, leading to an effective approach to tailor the formation of skyrmion lattices by inducing slight structural modifications on the magnetic thin films. Calculate the EC and DMI of multi-nearest neighbors in the VASP program Show detailed changes of multi-nearest neighboring EC and DMI with deformation The size of skyrmion does decrease as the lattice constant increases Distance between Co and Pt layer determines the size of DMI
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19
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Guang Y, Ran K, Zhang J, Liu Y, Zhang S, Qiu X, Peng Y, Zhang X, Weigand M, Gräfe J, Schütz G, van der Laan G, Hesjedal T, Zhang S, Yu G, Han X. Superposition of Emergent Monopole and Antimonopole in CoTb Thin Films. PHYSICAL REVIEW LETTERS 2021; 127:217201. [PMID: 34860082 DOI: 10.1103/physrevlett.127.217201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Accepted: 10/19/2021] [Indexed: 06/13/2023]
Abstract
A three-dimensional singular point that consists of two oppositely aligned emergent monopoles is identified in continuous CoTb thin films, as confirmed by complementary techniques of resonant elastic x-ray scattering, Lorentz transmission electron microscopy, and scanning transmission x-ray microscopy. This new type of topological defect can be regarded as a superposition of an emergent magnetic monopole and an antimonopole, around which the source and drain of the magnetic flux overlap in space. We experimentally prove that the observed spin twist seen in Lorentz transmission electron microscopy reveals the cross section of the superimposed three-dimensional structure, providing a straightforward strategy for the observation of magnetic singularities. Such a quasiparticle provides an excellent platform for studying the rich physics of emergent electromagnetism.
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Affiliation(s)
- Yao Guang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Kejing Ran
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
- ShanghaiTech Laboratory for Topological Physics, ShanghaiTech University, Shanghai 201210, China
| | - Junwei Zhang
- School of Materials and Energy, Electron Microscopy Centre of Lanzhou University and Key Laboratory of Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou 730000, People's Republic of China
| | - Yizhou Liu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Senfu Zhang
- Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou University, Lanzhou 730000, China
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Xuepeng Qiu
- Shanghai Key Laboratory of Special Artificial Microstructure Materials & School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
| | - Yong Peng
- School of Materials and Energy, Electron Microscopy Centre of Lanzhou University and Key Laboratory of Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou 730000, People's Republic of China
| | - Xixiang Zhang
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Markus Weigand
- Max-Planck-Institut für Intelligente Systeme, Stuttgart 70569, Germany
| | - Joachim Gräfe
- Max-Planck-Institut für Intelligente Systeme, Stuttgart 70569, Germany
| | - Gisela Schütz
- Max-Planck-Institut für Intelligente Systeme, Stuttgart 70569, Germany
| | - Gerrit van der Laan
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
| | - Thorsten Hesjedal
- Department of Physics, Clarendon Laboratory, University of Oxford, Oxford OX1 3PU, United Kingdom
| | - Shilei Zhang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
- ShanghaiTech Laboratory for Topological Physics, ShanghaiTech University, Shanghai 201210, China
| | - Guoqiang Yu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Xiufeng Han
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
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20
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Zayko S, Kfir O, Heigl M, Lohmann M, Sivis M, Albrecht M, Ropers C. Ultrafast high-harmonic nanoscopy of magnetization dynamics. Nat Commun 2021; 12:6337. [PMID: 34732725 PMCID: PMC8566501 DOI: 10.1038/s41467-021-26594-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Accepted: 08/10/2021] [Indexed: 11/25/2022] Open
Abstract
Light-induced magnetization changes, such as all-optical switching, skyrmion nucleation, and intersite spin transfer, unfold on temporal and spatial scales down to femtoseconds and nanometers, respectively. Pump-probe spectroscopy and diffraction studies indicate that spatio-temporal dynamics may drastically affect the non-equilibrium magnetic evolution. Yet, direct real-space magnetic imaging on the relevant timescales has remained challenging. Here, we demonstrate ultrafast high-harmonic nanoscopy employing circularly polarized high-harmonic radiation for real-space imaging of femtosecond magnetization dynamics. We map quenched magnetic domains and localized spin structures in Co/Pd multilayers with a sub-wavelength spatial resolution down to 16 nm, and strobosocopically trace the local magnetization dynamics with 40 fs temporal resolution. Our compact experimental setup demonstrates the highest spatio-temporal resolution of magneto-optical imaging to date. Facilitating ultrafast imaging with high sensitivity to chiral and linear dichroism, we envisage a wide range of applications spanning magnetism, phase transitions, and carrier dynamics.
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Affiliation(s)
- Sergey Zayko
- 4th Physical Institute-Solids and Nanostructures, University of Göttingen, 37077, Göttingen, Germany.
- Max Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany.
| | - Ofer Kfir
- 4th Physical Institute-Solids and Nanostructures, University of Göttingen, 37077, Göttingen, Germany
- Max Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany
- School of Electrical Engineering, Tel Aviv University, 69978, Tel Aviv, Israel
| | - Michael Heigl
- Institute of Physics, University of Augsburg, 86159, Augsburg, Germany
| | - Michael Lohmann
- 4th Physical Institute-Solids and Nanostructures, University of Göttingen, 37077, Göttingen, Germany
| | - Murat Sivis
- 4th Physical Institute-Solids and Nanostructures, University of Göttingen, 37077, Göttingen, Germany
- Max Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany
| | - Manfred Albrecht
- Institute of Physics, University of Augsburg, 86159, Augsburg, Germany
| | - Claus Ropers
- 4th Physical Institute-Solids and Nanostructures, University of Göttingen, 37077, Göttingen, Germany
- Max Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany
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21
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Tang J, Wu Y, Kong L, Wang W, Chen Y, Wang Y, Soh Y, Xiong Y, Tian M, Du H. Two-dimensional characterization of three-dimensional magnetic bubbles in Fe 3Sn 2 nanostructures. Natl Sci Rev 2021; 8:nwaa200. [PMID: 34691660 PMCID: PMC8288175 DOI: 10.1093/nsr/nwaa200] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 06/04/2020] [Accepted: 08/04/2020] [Indexed: 11/13/2022] Open
Abstract
We report differential phase contrast scanning transmission electron microscopy (TEM) of nanoscale magnetic objects in Kagome ferromagnet Fe3Sn2 nanostructures. This technique can directly detect the deflection angle of a focused electron beam, thus allowing clear identification of the real magnetic structures of two magnetic objects including three-ring and complex arch-shaped vortices in Fe3Sn2 by Lorentz-TEM imaging. Numerical calculations based on real material-specific parameters well reproduced the experimental results, showing that the magnetic objects can be attributed to integral magnetizations of two types of complex three-dimensional (3D) magnetic bubbles with depth-modulated spin twisting. Magnetic configurations obtained using the high-resolution TEM are generally considered as two-dimensional (2D) magnetic objects previously. Our results imply the importance of the integral magnetizations of underestimated 3D magnetic structures in 2D TEM magnetic characterizations.
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Affiliation(s)
- Jin Tang
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory of the Chinese Academy of Sciences, and University of Science and Technology of China, Hefei 230031, China
| | - Yaodong Wu
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory of the Chinese Academy of Sciences, and University of Science and Technology of China, Hefei 230031, China
- Universities Joint Key Laboratory of Photoelectric Detection Science and Technology in Anhui Province, Hefei Normal University, Hefei 230601, China
| | - Lingyao Kong
- School of Physics and Materials Science, Anhui University, Hefei 230601, China
| | - Weiwei Wang
- Institute of Physical Science and Information Technology, Anhui University, Hefei 230601, China
| | - Yutao Chen
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory of the Chinese Academy of Sciences, and University of Science and Technology of China, Hefei 230031, China
| | - Yihao Wang
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory of the Chinese Academy of Sciences, and University of Science and Technology of China, Hefei 230031, China
| | - Y Soh
- Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Yimin Xiong
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory of the Chinese Academy of Sciences, and University of Science and Technology of China, Hefei 230031, China
| | - Mingliang Tian
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory of the Chinese Academy of Sciences, and University of Science and Technology of China, 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 of the Chinese Academy of Sciences, and University of Science and Technology of China, Hefei 230031, China
- Institute of Physical Science and Information Technology, Anhui University, Hefei 230601, China
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22
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Ohara K, Zhang X, Chen Y, Wei Z, Ma Y, Xia J, Zhou Y, Liu X. Confinement and Protection of Skyrmions by Patterns of Modified Magnetic Properties. NANO LETTERS 2021; 21:4320-4326. [PMID: 33950694 DOI: 10.1021/acs.nanolett.1c00865] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Magnetic skyrmions are versatile topological excitations that can be used as nonvolatile information carriers. The confinement of skyrmions in channels is fundamental for any application based on the accumulation and transport of skyrmions. Here, we report a method that allows effective position control of skyrmions in designed channels by engineered energy barriers and wells, which is realized in a magnetic multilayer film by harnessing the boundaries of patterns with modified magnetic properties. We experimentally and computationally demonstrate that skyrmions can be attracted or repelled by the boundaries of areas with modified perpendicular magnetic anisotropy and Dzyaloshinskii-Moriya interaction. By fabricating square and stripe patterns with modified magnetic properties, we show the possibility of building reliable channels for confinement, accumulation, and transport of skyrmions, which effectively protect skyrmions from being destroyed at the device edges. Our results are useful for the design of spintronic applications using either static or dynamic skyrmions.
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Affiliation(s)
- Kentaro Ohara
- Department of Electrical and Computer Engineering, Shinshu University, 4-17-1 Wakasato, Nagano 380-8553, Japan
| | - Xichao Zhang
- Department of Electrical and Computer Engineering, Shinshu University, 4-17-1 Wakasato, Nagano 380-8553, Japan
| | - Yinling Chen
- Department of Electrical and Computer Engineering, Shinshu University, 4-17-1 Wakasato, Nagano 380-8553, Japan
| | - Zonhan Wei
- School of Mechanics and Engineering Science, Zhengzhou University, Zhengzhou 450001, China
| | - Yungui Ma
- State Key Lab of Modern Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Jing Xia
- 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
| | - Xiaoxi Liu
- Department of Electrical and Computer Engineering, Shinshu University, 4-17-1 Wakasato, Nagano 380-8553, Japan
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23
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Wu H, Nance J, Razavi SA, Lujan D, Dai B, Liu Y, He H, Cui B, Wu D, Wong K, Sobotkiewich K, Li X, Carman GP, Wang KL. Chiral Symmetry Breaking for Deterministic Switching of Perpendicular Magnetization by Spin-Orbit Torque. NANO LETTERS 2021; 21:515-521. [PMID: 33338380 DOI: 10.1021/acs.nanolett.0c03972] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Symmetry breaking is a characteristic to determine which branch of a bifurcation system follows upon crossing a critical point. Specifically, in spin-orbit torque (SOT) devices, a fundamental question arises: how can the symmetry of the perpendicular magnetic moment be broken by the in-plane spin polarization? Here, we show that the chiral symmetry breaking by the antisymmetric Dzyaloshinskii-Moriya interaction (DMI) can induce the deterministic SOT switching of the perpendicular magnetization. By introducing a gradient of saturation magnetization or magnetic anisotropy, the dynamic noncollinear spin textures are formed under the current-driven SOT, and thus, the chiral symmetry of these dynamic spin textures is broken by the DMI, resulting in the deterministic magnetization switching. We introduce a strategy to induce an out-of-plane (z) gradient of magnetic properties as a practical solution for the wafer-scale manufacture of SOT devices.
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Affiliation(s)
- Hao Wu
- Department of Electrical and Computer Engineering, and Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States
| | - John Nance
- Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, California 90095, United States
| | - Seyed Armin Razavi
- Department of Electrical and Computer Engineering, and Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States
| | - David Lujan
- Department of Physics, and Center for Complex Quantum Systems, The University of Texas at Austin, Texas 78712, United States
| | - Bingqian Dai
- Department of Electrical and Computer Engineering, and Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States
| | - Yuxiang Liu
- Department of Electrical and Computer Engineering, and Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States
| | - Haoran He
- Department of Electrical and Computer Engineering, and Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States
| | - Baoshan Cui
- Department of Electrical and Computer Engineering, and Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States
| | - Di Wu
- Department of Electrical and Computer Engineering, and Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States
| | - Kin Wong
- Department of Electrical and Computer Engineering, and Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States
| | - Kemal Sobotkiewich
- Department of Physics, and Center for Complex Quantum Systems, The University of Texas at Austin, Texas 78712, United States
| | - Xiaoqin Li
- Department of Physics, and Center for Complex Quantum Systems, The University of Texas at Austin, Texas 78712, United States
| | - Gregory P Carman
- Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, California 90095, United States
| | - Kang L Wang
- Department of Electrical and Computer Engineering, and Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States
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24
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Ba Y, Zhuang S, Zhang Y, Wang Y, Gao Y, Zhou H, Chen M, Sun W, Liu Q, Chai G, Ma J, Zhang Y, Tian H, Du H, Jiang W, Nan C, Hu JM, Zhao Y. Electric-field control of skyrmions in multiferroic heterostructure via magnetoelectric coupling. Nat Commun 2021; 12:322. [PMID: 33436572 PMCID: PMC7803786 DOI: 10.1038/s41467-020-20528-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 11/30/2020] [Indexed: 11/09/2022] Open
Abstract
Room-temperature skyrmions in magnetic multilayers are considered to be promising candidates for the next-generation spintronic devices. Several approaches have been developed to control skyrmions, but they either cause significant heat dissipation or require ultrahigh electric fields near the breakdown threshold. Here, we demonstrate electric-field control of skyrmions through strain-mediated magnetoelectric coupling in ferromagnetic/ferroelectric multiferroic heterostructures. We show the process of non-volatile creation of multiple skyrmions, reversible deformation and annihilation of a single skyrmion by performing magnetic force microscopy with in situ electric fields. Strain-induced changes in perpendicular magnetic anisotropy and interfacial Dzyaloshinskii–Moriya interaction strength are characterized experimentally. These experimental results, together with micromagnetic simulations, demonstrate that strain-mediated magnetoelectric coupling (via strain-induced changes in both the perpendicular magnetic anisotropy and interfacial Dzyaloshinskii–Moriya interaction is responsible for the observed electric-field control of skyrmions. Our work provides a platform to investigate electric-field control of skyrmions in multiferroic heterostructures and paves the way towards more energy-efficient skyrmion-based spintronics. The common approaches to control of skymions cause significant heat dissipation or require high electric fields near the breakdown threshold. Here, the authors demonstrate electric-field control of skyrmions through strain-mediated magnetoelectric coupling in multiferroic heterostructures.
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Affiliation(s)
- You Ba
- Department of Physics, State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing, 100084, China.,Frontier Science Center for Quantum Information, Tsinghua University, Beijing, 100084, China
| | - Shihao Zhuang
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Yike Zhang
- Department of Physics, State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing, 100084, China.,Frontier Science Center for Quantum Information, Tsinghua University, Beijing, 100084, China
| | - Yutong Wang
- Department of Physics, State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing, 100084, China.,Frontier Science Center for Quantum Information, Tsinghua University, Beijing, 100084, China
| | - Yang Gao
- Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou, 730000, China
| | - Hengan Zhou
- Department of Physics, State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing, 100084, China.,Frontier Science Center for Quantum Information, Tsinghua University, Beijing, 100084, China
| | - Mingfeng Chen
- School of Materials Science and Engineering, State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, Beijing, 100084, China
| | - Weideng Sun
- Department of Physics, State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing, 100084, China.,Frontier Science Center for Quantum Information, Tsinghua University, Beijing, 100084, China
| | - Quan Liu
- Department of Physics, State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing, 100084, China.,Frontier Science Center for Quantum Information, Tsinghua University, Beijing, 100084, China
| | - Guozhi Chai
- Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou, 730000, China
| | - Jing Ma
- School of Materials Science and Engineering, State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, Beijing, 100084, China
| | - Ying Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Huanfang Tian
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Haifeng Du
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory of Chinese Academy of Sciences, University of Science and Technology of China, Hefei, 230031, China
| | - Wanjun Jiang
- Department of Physics, State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing, 100084, China.,Frontier Science Center for Quantum Information, Tsinghua University, Beijing, 100084, China
| | - Cewen Nan
- School of Materials Science and Engineering, State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, Beijing, 100084, China
| | - Jia-Mian Hu
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA.
| | - Yonggang Zhao
- Department of Physics, State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing, 100084, China. .,Frontier Science Center for Quantum Information, Tsinghua University, Beijing, 100084, China.
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25
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Ran K, Liu Y, Guang Y, Burn DM, van der Laan G, Hesjedal T, Du H, Yu G, Zhang S. Creation of a Chiral Bobber Lattice in Helimagnet-Multilayer Heterostructures. PHYSICAL REVIEW LETTERS 2021; 126:017204. [PMID: 33480795 DOI: 10.1103/physrevlett.126.017204] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 10/26/2020] [Accepted: 11/20/2020] [Indexed: 06/12/2023]
Abstract
A chiral bobber is a localized three-dimensional magnetization configuration, terminated by a singularity. Chiral bobbers coexist with magnetic skyrmions in chiral magnets, lending themselves to new types of skyrmion-complementary bits of information. However, the on-demand creation of bobbers, as well as their direct observation remained elusive. Here, we introduce a new mechanism for creating a stable chiral bobber lattice state via the proximity of two skyrmion species with comparable size. This effect is experimentally demonstrated in a Cu_{2}OSeO_{3}/[Ta/CoFeB/MgO]_{4} heterostructure in which an exotic bobber lattice state emerges in the phase diagram of Cu_{2}OSeO_{3}. To unambiguously reveal the existence of the chiral bobber lattice state, we have developed a novel characterization technique, magnetic truncation rod analysis, which is based on resonant elastic x-ray scattering.
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Affiliation(s)
- Kejing Ran
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 200031, China
- ShanghaiTech Laboratory for Topological Physics, ShanghaiTech University, Shanghai 200031, China
| | - Yizhou Liu
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - Yao Guang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - David M Burn
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Gerrit van der Laan
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Thorsten Hesjedal
- Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - Haifeng Du
- The Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory and University of Science and Technology of China, Chinese Academy of Science (CAS), Hefei, Anhui 230031, China
| | - Guoqiang Yu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Shilei Zhang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 200031, China
- ShanghaiTech Laboratory for Topological Physics, ShanghaiTech University, Shanghai 200031, China
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26
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Coexistence of distinct skyrmion phases observed in hybrid ferromagnetic/ferrimagnetic multilayers. Nat Commun 2020; 11:6365. [PMID: 33311480 PMCID: PMC7733481 DOI: 10.1038/s41467-020-20025-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 11/11/2020] [Indexed: 11/11/2022] Open
Abstract
Materials hosting magnetic skyrmions at room temperature could enable compact and energetically-efficient storage such as racetrack memories, where information is coded by the presence/absence of skyrmions forming a moving chain through the device. The skyrmion Hall effect leading to their annihilation at the racetrack edges can be suppressed, for example, by antiferromagnetically-coupled skyrmions. However, avoiding modifications of the inter-skyrmion distances remains challenging. As a solution, a chain of bits could also be encoded by two different solitons, such as a skyrmion and a chiral bobber, with the limitation that it has solely been realized in B20-type materials at low temperatures. Here, we demonstrate that a hybrid ferro/ferri/ferromagnetic multilayer system can host two distinct skyrmion phases at room temperature, namely tubular and partial skyrmions. Furthermore, the tubular skyrmion can be converted into a partial skyrmion. Such systems may serve as a platform for designing memory applications using distinct skyrmion types. Topological spin textures are of technological interest due to their potential as a store of information. Here the authors experimentally demonstrate two distinct topological spin textures, tubular and incomplete skyrmions, and their mutual conversion in a ferromagnetic/ferromagnetic heterostructure.
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27
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Ognev AV, Kolesnikov AG, Kim YJ, Cha IH, Sadovnikov AV, Nikitov SA, Soldatov IV, Talapatra A, Mohanty J, Mruczkiewicz M, Ge Y, Kerber N, Dittrich F, Virnau P, Kläui M, Kim YK, Samardak AS. Magnetic Direct-Write Skyrmion Nanolithography. ACS NANO 2020; 14:14960-14970. [PMID: 33152236 DOI: 10.1021/acsnano.0c04748] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Magnetic skyrmions are stable spin textures with quasi-particle behavior and attract significant interest in fundamental and applied physics. The metastability of magnetic skyrmions at zero magnetic field is particularly important to enable, for instance, a skyrmion racetrack memory. Here, the results of the nucleation of stable skyrmions and formation of ordered skyrmion lattices by magnetic force microscopy in (Pt/CoFeSiB/W)n multilayers, exploiting the additive effect of the interfacial Dzyaloshinskii-Moriya interaction, are presented. The appropriate conditions under which skyrmion lattices are confined with a dense two-dimensional liquid phase are identified. A crucial parameter to control the skyrmion lattice characteristics and the number of scans resulting in the complete formation of a skyrmion lattice is the distance between two adjacent scanning lines of a magnetic force microscopy probe. The creation of skyrmion patterns with complex geometry is demonstrated, and the physical mechanism of direct magnetic writing of skyrmions is comprehended by micromagnetic simulations. This study shows a potential of a direct-write (maskless) skyrmion (topological) nanolithography with sub-100 nm resolution, where each skyrmion acts as a pixel in the final topological image.
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Affiliation(s)
- A V Ognev
- School of Natural Sciences, Far Eastern Federal University, Vladivostok 690950, Russia
| | - A G Kolesnikov
- School of Natural Sciences, Far Eastern Federal University, Vladivostok 690950, Russia
| | - Yong Jin Kim
- Department of Materials Science and Engineering, Korea University, Seoul 02841, Republic of Korea
| | - In Ho Cha
- Department of Materials Science and Engineering, Korea University, Seoul 02841, Republic of Korea
| | - A V Sadovnikov
- Laboratory "Metamaterials", Saratov State University, Saratov 410012, Russia
- Kotel'nikov Institute of Radioengineering and Electronics, Russian Academy of Sciences, Moscow 125009, Russia
| | - S A Nikitov
- Laboratory "Metamaterials", Saratov State University, Saratov 410012, Russia
- Kotel'nikov Institute of Radioengineering and Electronics, Russian Academy of Sciences, Moscow 125009, Russia
| | - I V Soldatov
- Leibniz Institute for Solid State and Material Research (IFW-Dresden), Dresden 01069, Germany
- Institute of Natural Sciences and Mathematic, Ural Federal University, Yekaterinburg 620075, Russia
| | - A Talapatra
- Indian Institute of Technology, Hyderabad 502285, India
| | - J Mohanty
- Indian Institute of Technology, Hyderabad 502285, India
| | - M Mruczkiewicz
- Institute of Electrical Engineering, SAS, Bratislava 841 04, Slovakia
- Centre for Advanced Materials Application (CEMEA), Slovak Academy of Sciences, Bratislava 845 11, Slovakia
| | - Y Ge
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Mainz 55128, Germany
| | - N Kerber
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Mainz 55128, Germany
| | - F Dittrich
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Mainz 55128, Germany
| | - P Virnau
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Mainz 55128, Germany
| | - M Kläui
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Mainz 55128, Germany
| | - Young Keun Kim
- Department of Materials Science and Engineering, Korea University, Seoul 02841, Republic of Korea
| | - A S Samardak
- School of Natural Sciences, Far Eastern Federal University, Vladivostok 690950, Russia
- National Research South Ural State University, Chelyabinsk 454080, Russia
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28
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Guang Y, Peng Y, Yan Z, Liu Y, Zhang J, Zeng X, Zhang S, Zhang S, Burn DM, Jaouen N, Wei J, Xu H, Feng J, Fang C, van der Laan G, Hesjedal T, Cui B, Zhang X, Yu G, Han X. Electron Beam Lithography of Magnetic Skyrmions. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2003003. [PMID: 32812294 DOI: 10.1002/adma.202003003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 06/27/2020] [Indexed: 05/08/2023]
Abstract
The emergence of magnetic skyrmions, topological spin textures, has aroused tremendous interest in studying the rich physics related to their topology. While skyrmions promise high-density and energy-efficient magnetic memory devices for information technology, the manifestation of their nontrivial topology through single skyrmions and ordered and disordered skyrmion lattices could also give rise to many fascinating physical phenomena, such as chiral magnon and skyrmion glass states. Therefore, generating skyrmions at designated locations on a large scale, while controlling the skyrmion patterns, is the key to advancing topological magnetism. Here, a new, yet general, approach to the "printing" of skyrmions with zero-field stability in arbitrary patterns on a massive scale in exchange-biased magnetic multilayers is presented. By exploiting the fact that the antiferromagnetic order can be reconfigured by local thermal excitations, a focused electron beam with a graphic pattern generator to "print" skyrmions is used, which is referred to as skyrmion lithography. This work provides a route to design arbitrary skyrmion patterns, thereby establishing the foundation for further exploration of topological magnetism.
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Affiliation(s)
- Yao Guang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yong Peng
- Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou University, Lanzhou, 730000, China
| | - Zhengren Yan
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yizhou Liu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Junwei Zhang
- Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou University, Lanzhou, 730000, China
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Xue Zeng
- School of Mathematics and Physics, Lanzhou Jiaotong University, Lanzhou, 730070, China
| | - Senfu Zhang
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Shilei Zhang
- ShanghaiTech Laboratory for Topological Physics, ShanghaiTech University, Shanghai, 201210, China
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - David M Burn
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, UK
| | - Nicolas Jaouen
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, Gif-sur-Yvette, 91192, France
| | - Jinwu Wei
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Hongjun Xu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Jiafeng Feng
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Chi Fang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Gerrit van der Laan
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, UK
| | - Thorsten Hesjedal
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford, OX1 3PU, UK
| | - Baoshan Cui
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Xixiang Zhang
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Guoqiang Yu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Xiufeng Han
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
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29
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Burn DM, Zhang SL, Yu GQ, Guang Y, Chen HJ, Qiu XP, van der Laan G, Hesjedal T. Depth-Resolved Magnetization Dynamics Revealed by X-Ray Reflectometry Ferromagnetic Resonance. PHYSICAL REVIEW LETTERS 2020; 125:137201. [PMID: 33034462 DOI: 10.1103/physrevlett.125.137201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 07/29/2020] [Accepted: 08/13/2020] [Indexed: 06/11/2023]
Abstract
Magnetic multilayers offer diverse opportunities for the development of ultrafast functional devices through advanced interface and layer engineering. Nevertheless, a method for determining their dynamic properties as a function of depth throughout such stacks has remained elusive. By probing the ferromagnetic resonance modes with element-selective soft x-ray resonant reflectivity, we gain access to the magnetization dynamics as a function of depth. Most notably, using reflectometry ferromagnetic resonance, we find a phase lag between the coupled ferromagnetic layers in [CoFeB/MgO/Ta]_{4} multilayers that is invisible to other techniques. The use of reflectometry ferromagnetic resonance enables the time-resolved and depth-resolved probing of the complex magnetization dynamics of a wide range of functional magnetic heterostructures with absorption edges in the soft x-ray wavelength regime.
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Affiliation(s)
- D M Burn
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - S L Zhang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 200031, China
- ShanghaiTech Laboratory for Topological Physics, ShanghaiTech University, Shanghai 200031, China
| | - G Q Yu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Y Guang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - H J Chen
- Shanghai Key Laboratory of Special Artificial Microstructure Materials and School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
| | - X P Qiu
- Shanghai Key Laboratory of Special Artificial Microstructure Materials and School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
| | - G van der Laan
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - T Hesjedal
- Department of Physics, Clarendon Laboratory, University of Oxford, Oxford OX1 3PU, United Kingdom
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30
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Tang J, Kong L, Wu Y, Wang W, Chen Y, Wang Y, Li J, Soh Y, Xiong Y, Tian M, Du H. Target Bubbles in Fe 3Sn 2 Nanodisks at Zero Magnetic Field. ACS NANO 2020; 14:10986-10992. [PMID: 32806036 DOI: 10.1021/acsnano.0c04036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We report a vortex-like magnetic configuration in uniaxial ferromagnet Fe3Sn2 nanodisks using differential phase contrast scanning transmission electron microscopy. This magnetic configuration is transferred from a conventional magnetic vortex using a zero-magnetic-field warming process and is characterized by a series of concentric cylinder domains. We termed them as "target bubbles" that are identified as three-dimensional depth-modulated magnetic objects in combination with numerical simulations. Target bubbles have room-temperature stability even at zero magnetic field and multiple stable magnetic configurations. These advantages render the target bubble an ideal bit to be an information carrier and can advance magnetic target bubbles toward functionalities in the long term by incorporating emergent degrees of freedom and purely electrically controllable magnetism.
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Affiliation(s)
- Jin Tang
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory of Chinese Academy of Sciences, and University of Science and Technology of China, Hefei, 230031, China
| | - Lingyao Kong
- School of Physics and Materials Science, Anhui University, Hefei, 230601, China
| | - Yaodong Wu
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory of Chinese Academy of Sciences, and University of Science and Technology of China, Hefei, 230031, China
- Universities Joint Key Laboratory of Photoelectric Detection Science and Technology in Anhui Province, Hefei Normal University, Hefei, 230601, China
| | - Weiwei Wang
- Institutes of Physical Science and Information Technology, Anhui University, Hefei, 230601, China
| | - Yutao Chen
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory of Chinese Academy of Sciences, and University of Science and Technology of China, Hefei, 230031, China
| | - Yihao Wang
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory of Chinese Academy of Sciences, and University of Science and Technology of China, Hefei, 230031, China
| | - Junbo Li
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory of Chinese Academy of Sciences, and University of Science and Technology of China, Hefei, 230031, China
| | - Y Soh
- Paul Scherrer Institute, 5232, Villigen, Switzerland
| | - Yimin Xiong
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory of Chinese Academy of Sciences, and University of Science and Technology of China, Hefei, 230031, China
| | - Mingliang Tian
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory of Chinese Academy of Sciences, and University of Science and Technology of China, 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 of Chinese Academy of Sciences, and University of Science and Technology of China, Hefei, 230031, China
- Institutes of Physical Science and Information Technology, Anhui University, Hefei, 230601, China
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31
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Zhang J, Zhang Y, Gao Y, Zhao G, Qiu L, Wang K, Dou P, Peng W, Zhuang Y, Wu Y, Yu G, Zhu Z, Zhao Y, Guo Y, Zhu T, Cai J, Shen B, Wang S. Magnetic Skyrmions in a Hall Balance with Interfacial Canted Magnetizations. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1907452. [PMID: 32743868 DOI: 10.1002/adma.201907452] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 06/29/2020] [Indexed: 06/11/2023]
Abstract
Magnetic skyrmions are attracting interest as efficient information-storage devices with low energy consumption, and have been experimentally and theoretically investigated in multilayers including ferromagnets, ferrimagnets, and antiferromagnets. The 3D spin texture of skyrmions demonstrated in ferromagnetic multilayers provides a powerful pathway for understanding the stabilization of ferromagnetic skyrmions. However, the manipulation mechanism of skyrmions in antiferromagnets is still lacking. A Hall balance with a ferromagnet/insulating spacer/ferromagnet structure is considered to be a promising candidate to study skyrmions in synthetic antiferromagnets. Here, high-density Néel-type skyrmions are experimentally observed at zero field and room temperature by Lorentz transmission electron microscopy in a Hall balance (core structure [Co/Pt]n /NiO/[Co/Pt]n ) with interfacial canted magnetizations because of interlayer ferromagnetic/antiferromagnetic coupling between top and bottom [Co/Pt]n multilayers, where the Co layers in [Co/Pt]n are always ferromagnetically coupled. Micromagnetic simulations show that the generation and density of skyrmions are strongly dependent on interlayer exchange coupling (IEC) and easy-axis orientation. Direct experimental evidence of skyrmions in synthetic antiferromagnets is provided, suggesting that the proposed approach offers a promising alternative mechanism for room-temperature spintronics.
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Affiliation(s)
- Jingyan Zhang
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Ying Zhang
- State Key Laboratory of Magnetism, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Yang Gao
- State Key Laboratory of Magnetism, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Guoping Zhao
- College of Physics and Electronic Engineering, Sichuan Normal University, Chengdu, 610068, China
| | - Lei Qiu
- College of Physics and Electronic Engineering, Sichuan Normal University, Chengdu, 610068, China
| | - Kaiyou Wang
- State Key Laboratory for Superlattices and Microstructures Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China
| | - Pengwei Dou
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Wenlin Peng
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Yuan Zhuang
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Yanfei Wu
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Guoqiang Yu
- State Key Laboratory of Magnetism, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Zhaozhao Zhu
- State Key Laboratory of Magnetism, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Yunchi Zhao
- State Key Laboratory of Magnetism, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Yaqin Guo
- State Key Laboratory of Magnetism, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Tao Zhu
- State Key Laboratory of Magnetism, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Jianwang Cai
- State Key Laboratory of Magnetism, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Baogen Shen
- State Key Laboratory of Magnetism, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Shouguo Wang
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing, 100083, China
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32
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Olleros-Rodríguez P, Guerrero R, Camarero J, Chubykalo-Fesenko O, Perna P. Intrinsic Mixed Bloch-Néel Character and Chirality of Skyrmions in Asymmetric Epitaxial Trilayers. ACS APPLIED MATERIALS & INTERFACES 2020; 12:25419-25427. [PMID: 32401480 DOI: 10.1021/acsami.0c04661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Recent advances in the stabilization and manipulation of chiral magnetization configurations in systems consisting of alternating atomic layers of ferromagnetic and nonmagnetic materials hold promise for innovation in spintronics technology. The low dimensionality of the systems promotes spin orbit driven interfacial effects like antisymmetric Dzyaloshinskii-Moriya interactions (DMI) and surface magnetic anisotropy, whose relative strengths may be tuned to achieve stable nanometer sized magnetic objects with fixed chirality. While in most of the cases this is obtained by engineering complex multilayers stacks in which interlayer dipolar fields become important, we consider here a simple epitaxial trilayer in which a ferromagnet, with variable thickness, is embedded between a heavy metal and graphene. The latter enhances the perpendicular magnetic anisotropy of the system, promotes a Rashba-type DMI, and can sustain very long spin diffusion lengths. We use a layer-resolved micromagnetic model to describe the magnetization textures and their chirality. Our results demonstrate that for Co thicknesses larger than 3.6 nm, a skyrmion having an intrinsic mixed Bloch-Néel character is stabilized in the entire (single) Co layer.
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Affiliation(s)
| | - Ruben Guerrero
- IMDEA Nanociencia, c/Faraday 9, Campus de Cantoblanco, 28049 Madrid, Spain
| | - Julio Camarero
- IMDEA Nanociencia, c/Faraday 9, Campus de Cantoblanco, 28049 Madrid, Spain
- Departamento de Física de la Materia Condensada, Instituto "Nicolas Cabrera" and Condensed Matter Physics Center (IFIMAC), Universidad Autonoma de Madrid, Campus de Cantoblanco, 28049 Madrid, Spain
| | | | - Paolo Perna
- IMDEA Nanociencia, c/Faraday 9, Campus de Cantoblanco, 28049 Madrid, Spain
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33
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Lepadatu S. Effect of inter-layer spin diffusion on skyrmion motion in magnetic multilayers. Sci Rep 2019; 9:9592. [PMID: 31270384 PMCID: PMC6610116 DOI: 10.1038/s41598-019-46091-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 06/21/2019] [Indexed: 12/01/2022] Open
Abstract
It is well known that skyrmions can be driven using spin-orbit torques due to the spin-Hall effect. Here we show an additional contribution in multilayered stacks arises from vertical spin currents due to inter-layer diffusion of a spin accumulation generated at a skyrmion. This additional interfacial spin torque is similar in form to the in-plane spin transfer torque, but is significantly enhanced in ultra-thin films and acts in the opposite direction to the electron flow. The combination of this diffusive spin torque and the spin-orbit torque results in skyrmion motion which helps to explain the observation of small skyrmion Hall angles even with moderate magnetisation damping values. Further, the effect of material imperfections on threshold currents and skyrmion Hall angle is also investigated. Topographical surface roughness, as small as a single monolayer variation, is shown to be an important contributing factor in ultra-thin films, resulting in good agreement with experimental observations.
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Affiliation(s)
- Serban Lepadatu
- Jeremiah Horrocks Institute for Mathematics, Physics and Astronomy, University of Central Lancashire, Preston, PR1 2HE, UK.
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