1
|
Birch MT, Yasin FS, Litzius K, Powalla L, Wintz S, Schulz F, Kossak AE, Weigand M, Scholz T, Lotsch BV, Schütz G, Yu XZ, Burghard M. Influence of Magnetic Sublattice Ordering on Skyrmion Bubble Stability in 2D Magnet Fe 5GeTe 2. ACS NANO 2024; 18:18246-18256. [PMID: 38975730 PMCID: PMC11256745 DOI: 10.1021/acsnano.4c00853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 06/20/2024] [Accepted: 06/21/2024] [Indexed: 07/09/2024]
Abstract
The realization of above room-temperature ferromagnetism in the two-dimensional (2D) magnet Fe5GeTe2 represents a major advance for the use of van der Waals (vdW) materials in practical spintronic applications. In particular, observations of magnetic skyrmions and related states within exfoliated flakes of this material provide a pathway to the fine-tuning of topological spin textures via 2D material heterostructure engineering. However, there are conflicting reports as to the nature of the magnetic structures in Fe5GeTe2. The matter is further complicated by the study of two types of Fe5GeTe2 crystals with markedly different structural and magnetic properties, distinguished by their specific fabrication procedure: whether they are slowly cooled or rapidly quenched from the growth temperature. In this work, we combine X-ray and electron microscopy to observe the formation of magnetic stripe domains, skyrmion-like type-I, and topologically trivial type-II bubbles, within exfoliated flakes of Fe5GeTe2. The results reveal the influence of the magnetic ordering of the Fe1 sublattice below 150 K, which dramatically alters the magnetocrystalline anisotropy and leads to a complex magnetic phase diagram and a sudden change of the stability of the magnetic textures. In addition, we highlight the significant differences in the magnetic structures intrinsic to slow-cooled and quenched Fe5GeTe2 flakes.
Collapse
Affiliation(s)
- Max T. Birch
- Max
Planck Institute for Intelligent Systems, Heisenbergstraße 3, Stuttgart 70569, Germany
- RIKEN
Center for Emergent Matter Science, Hirosawa 2-1, Wako 351-0198, Japan
| | - Fehmi S. Yasin
- RIKEN
Center for Emergent Matter Science, Hirosawa 2-1, Wako 351-0198, Japan
- Center
for Nanophase Materials Sciences, Oak Ridge
National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Kai Litzius
- Max
Planck Institute for Intelligent Systems, Heisenbergstraße 3, Stuttgart 70569, Germany
| | - Lukas Powalla
- Max
Planck Institute for Solid State Research, Heisenbergstraße 1, Stuttgart 70569, Germany
| | - Sebastian Wintz
- Helmholtz-Zentrum
Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, Berlin 14109, Germany
| | - Frank Schulz
- Max
Planck Institute for Intelligent Systems, Heisenbergstraße 3, Stuttgart 70569, Germany
| | - Alexander E. Kossak
- Department
of Materials Science and Engineering, Massachusetts
Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Markus Weigand
- Helmholtz-Zentrum
Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, Berlin 14109, Germany
| | - Tanja Scholz
- Max
Planck Institute for Solid State Research, Heisenbergstraße 1, Stuttgart 70569, Germany
| | - Bettina V. Lotsch
- Max
Planck Institute for Solid State Research, Heisenbergstraße 1, Stuttgart 70569, Germany
- University
of Munich (LMU), Butenandtstraße
5-13 (Haus D), München 81377, Germany
| | - Gisela Schütz
- Max
Planck Institute for Intelligent Systems, Heisenbergstraße 3, Stuttgart 70569, Germany
| | - Xiuzhen Z. Yu
- RIKEN
Center for Emergent Matter Science, Hirosawa 2-1, Wako 351-0198, Japan
| | - Marko Burghard
- Max
Planck Institute for Solid State Research, Heisenbergstraße 1, Stuttgart 70569, Germany
| |
Collapse
|
2
|
Zhang C, Jiang Z, Jiang J, He W, Zhang J, Hu F, Zhao S, Yang D, Liu Y, Peng Y, Yang H, Yang H. Above-room-temperature chiral skyrmion lattice and Dzyaloshinskii-Moriya interaction in a van der Waals ferromagnet Fe 3-xGaTe 2. Nat Commun 2024; 15:4472. [PMID: 38796498 PMCID: PMC11127993 DOI: 10.1038/s41467-024-48799-9] [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: 09/23/2023] [Accepted: 05/14/2024] [Indexed: 05/28/2024] Open
Abstract
Skyrmions in existing 2D van der Waals (vdW) materials have primarily been limited to cryogenic temperatures, and the underlying physical mechanism of the Dzyaloshinskii-Moriya interaction (DMI), a crucial ingredient for stabilizing chiral skyrmions, remains inadequately explored. Here, we report the observation of Néel-type skyrmions in a vdW ferromagnet Fe3-xGaTe2 above room temperature. Contrary to previous assumptions of centrosymmetry in Fe3-xGaTe2, the atomic-resolution scanning transmission electron microscopy reveals that the off-centered FeΙΙ atoms break the spatial inversion symmetry, rendering it a polar metal. First-principles calculations further elucidate that the DMI primarily stems from the Te sublayers through the Fert-Lévy mechanism. Remarkably, the chiral skyrmion lattice in Fe3-xGaTe2 can persist up to 330 K at zero magnetic field, demonstrating superior thermal stability compared to other known skyrmion vdW magnets. This work provides valuable insights into skyrmionics and presents promising prospects for 2D material-based skyrmion devices operating beyond room temperature.
Collapse
Affiliation(s)
- Chenhui Zhang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, Singapore
| | - Ze Jiang
- School of Materials and Energy and Electron Microscopy Centre of Lanzhou University, Lanzhou University, Lanzhou, 730000, China
| | - Jiawei Jiang
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Wa He
- School of Materials and Energy and Electron Microscopy Centre of Lanzhou University, Lanzhou University, Lanzhou, 730000, China
| | - Junwei Zhang
- School of Materials and Energy and Electron Microscopy Centre of Lanzhou University, Lanzhou University, Lanzhou, 730000, China
| | - Fanrui Hu
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, Singapore
| | - Shishun Zhao
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, Singapore
| | - Dongsheng Yang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, Singapore
| | - Yakun Liu
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, Singapore
| | - Yong Peng
- School of Materials and Energy and Electron Microscopy Centre of Lanzhou University, Lanzhou University, Lanzhou, 730000, China.
| | - Hongxin Yang
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China.
- Center for Quantum Matter, School of Physics, Zhejiang University, Hangzhou, 310058, China.
| | - Hyunsoo Yang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, Singapore.
| |
Collapse
|
3
|
Zhang H, Shao YT, Chen X, Zhang B, Wang T, Meng F, Xu K, Meisenheimer P, Chen X, Huang X, Behera P, Husain S, Zhu T, Pan H, Jia Y, Settineri N, Giles-Donovan N, He Z, Scholl A, N'Diaye A, Shafer P, Raja A, Xu C, Martin LW, Crommie MF, Yao J, Qiu Z, Majumdar A, Bellaiche L, Muller DA, Birgeneau RJ, Ramesh R. Spin disorder control of topological spin texture. Nat Commun 2024; 15:3828. [PMID: 38714653 PMCID: PMC11076609 DOI: 10.1038/s41467-024-47715-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Accepted: 04/10/2024] [Indexed: 05/10/2024] Open
Abstract
Stabilization of topological spin textures in layered magnets has the potential to drive the development of advanced low-dimensional spintronics devices. However, achieving reliable and flexible manipulation of the topological spin textures beyond skyrmion in a two-dimensional magnet system remains challenging. Here, we demonstrate the introduction of magnetic iron atoms between the van der Waals gap of a layered magnet, Fe3GaTe2, to modify local anisotropic magnetic interactions. Consequently, we present direct observations of the order-disorder skyrmion lattices transition. In addition, non-trivial topological solitons, such as skyrmioniums and skyrmion bags, are realized at room temperature. Our work highlights the influence of random spin control of non-trivial topological spin textures.
Collapse
Affiliation(s)
- Hongrui Zhang
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA.
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
| | - Yu-Tsun Shao
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA, 90089, USA
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, 14853, USA
| | - Xiang Chen
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
- Department of Physics, University of California, Berkeley, CA, 94720, USA.
- Center for Neutron Science and Technology, School of Physics, Sun Yat-Sen University, Guangzhou, Guangdong, 510275, China.
| | - Binhua Zhang
- Key Laboratory of Computational Physical Sciences (Ministry of Education), Institute of Computational Physical Sciences, State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai, 200433, China
- Shanghai Qi Zhi Institute, Shanghai, 200030, China
| | - Tianye Wang
- Department of Physics, University of California, Berkeley, CA, 94720, USA
| | - Fanhao Meng
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Kun Xu
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA
| | - Peter Meisenheimer
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Xianzhe Chen
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Xiaoxi Huang
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Piush Behera
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Sajid Husain
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Tiancong Zhu
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Physics, University of California, Berkeley, CA, 94720, USA
| | - Hao Pan
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Yanli Jia
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Nick Settineri
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | | | - Zehao He
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Physics, University of California, Berkeley, CA, 94720, USA
| | - Andreas Scholl
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Alpha N'Diaye
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Padraic Shafer
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Archana Raja
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Changsong Xu
- Key Laboratory of Computational Physical Sciences (Ministry of Education), Institute of Computational Physical Sciences, State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai, 200433, China.
- Shanghai Qi Zhi Institute, Shanghai, 200030, China.
| | - Lane W Martin
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Materials Science and NanoEngineering, Rice University, Houston, TX, 77005, USA
- Department of Chemistry, Rice University, Houston, TX, 77005, USA
- Department of Physics and Astronomy, Rice University, Houston, TX, 77005, USA
- Rice Advanced Materials Institute, Rice University, Houston, TX, 77005, USA
| | - Michael F Crommie
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Physics, University of California, Berkeley, CA, 94720, USA
| | - Jie Yao
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Ziqiang Qiu
- Department of Physics, University of California, Berkeley, CA, 94720, USA
| | - Arun Majumdar
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA
| | - Laurent Bellaiche
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, AR, 72701, USA
| | - David A Muller
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, 14853, USA
- Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, NY, 14853, USA
| | - Robert J Birgeneau
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Physics, University of California, Berkeley, CA, 94720, USA
| | - Ramamoorthy Ramesh
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA.
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
- Department of Physics, University of California, Berkeley, CA, 94720, USA.
- Department of Materials Science and NanoEngineering, Rice University, Houston, TX, 77005, USA.
- Department of Physics and Astronomy, Rice University, Houston, TX, 77005, USA.
- Rice Advanced Materials Institute, Rice University, Houston, TX, 77005, USA.
| |
Collapse
|
4
|
Li Z, Yin Q, Lv W, Shen J, Wang S, Zhao T, Cai J, Lei H, Lin SZ, Zhang Y, Shen B. Electron-Assisted Generation and Straight Movement of Skyrmion Bubble in Kagome TbMn 6Sn 6. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2309538. [PMID: 38366361 DOI: 10.1002/adma.202309538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 12/31/2023] [Indexed: 02/18/2024]
Abstract
Topological magnetic textures are promising candidates as binary data units for the next-generation memory device. The precise generation and convenient control of nontrivial spin topology at zero field near room temperature endows the critical advantages in skyrmionic devices but is not simultaneously integrated into one material. Here, in the Kagome plane of quantum TbMn6Sn6, the expedient generation of the skyrmion bubbles in versatile forms of lattice, chain, and isolated one by converging the electron beam, where the electron intensity gradient contributes to the dynamic generation from local anisotropy variation near spin reorientation transition (SRT) is reported. Encouragingly, by utilizing the dynamic shift of the SRT domain interface, the straight movement is actualized with the skyrmion bubble slave to the SRT domain interface forming an elastic composite object, avoiding the usual deflection from the skyrmion Hall effect. The critical contribution of the SRT domain interface via conveniently electron-assisted heating is further theoretically validated in micromagnetic simulation, highlighting the compatible application possibility in advanced devices.
Collapse
Affiliation(s)
- Zhuolin Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
| | - Qiangwei Yin
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & MicroNano Devices, Renmin University of China, Beijing, 100872, China
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing, 100872, China
| | - Wenxin Lv
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & MicroNano Devices, Renmin University of China, Beijing, 100872, China
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing, 100872, China
| | - Jun Shen
- Department of Energy and Power Engineering, School of Mechanical Engineering, Beijing Institute of Technology, Beijing, 100081, China
| | - Shouguo Wang
- Anhui Key Laboratory of Magnetic Functional Materials and Devices, School of Materials Science and Engineering, Anhui University, Hefei, 230601, China
| | - Tongyun Zhao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
| | - Jianwang Cai
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
| | - Hechang Lei
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & MicroNano Devices, Renmin University of China, Beijing, 100872, China
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing, 100872, China
| | - Shi-Zeng Lin
- Theoretical Division and Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico, 87545, USA
| | - Ying Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
- Open Access Research Infrastrucure, Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Baogen Shen
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
- Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang, 315201, China
| |
Collapse
|
5
|
Jani H, Harrison J, Hooda S, Prakash S, Nandi P, Hu J, Zeng Z, Lin JC, Godfrey C, Omar GJ, Butcher TA, Raabe J, Finizio S, Thean AVY, Ariando A, Radaelli PG. Spatially reconfigurable antiferromagnetic states in topologically rich free-standing nanomembranes. NATURE MATERIALS 2024; 23:619-626. [PMID: 38374414 PMCID: PMC11068574 DOI: 10.1038/s41563-024-01806-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Accepted: 01/11/2024] [Indexed: 02/21/2024]
Abstract
Antiferromagnets hosting real-space topological textures are promising platforms to model fundamental ultrafast phenomena and explore spintronics. However, they have only been epitaxially fabricated on specific symmetry-matched substrates, thereby preserving their intrinsic magneto-crystalline order. This curtails their integration with dissimilar supports, restricting the scope of fundamental and applied investigations. Here we circumvent this limitation by designing detachable crystalline antiferromagnetic nanomembranes of α-Fe2O3. First, we show-via transmission-based antiferromagnetic vector mapping-that flat nanomembranes host a spin-reorientation transition and rich topological phenomenology. Second, we exploit their extreme flexibility to demonstrate the reconfiguration of antiferromagnetic states across three-dimensional membrane folds resulting from flexure-induced strains. Finally, we combine these developments using a controlled manipulator to realize the strain-driven non-thermal generation of topological textures at room temperature. The integration of such free-standing antiferromagnetic layers with flat/curved nanostructures could enable spin texture designs via magnetoelastic/geometric effects in the quasi-static and dynamical regimes, opening new explorations into curvilinear antiferromagnetism and unconventional computing.
Collapse
Affiliation(s)
- Hariom Jani
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, UK.
- Department of Physics, National University of Singapore, Singapore, Singapore.
| | - Jack Harrison
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, UK
| | - Sonu Hooda
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Saurav Prakash
- Department of Physics, National University of Singapore, Singapore, Singapore
| | - Proloy Nandi
- Department of Physics, National University of Singapore, Singapore, Singapore
| | - Junxiong Hu
- Department of Physics, National University of Singapore, Singapore, Singapore.
| | - Zhiyang Zeng
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, UK
| | - Jheng-Cyuan Lin
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, UK
| | - Charles Godfrey
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, UK
| | - Ganesh Ji Omar
- Department of Physics, National University of Singapore, Singapore, Singapore
| | - Tim A Butcher
- Swiss Light Source, Paul Scherrer Institut, Villigen, Switzerland
| | - Jörg Raabe
- Swiss Light Source, Paul Scherrer Institut, Villigen, Switzerland
| | - Simone Finizio
- Swiss Light Source, Paul Scherrer Institut, Villigen, Switzerland.
| | - Aaron Voon-Yew Thean
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
- Integrative Sciences and Engineering Programme, National University of Singapore, Singapore, Singapore
| | - A Ariando
- Department of Physics, National University of Singapore, Singapore, Singapore.
- Integrative Sciences and Engineering Programme, National University of Singapore, Singapore, Singapore.
| | - Paolo G Radaelli
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, UK.
| |
Collapse
|
6
|
Pham VT, Sisodia N, Di Manici I, Urrestarazu-Larrañaga J, Bairagi K, Pelloux-Prayer J, Guedas R, Buda-Prejbeanu LD, Auffret S, Locatelli A, Menteş TO, Pizzini S, Kumar P, Finco A, Jacques V, Gaudin G, Boulle O. Fast current-induced skyrmion motion in synthetic antiferromagnets. Science 2024; 384:307-312. [PMID: 38635712 DOI: 10.1126/science.add5751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 03/14/2024] [Indexed: 04/20/2024]
Abstract
Magnetic skyrmions are topological magnetic textures that hold great promise as nanoscale bits of information in memory and logic devices. Although room-temperature ferromagnetic skyrmions and their current-induced manipulation have been demonstrated, their velocity has been limited to about 100 meters per second. In addition, their dynamics are perturbed by the skyrmion Hall effect, a motion transverse to the current direction caused by the skyrmion topological charge. Here, we show that skyrmions in compensated synthetic antiferromagnets can be moved by current along the current direction at velocities of up to 900 meters per second. This can be explained by the cancellation of the net topological charge leading to a vanishing skyrmion Hall effect. Our results open an important path toward the realization of logic and memory devices based on the fast manipulation of skyrmions in tracks.
Collapse
Affiliation(s)
- Van Tuong Pham
- Université Grenoble Alpes, CNRS, CEA, SPINTEC, 38054 Grenoble, France
- Université Grenoble Alpes, CNRS, Institut Néel, 38042 Grenoble, France
| | - Naveen Sisodia
- Université Grenoble Alpes, CNRS, CEA, SPINTEC, 38054 Grenoble, France
- Department of Physics, Indian Institute of Technology Gandhinagar, Gandhinagar 382355, Gujarat, India
| | - Ilaria Di Manici
- Université Grenoble Alpes, CNRS, CEA, SPINTEC, 38054 Grenoble, France
| | | | - Kaushik Bairagi
- Université Grenoble Alpes, CNRS, CEA, SPINTEC, 38054 Grenoble, France
| | | | - Rodrigo Guedas
- Université Grenoble Alpes, CNRS, CEA, SPINTEC, 38054 Grenoble, France
- Instituto de Sistemas Optoelectrónicos y Microtecnología (ISOM), Universidad Politécnica de Madrid, 28040 Madrid, Spain
| | | | - Stéphane Auffret
- Université Grenoble Alpes, CNRS, CEA, SPINTEC, 38054 Grenoble, France
| | - Andrea Locatelli
- Elettra-Sincrotrone Trieste S.C.p.A., 34149 Basovizza, Trieste, Italy
| | | | - Stefania Pizzini
- Université Grenoble Alpes, CNRS, Institut Néel, 38042 Grenoble, France
| | - Pawan Kumar
- Laboratoire Charles Coulomb, Université de Montpellier, CNRS, 34095 Montpellier, France
| | - Aurore Finco
- Laboratoire Charles Coulomb, Université de Montpellier, CNRS, 34095 Montpellier, France
| | - Vincent Jacques
- Laboratoire Charles Coulomb, Université de Montpellier, CNRS, 34095 Montpellier, France
| | - Gilles Gaudin
- Université Grenoble Alpes, CNRS, CEA, SPINTEC, 38054 Grenoble, France
| | - Olivier Boulle
- Université Grenoble Alpes, CNRS, CEA, SPINTEC, 38054 Grenoble, France
| |
Collapse
|
7
|
Aceves Rodriguez UA, Guimarães F, Brinker S, Lounis S. Magnetic exchange interactions at the proximity of a superconductor. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:295801. [PMID: 38471158 DOI: 10.1088/1361-648x/ad32de] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 03/12/2024] [Indexed: 03/14/2024]
Abstract
Interfacing magnetism with superconductivity gives rise to a wonderful playground for intertwining key degrees of freedom: Cooper pairs, spin, charge, and spin-orbit interaction, from which emerge a wealth of exciting phenomena, fundamental in the nascent field of superconducting spinorbitronics and topological quantum technologies. Magnetic exchange interactions (MEIs), being isotropic or chiral such as the Dzyaloshinskii-Moriya interactions, are vital in establishing the magnetic behavior at these interfaces as well as in dictating not only complex transport phenomena, but also the manifestation of topologically trivial or non-trivial objects. Here, we propose a methodology enabling the extraction of the tensor of MEI from electronic structure simulations accounting for superconductivity. We apply our scheme to the case of a Mn layer deposited on Nb(110) surface and explore proximity-induced impact on the MEI. The latter are weakly modified by a realistic electron-phonon coupling. However, tuning the superconducting order parameter, we unveil potential change of the magnetic order accompanied with chirality switching, as induced by the interplay of spin-orbit interaction and Cooper pairing. Owing to its simple formulation, our methodology can be readily implemented in state-of-the-art frameworks capable of tackling superconductivity and magnetism. We thus foresee implications in the simulations and prediction of topological superconducting bits as well as of cryogenic superconducting hybrid devices involving magnetic units.
Collapse
Affiliation(s)
- Uriel A Aceves Rodriguez
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich & JARA, 52425 Jülich, Germany
- Faculty of Physics & CENIDE, University of Duisburg-Essen, 47053 Duisburg, Germany
| | - Filipe Guimarães
- Jülich Supercomputing Centre, Forschungszentrum Jülich & JARA, 52425 Jülich, Germany
| | - Sascha Brinker
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich & JARA, 52425 Jülich, Germany
| | - Samir Lounis
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich & JARA, 52425 Jülich, Germany
- Faculty of Physics & CENIDE, University of Duisburg-Essen, 47053 Duisburg, Germany
| |
Collapse
|
8
|
Bhukta M, Dohi T, Bharadwaj VK, Zarzuela R, Syskaki MA, Foerster M, Niño MA, Sinova J, Frömter R, Kläui M. Homochiral antiferromagnetic merons, antimerons and bimerons realized in synthetic antiferromagnets. Nat Commun 2024; 15:1641. [PMID: 38409221 PMCID: PMC10897388 DOI: 10.1038/s41467-024-45375-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 01/23/2024] [Indexed: 02/28/2024] Open
Abstract
The ever-growing demand for device miniaturization and energy efficiency in data storage and computing technology has prompted a shift towards antiferromagnetic topological spin textures as information carriers. This shift is primarily owing to their negligible stray fields, leading to higher possible device density and potentially ultrafast dynamics. We realize in this work such chiral in-plane topological antiferromagnetic spin textures namely merons, antimerons, and bimerons in synthetic antiferromagnets by concurrently engineering the effective perpendicular magnetic anisotropy, the interlayer exchange coupling, and the magnetic compensation ratio. We demonstrate multimodal vector imaging of the three-dimensional Néel order parameter, revealing the topology of those spin textures and a globally well-defined chirality, which is a crucial requirement for controlled current-induced dynamics. Our analysis reveals that the interplay between interlayer exchange and interlayer magnetic dipolar interactions plays a key role to significantly reduce the critical strength of the Dzyaloshinskii-Moriya interaction required to stabilize topological spin textures, such as antiferromagnetic merons, in synthetic antiferromagnets, making them a promising platform for next-generation spintronics applications.
Collapse
Affiliation(s)
- Mona Bhukta
- Institute of Physics, Johannes Gutenberg-University Mainz, 55099, Mainz, Germany
| | - Takaaki Dohi
- Institute of Physics, Johannes Gutenberg-University Mainz, 55099, Mainz, Germany.
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba, Sendai, 980-8577, Japan.
| | | | - Ricardo Zarzuela
- Institute of Physics, Johannes Gutenberg-University Mainz, 55099, Mainz, Germany
| | - Maria-Andromachi Syskaki
- Institute of Physics, Johannes Gutenberg-University Mainz, 55099, Mainz, Germany
- Singulus Technologies AG, Hanauer Landstrasse 107, 63796, Kahl am Main, Germany
| | - Michael Foerster
- ALBA Synchrotron Light Facility, 08290, Cerdanyola del Vallés, Barcelona, Spain
| | - Miguel Angel Niño
- ALBA Synchrotron Light Facility, 08290, Cerdanyola del Vallés, Barcelona, Spain
| | - Jairo Sinova
- Institute of Physics, Johannes Gutenberg-University Mainz, 55099, Mainz, Germany
| | - Robert Frömter
- Institute of Physics, Johannes Gutenberg-University Mainz, 55099, Mainz, Germany.
| | - Mathias Kläui
- Institute of Physics, Johannes Gutenberg-University Mainz, 55099, Mainz, Germany.
| |
Collapse
|
9
|
Kalz E, Vuijk HD, Sommer JU, Metzler R, Sharma A. Oscillatory Force Autocorrelations in Equilibrium Odd-Diffusive Systems. PHYSICAL REVIEW LETTERS 2024; 132:057102. [PMID: 38364150 DOI: 10.1103/physrevlett.132.057102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 07/19/2023] [Accepted: 11/28/2023] [Indexed: 02/18/2024]
Abstract
The force autocorrelation function (FACF), a concept of fundamental interest in statistical mechanics, encodes the effect of interactions on the dynamics of a tagged particle. In equilibrium, the FACF is believed to decay monotonically in time, which is a signature of slowing down of the dynamics of the tagged particle due to interactions. Here, we analytically show that in odd-diffusive systems, which are characterized by a diffusion tensor with antisymmetric elements, the FACF can become negative and even exhibit temporal oscillations. We also demonstrate that, despite the isotropy, the knowledge of FACF alone is not sufficient to describe the dynamics: the full autocorrelation tensor is required and contains an antisymmetric part. These unusual properties translate into enhanced dynamics of the tagged particle quantified via the self-diffusion coefficient that, remarkably, increases due to particle interactions.
Collapse
Affiliation(s)
- Erik Kalz
- University of Potsdam, Institute of Physics and Astronomy, D-14476 Potsdam, Germany
| | - Hidde Derk Vuijk
- University of Augsburg, Institute of Physics, D-86159 Augsburg, Germany
| | - Jens-Uwe Sommer
- Leibniz-Institute for Polymer Research, Institute Theory of Polymers, D-01069 Dresden, Germany
- Technical University of Dresden, Institute for Theoretical Physics, D-01069 Dresden, Germany
- Technical University of Dresden, Cluster of Excellence Physics of Life, D-01069 Dresden, Germany
| | - Ralf Metzler
- University of Potsdam, Institute of Physics and Astronomy, D-14476 Potsdam, Germany
- Asia Pacific Centre for Theoretical Physics, KR-37673 Pohang, Republic of Korea
| | - Abhinav Sharma
- University of Augsburg, Institute of Physics, D-86159 Augsburg, Germany
- Leibniz-Institute for Polymer Research, Institute Theory of Polymers, D-01069 Dresden, Germany
| |
Collapse
|
10
|
Gong B, Wang L, Wang S, Yu Z, Xiong L, Xiong R, Liu Q, Zhang Y. Optimizing skyrmionium movement and stability via stray magnetic fields in trilayer nanowire constructs. Phys Chem Chem Phys 2024; 26:4716-4723. [PMID: 38251958 DOI: 10.1039/d3cp05340g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2024]
Abstract
Skyrmioniums, known for their unique transport and regulatory properties, are emerging as potential cornerstones for future data storage systems. However, the stability of skyrmionium movement faces considerable challenges due to the skyrmion Hall effect, which is induced by deformation. In response, our research introduces an innovative solution: we utilized micro-magnetic simulations to create a sandwiched trilayer nanowire structure augmented with a stray magnetic field. This combination effectively guides the skyrmionium within the ferromagnetic (FM) layer. Our empirical investigations reveal that the use of a stray magnetic field not only reduces the size of the skyrmionium but also amplifies its stability. This dual-effect proficiently mitigates the deformation of skyrmionium movement and boosts their thermal stability. We find these positive outcomes are most pronounced at a particular intensity of the stray magnetic field. Importantly, the required stray magnetic field can be generated using a heavy metal (HM1) layer of suitable thickness, rendering the practical application of this approach plausible in real-world experiments. Additionally, we analyze the functioning mechanism based on the Landau-Lifshitz-Gilbert (LLG) equation and energy variation. We also develop a deep spiking neural network (DSNN), which achieves a remarkable recognition accuracy of 97%. This achievement is realized through supervised learning via the spike timing dependent plasticity rule (STDP), considering the nanostructure as an artificial synapse device that corresponds to the electrical properties of the nanostructure. In conclusion, our study provides invaluable insights for the design of innovative information storage devices utilizing skyrmionium technology. By tackling the issues presented by the skyrmion Hall effect, we outline a feasible route for the practical application of this advanced technology. Our research, therefore, serves as a robust platform for continued investigations in this field.
Collapse
Affiliation(s)
- Bin Gong
- Hubei Key Laboratory of Optical Information and Pattern Recognition, School of Optical Information and Energy Engineering, Wuhan Institute of Technology, Wuhan 430205, P. R. China.
- Fujian Provincial Key Laboratory of Semiconductors and Applications, Collaborative Innovation Center for Optoelectronic Semiconductors and Efficient Devices, Department of Physics, Xiamen University, Xiamen 361005, P. R. China
| | - Luowen Wang
- Hubei Key Laboratory of Optical Information and Pattern Recognition, School of Optical Information and Energy Engineering, Wuhan Institute of Technology, Wuhan 430205, P. R. China.
| | - Sunan Wang
- Hubei Key Laboratory of Optical Information and Pattern Recognition, School of Optical Information and Energy Engineering, Wuhan Institute of Technology, Wuhan 430205, P. R. China.
| | - Ziyang Yu
- Hubei Key Laboratory of Optical Information and Pattern Recognition, School of Optical Information and Energy Engineering, Wuhan Institute of Technology, Wuhan 430205, P. R. China.
| | - Lun Xiong
- Hubei Key Laboratory of Optical Information and Pattern Recognition, School of Optical Information and Energy Engineering, Wuhan Institute of Technology, Wuhan 430205, P. R. China.
| | - Rui Xiong
- Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - Qingbo Liu
- Hubei Key Laboratory of Optical Information and Pattern Recognition, School of Optical Information and Energy Engineering, Wuhan Institute of Technology, Wuhan 430205, P. R. China.
| | - Yue Zhang
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
| |
Collapse
|
11
|
Raj RK, Bindal N, Kaushik BK. Skyrmion motion under temperature gradient and application in logic devices. NANOTECHNOLOGY 2023; 35:075703. [PMID: 38014695 DOI: 10.1088/1361-6528/acfd33] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Accepted: 09/25/2023] [Indexed: 11/29/2023]
Abstract
Under the presence of temperature gradient (TG) on a nanotrack, it is necessary to investigate the skyrmion dynamics in various magnetic systems under the combined effect of forces due to magnonic spin transfer torque(μSTT),thermal STT (τSTT), entropic difference(dS),as well as thermal induced dipolar field (DF). Hence, in this work, the dynamics of skyrmions in ferromagnets (FM), synthetic antiferromagnets (SAF), and antiferromagnets (AFM) have been studied under different TGs and damping constants (αG). It is observed thatαGplays a major role in deciding the direction of skyrmion motion either towards the hotter or colder side in different magnetic structures. Later, FM skyrmion based logic device is proposed that consists of a cross-coupled nanotrack, where the skyrmions on horizontal and vertical nanotrack are controlled by exploiting TG and electrical STT (eSTT), respectively by taking the advantages of thermal induced skyrmion Hall effect (SkHE). The proposed device performs AND and OR logic functionalities simultaneously, when the applied current density is2×1011Am-2.Moreover, the proposed device is also able to exhibit the half adder functionality by tuning the applied current density to3×1011Am-2.The total energy consumption for AND and OR logic operation and half adder are 33.63 fJ and 25.06 fJ, respectively. This paves the way for the development of energy-efficient logic devices with ultra-high storage density.
Collapse
Affiliation(s)
- Ravish Kumar Raj
- Department of Electronics and Communication Engineering, Indian Institute of Technology, Roorkee 247667, India
| | - Namita Bindal
- Department of Electronics and Communication Engineering, Indian Institute of Technology, Roorkee 247667, India
| | - Brajesh Kumar Kaushik
- Department of Electronics and Communication Engineering, Indian Institute of Technology, Roorkee 247667, India
| |
Collapse
|
12
|
Cho J, Jung J, Kim SB, Ju WR, Kim DH, Byun M, Kim JS. The Stack Optimization of Magnetic Heterojunction Structures for Next-Generation Spintronic Logic Applications. MATERIALS (BASEL, SWITZERLAND) 2023; 16:6418. [PMID: 37834555 PMCID: PMC10573172 DOI: 10.3390/ma16196418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 09/18/2023] [Accepted: 09/25/2023] [Indexed: 10/15/2023]
Abstract
Magnetic heterojunction structures with a suppressed interfacial Dzyaloshinskii-Moriya interaction and a sustainable long-range interlayer exchange coupling are achieved with an ultrathin platinum insertion layer. The systematic inelastic light scattering spectroscopy measurements indicate that the insertion layer restores the symmetry of the system and, then, the interfacial Dzyaloshinskii-Moriya interaction, which can prevent the identical magnetic domain wall motions, is obviously minimized. Nevertheless, the strong interlayer exchange coupling of the system is maintained. Consequently, synthetic ferromagnetic and antiferromagnetic exchange couplings as a function of the ruthenium layer thickness are observed as well. Therefore, these optimized magnetic multilayer stacks can avoid crucial issues, such as domain wall tilting and position problems, for next-generation spintronic logic applications. Moreover, the synthetic antiferromagnetic coupling can open a new path to develop a radically different NOT gate via current-induced magnetic domain wall motions and inversions.
Collapse
Affiliation(s)
- Jaehun Cho
- Division of Nanotechnology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Republic of Korea
| | - Jinyong Jung
- Department of Physics and Chemistry, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Republic of Korea
| | - Seong Bok Kim
- Division of Nanotechnology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Republic of Korea
| | - Woo Ri Ju
- Division of Nanotechnology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Republic of Korea
| | - Da Hyeon Kim
- Division of Nanotechnology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Republic of Korea
- Department of Materials Engineering, Keimyung University, Daegu 42601, Republic of Korea
| | - Myunghwan Byun
- Department of Materials Engineering, Keimyung University, Daegu 42601, Republic of Korea
| | - June-Seo Kim
- Division of Nanotechnology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Republic of Korea
| |
Collapse
|
13
|
Dohi T, Weißenhofer M, Kerber N, Kammerbauer F, Ge Y, Raab K, Zázvorka J, Syskaki MA, Shahee A, Ruhwedel M, Böttcher T, Pirro P, Jakob G, Nowak U, Kläui M. Enhanced thermally-activated skyrmion diffusion with tunable effective gyrotropic force. Nat Commun 2023; 14:5424. [PMID: 37696785 PMCID: PMC10495465 DOI: 10.1038/s41467-023-40720-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 08/07/2023] [Indexed: 09/13/2023] Open
Abstract
Magnetic skyrmions, topologically-stabilized spin textures that emerge in magnetic systems, have garnered considerable interest due to a variety of electromagnetic responses that are governed by the topology. The topology that creates a microscopic gyrotropic force also causes detrimental effects, such as the skyrmion Hall effect, which is a well-studied phenomenon highlighting the influence of topology on the deterministic dynamics and drift motion. Furthermore, the gyrotropic force is anticipated to have a substantial impact on stochastic diffusive motion; however, the predicted repercussions have yet to be demonstrated, even qualitatively. Here we demonstrate enhanced thermally-activated diffusive motion of skyrmions in a specifically designed synthetic antiferromagnet. Suppressing the effective gyrotropic force by tuning the angular momentum compensation leads to a more than 10 times enhanced diffusion coefficient compared to that of ferromagnetic skyrmions. Consequently, our findings not only demonstrate the gyro-force dependence of the diffusion coefficient but also enable ultimately energy-efficient unconventional stochastic computing.
Collapse
Affiliation(s)
- Takaaki Dohi
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 7, 55128, Mainz, Germany.
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Sendai, 980-8577, Japan.
| | - Markus Weißenhofer
- Fachbereich Physik, Universität Konstanz, DE-78457, Konstanz, Germany.
- Department of Physics and Astronomy, Uppsala University, P.O. Box 516, S-751 20, Uppsala, Sweden.
- Department of Physics, Freie Universität Berlin, Arnimallee 14, D-14195, Berlin, Germany.
| | - Nico Kerber
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 7, 55128, Mainz, Germany
- Graduate School of Excellence Materials Science in Mainz, Staudingerweg 9, 55128, Mainz, Germany
| | - Fabian Kammerbauer
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 7, 55128, Mainz, Germany
| | - Yuqing Ge
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 7, 55128, Mainz, Germany
| | - Klaus Raab
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 7, 55128, Mainz, Germany
| | - Jakub Zázvorka
- Institute of Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, Prague, 12116, Czech Republic
| | - Maria-Andromachi Syskaki
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 7, 55128, Mainz, Germany
- Singulus Technologies AG, 63796, Kahl am Main, Germany
| | - Aga Shahee
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 7, 55128, Mainz, Germany
| | - Moritz Ruhwedel
- Fachbereich Physik and Landesforschungszentrum OPTIMAS, Technische Universität Kaiserslautern, Gottlieb-Daimler-Straße 46, 67663, Kaiserslautern, Germany
| | - Tobias Böttcher
- Graduate School of Excellence Materials Science in Mainz, Staudingerweg 9, 55128, Mainz, Germany
- Fachbereich Physik and Landesforschungszentrum OPTIMAS, Technische Universität Kaiserslautern, Gottlieb-Daimler-Straße 46, 67663, Kaiserslautern, Germany
| | - Philipp Pirro
- Fachbereich Physik and Landesforschungszentrum OPTIMAS, Technische Universität Kaiserslautern, Gottlieb-Daimler-Straße 46, 67663, Kaiserslautern, Germany
| | - Gerhard Jakob
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 7, 55128, Mainz, Germany
- Graduate School of Excellence Materials Science in Mainz, Staudingerweg 9, 55128, Mainz, Germany
| | - Ulrich Nowak
- Fachbereich Physik, Universität Konstanz, DE-78457, Konstanz, Germany
| | - Mathias Kläui
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 7, 55128, Mainz, Germany.
- Graduate School of Excellence Materials Science in Mainz, Staudingerweg 9, 55128, Mainz, Germany.
| |
Collapse
|
14
|
Yagan R, Cheghabouri AM, Onbasli MC. Stabilization and adiabatic control of antiferromagnetically coupled skyrmions without the topological Hall effect. NANOSCALE ADVANCES 2023; 5:4470-4479. [PMID: 37638152 PMCID: PMC10448311 DOI: 10.1039/d3na00236e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Accepted: 07/26/2023] [Indexed: 08/29/2023]
Abstract
Synthetic antiferromagnetically coupled (SAF) multilayers provide different physics of stabilizing skyrmions while eliminating the topological Hall effect (THE), enabling efficient and stable control. The effects of material parameters, external current drive, and a magnetic field on the skyrmion equilibrium and propagation characteristics are largely unresolved. Here, we present a computational and theoretical demonstration of the large window of material parameters that stabilize SAF skyrmions determined by saturation magnetization, uniaxial anisotropy, and Dzyaloshinskii-Moriya interaction. Current-driven SAF skyrmion velocities reach ∼200 m s-1 without the THE. The SAF velocities are about 3-10 times greater than the typical ferromagnetic skyrmion velocities. The current densities needed for driving SAF skyrmions could be reduced to 108 A m-2, while 1011 A m-2 or above is needed for ferromagnetic skyrmions. By reducing the SAF skyrmion drive current by 3 orders, Joule heating is reduced by 6 orders of magnitude. These results pave the way for new SAF interfaces with improved equilibrium, dynamics, and power savings in THE-free skyrmionics.
Collapse
Affiliation(s)
- Rawana Yagan
- Department of Electrical and Electronics Engineering, Koç University Sarıyer Istanbul 34450 Turkey
| | | | - Mehmet C Onbasli
- Department of Electrical and Electronics Engineering, Koç University Sarıyer Istanbul 34450 Turkey
- Department of Physics, Koç University Sarıyer Istanbul 34450 Turkey
| |
Collapse
|
15
|
Tang N, Liyanage WLNC, Montoya SA, Patel S, Quigley LJ, Grutter AJ, Fitzsimmons MR, Sinha S, Borchers JA, Fullerton EE, DeBeer-Schmitt L, Gilbert DA. Skyrmion-Excited Spin-Wave Fractal Networks. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2300416. [PMID: 37139924 DOI: 10.1002/adma.202300416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 04/24/2023] [Indexed: 05/05/2023]
Abstract
Magnetic skyrmions exhibit unique, technologically relevant pseudo-particle behaviors which arise from their topological protection, including well-defined, 3D dynamic modes that occur at microwave frequencies. During dynamic excitation, spin waves are ejected into the interstitial regions between skyrmions, creating the magnetic equivalent of a turbulent sea. However, since the spin waves in these systems have a well-defined length scale, and the skyrmions are on an ordered lattice, ordered structures from spin-wave interference can precipitate from the chaos. This work uses small-angle neutron scattering (SANS) to capture the dynamics in hybrid skyrmions and investigate the spin-wave structure. Performing simultaneous ferromagnetic resonance and SANS, the diffraction pattern shows a large increase in low-angle scattering intensity, which is present only in the resonance condition. This scattering pattern is best fit using a mass fractal model, which suggests the spin waves form a long-range fractal network. The fractal structure is constructed of fundamental units with a size that encodes the spin-wave emissions and are constrained by the skyrmion lattice. These results offer critical insights into the nanoscale dynamics of skyrmions, identify a new dynamic spin-wave fractal structure, and demonstrate SANS as a unique tool to probe high-speed dynamics.
Collapse
Affiliation(s)
- Nan Tang
- Materials Science and Engineering Department, University of Tennessee, Knoxville, TN, 37996, USA
| | - W L N C Liyanage
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN, 37996, USA
| | - Sergio A Montoya
- Center for Memory and Recording Research, University of California, San Diego, La Jolla, CA, 92093, USA
- Naval Information Warfare Center Pacific, San Diego, CA, 92152, USA
| | - Sheena Patel
- Center for Memory and Recording Research, University of California, San Diego, La Jolla, CA, 92093, USA
- Physics Department, University of California, San Diego, San Diego, CA, 92093, USA
| | - Lizabeth J Quigley
- Materials Science and Engineering Department, University of Tennessee, Knoxville, TN, 37996, USA
| | - Alexander J Grutter
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | - Michael R Fitzsimmons
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN, 37996, USA
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Sunil Sinha
- Physics Department, University of California, San Diego, San Diego, CA, 92093, USA
| | - Julie A Borchers
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | - Eric E Fullerton
- Center for Memory and Recording Research, University of California, San Diego, La Jolla, CA, 92093, USA
- Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Lisa DeBeer-Schmitt
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Dustin A Gilbert
- Materials Science and Engineering Department, University of Tennessee, Knoxville, TN, 37996, USA
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN, 37996, USA
| |
Collapse
|
16
|
Meisenheimer P, Zhang H, Raftrey D, Chen X, Shao YT, Chan YT, Yalisove R, Chen R, Yao J, Scott MC, Wu W, Muller DA, Fischer P, Birgeneau RJ, Ramesh R. Ordering of room-temperature magnetic skyrmions in a polar van der Waals magnet. Nat Commun 2023; 14:3744. [PMID: 37353526 DOI: 10.1038/s41467-023-39442-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 06/13/2023] [Indexed: 06/25/2023] Open
Abstract
Control and understanding of ensembles of skyrmions is important for realization of future technologies. In particular, the order-disorder transition associated with the 2D lattice of magnetic skyrmions can have significant implications for transport and other dynamic functionalities. To date, skyrmion ensembles have been primarily studied in bulk crystals, or as isolated skyrmions in thin film devices. Here, we investigate the condensation of the skyrmion phase at room temperature and zero field in a polar, van der Waals magnet. We demonstrate that we can engineer an ordered skyrmion crystal through structural confinement on the μm scale, showing control over this order-disorder transition on scales relevant for device applications.
Collapse
Affiliation(s)
- Peter Meisenheimer
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA.
| | - Hongrui Zhang
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA.
| | - David Raftrey
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Physics, University of California, Santa Cruz, CA, USA
| | - Xiang Chen
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Physics, University of California, Berkeley, CA, USA
| | - Yu-Tsun Shao
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA
| | - Ying-Ting Chan
- Department of Physics, Rutgers University, New Brunswick, NJ, USA
| | - Reed Yalisove
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | - Rui Chen
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | - Jie Yao
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | - Mary C Scott
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Weida Wu
- Department of Physics, Rutgers University, New Brunswick, NJ, USA
| | - David A Muller
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA
| | - Peter Fischer
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Physics, University of California, Santa Cruz, CA, USA
| | - Robert J Birgeneau
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Physics, University of California, Berkeley, CA, USA
| | - Ramamoorthy Ramesh
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Physics, University of California, Berkeley, CA, USA
| |
Collapse
|
17
|
Schöpf J, Thampi A, Milde P, Ivaneyko D, Kondovych S, Kononenko DY, Eng LM, Jin L, Yang L, Wysocki L, van Loosdrecht PHM, Richter K, Yershov KV, Wolf D, Lubk A, Lindfors-Vrejoiu I. Néel Skyrmion Bubbles in La 0.7Sr 0.3Mn 1-xRu xO 3 Multilayers. NANO LETTERS 2023; 23:3532-3539. [PMID: 37018631 DOI: 10.1021/acs.nanolett.3c00693] [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
Ferromagnetic La0.7Sr0.3Mn1-xRuxO3 epitaxial multilayers with controlled variation of the Ru/Mn content were synthesized to engineer canted magnetic anisotropy and variable exchange interactions, and to explore the possibility of generating a Dzyaloshinskii-Moriya interaction. The ultimate aim of the multilayer design is to provide the conditions for the formation of domains with nontrivial magnetic topology in an oxide thin film system. Employing magnetic force microscopy and Lorentz transmission electron microscopy in varying perpendicular magnetic fields, magnetic stripe domains separated by Néel-type domain walls as well as Néel skyrmions smaller than 100 nm in diameter were observed. These findings are consistent with micromagnetic modeling, taking into account a sizable Dzyaloshinskii-Moriya interaction arising from the inversion symmetry breaking and possibly from strain effects in the multilayer system.
Collapse
Affiliation(s)
- Jörg Schöpf
- II. Physics Institute, University of Cologne, 50937 Cologne, Germany
| | - Arsha Thampi
- Institute for Solid State Research, IFW Dresden, 01069 Dresden, Germany
| | - Peter Milde
- Institute of Applied Physics, TU Dresden, 01062 Dresden, Germany
| | - Dmytro Ivaneyko
- Institute of Applied Physics, TU Dresden, 01062 Dresden, Germany
| | - Svitlana Kondovych
- Institute for Theoretical Solid State Physics, IFW Dresden, 01069 Dresden, Germany
| | - Denys Y Kononenko
- Institute for Theoretical Solid State Physics, IFW Dresden, 01069 Dresden, Germany
| | - Lukas M Eng
- Institute of Applied Physics, TU Dresden, 01062 Dresden, Germany
- ct.qmat, Dresden-Würzburg Cluster of Excellence-EXC 2147, TU Dresden, 01062 Dresden, Germany
| | - Lei Jin
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Lin Yang
- II. Physics Institute, University of Cologne, 50937 Cologne, Germany
| | - Lena Wysocki
- II. Physics Institute, University of Cologne, 50937 Cologne, Germany
| | | | - Kornel Richter
- Faculty of Sciences, Pavol Jozef Safarik University, Park Angelinum 9, 041 54 Kosice, Slovakia
| | - Kostiantyn V Yershov
- Institute for Theoretical Solid State Physics, IFW Dresden, 01069 Dresden, Germany
- Bogolyubov Institute for Theoretical Physics of the National Academy of Sciences of Ukraine, 03143 Kyiv, Ukraine
| | - Daniel Wolf
- Institute for Solid State Research, IFW Dresden, 01069 Dresden, Germany
| | - Axel Lubk
- Institute for Solid State Research, IFW Dresden, 01069 Dresden, Germany
- Institute of Solid State and Materials Physics, TU Dresden, 01062 Dresden, Germany
| | | |
Collapse
|
18
|
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.
Collapse
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
| |
Collapse
|
19
|
Lancaster S, Arnay I, Guerrero R, Gudín A, Guedeja-Marrón A, Diez JM, Gärtner J, Anadón A, Varela M, Camarero J, Mikolajick T, Perna P, Slesazeck S. Toward Nonvolatile Spin-Orbit Devices: Deposition of Ferroelectric Hafnia on Monolayer Graphene/Co/HM Stacks. ACS APPLIED MATERIALS & INTERFACES 2023; 15:16963-16974. [PMID: 36951382 DOI: 10.1021/acsami.2c22205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
While technologically challenging, the integration of ferroelectric thin films with graphene spintronics potentially allows the realization of highly efficient, electrically tunable, nonvolatile memories through control of the interfacial spin-orbit driven interaction occurring at graphene/Co interfaces deposited on heavy metal supports. Here, the integration of ferroelectric Hf0.5Zr0.5O2 on graphene/Co/heavy metal epitaxial stacks is investigated via the implementation of several nucleation methods in atomic layer deposition. By employing in situ Al2O3 as a nucleation layer sandwiched between Hf0.5Zr0.5O2 and graphene, the Hf0.5Zr0.5O2 demonstrates a remanent polarization (2Pr) of 19.2 μC/cm2. Using an ex situ, naturally oxidized sputtered Ta layer for nucleation, we could control 2Pr via the interlayer thickness, reaching maximum values of 28 μC/cm2 with low coercive fields. Magnetic hysteresis measurements taken before and after atomic layer deposition show strong perpendicular magnetic anisotropy, with minimal deviations in the magnetization reversal pathways due to the Hf0.5Zr0.5O2 deposition process, thus pointing to a good preservation of the magnetic stack including single-layer graphene. X-ray diffraction measurements further confirm that the high-quality interfaces demonstrated in the stack remain unperturbed by the ferroelectric deposition and anneal. The proposed graphene-based ferroelectric/magnetic structures offer the strong advantages of ferroelectricity and ferromagnetism at room temperature, enabling the development of novel magneto-electric and nonvolatile in-memory spin-orbit logic architectures with low power switching.
Collapse
Affiliation(s)
| | - Iciar Arnay
- IMDEA Nanociencia, c/Faraday 9, Madrid 28049, Spain
| | | | - Adrian Gudín
- IMDEA Nanociencia, c/Faraday 9, Madrid 28049, Spain
| | - Alejandra Guedeja-Marrón
- Departamento de Física de Materiales and Instituto Pluridisciplinar, Universidad Complutense de Madrid, Ciudad Universitaria, Madrid 28040, Spain
| | - Jose Manuel Diez
- Departamento de Física de la Materia Condensada & Departamento de Física Aplicada & Instituto Nicolás Cabrera, Universidad Autónoma de Madrid, Madrid 28049, Spain
| | - Jan Gärtner
- NaMLab gGmbH, Nöthnitzer Strasse 64a, Dresden 01187, Germany
| | | | - Maria Varela
- Departamento de Física de Materiales and Instituto Pluridisciplinar, Universidad Complutense de Madrid, Ciudad Universitaria, Madrid 28040, Spain
| | - Julio Camarero
- Departamento de Física de la Materia Condensada & Departamento de Física Aplicada & Instituto Nicolás Cabrera, Universidad Autónoma de Madrid, Madrid 28049, Spain
| | - Thomas Mikolajick
- NaMLab gGmbH, Nöthnitzer Strasse 64a, Dresden 01187, Germany
- Institute of Semiconductors and Microsystems, Technische Universität Dresden, Nöthnitzer Strasse 64, Dresden 01187, Germany
| | - Paolo Perna
- IMDEA Nanociencia, c/Faraday 9, Madrid 28049, Spain
| | | |
Collapse
|
20
|
Paul N, Zhang Y, Fu L. Giant proximity exchange and flat Chern band in 2D magnet-semiconductor heterostructures. SCIENCE ADVANCES 2023; 9:eabn1401. [PMID: 36827369 DOI: 10.1126/sciadv.abn1401] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 01/24/2023] [Indexed: 06/18/2023]
Abstract
van der Waals (vdW) heterostructures formed by two-dimensional (2D) magnets and semiconductors have provided a fertile ground for fundamental science and spintronics. We present first-principles calculations finding a proximity exchange splitting of 14 meV (equivalent to an effective Zeeman field of 120 T) in the vdW magnet-semiconductor heterostructure MoS 2/CrBr 3, leading to a 2D spin-polarized half-metal with carrier densities ranging up to 1013 cm-2. We consequently explore the effect of large exchange coupling on the electronic band structure when the magnetic layer hosts chiral spin textures such as skyrmions. A flat Chern band is found at a "magic" value of magnetization [Formula: see text] for Schrödinger electrons, and it generally occurs for Dirac electrons. The magnetic proximity-induced anomalous Hall effect enables transport-based detection of chiral spin textures, and flat Chern bands provide an avenue for engineering various strongly correlated states.
Collapse
Affiliation(s)
- Nisarga Paul
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Yang Zhang
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Liang Fu
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| |
Collapse
|
21
|
Dai B, Wu D, Razavi SA, Xu S, He H, Shu Q, Jackson M, Mahfouzi F, Huang H, Pan Q, Cheng Y, Qu T, Wang T, Tai L, Wong K, Kioussis N, Wang KL. Electric field manipulation of spin chirality and skyrmion dynamic. SCIENCE ADVANCES 2023; 9:eade6836. [PMID: 36791189 PMCID: PMC9931210 DOI: 10.1126/sciadv.ade6836] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 01/12/2023] [Indexed: 06/18/2023]
Abstract
The Dzyaloshinskii-Moriya interaction (DMI) is an antisymmetric exchange interaction that stabilizes spin chirality. One scientific and technological challenge is understanding and controlling the interaction between spin chirality and electric field. In this study, we investigate an unconventional electric field effect on interfacial DMI, skyrmion helicity, and skyrmion dynamics in a system with broken inversion symmetry. We design heterostructures with a 3d-5d atomic orbital interface to demonstrate the gate bias control of the DMI energy and thus transform the DMI between opposite chiralities. Furthermore, we use this voltage-controlled DMI (VCDMI) to manipulate the skyrmion spin texture. As a result, a type of intermediate skyrmion with a unique helicity is created, and its motion can be controlled and made to go straight. Our work shows the effective control of spin chirality, skyrmion helicity, and skyrmion dynamics by VCDMI. It promotes the emerging field of voltage-controlled chiral interactions and voltage-controlled skyrmionics.
Collapse
Affiliation(s)
- Bingqian Dai
- Departments of Electrical and Computer Engineering, Physics and Astronomy, and Material Science and Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Di Wu
- Departments of Electrical and Computer Engineering, Physics and Astronomy, and Material Science and Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Seyed Armin Razavi
- Departments of Electrical and Computer Engineering, Physics and Astronomy, and Material Science and Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Shijie Xu
- Departments of Electrical and Computer Engineering, Physics and Astronomy, and Material Science and Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Haoran He
- Departments of Electrical and Computer Engineering, Physics and Astronomy, and Material Science and Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Qingyuan Shu
- Departments of Electrical and Computer Engineering, Physics and Astronomy, and Material Science and Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Malcolm Jackson
- Departments of Electrical and Computer Engineering, Physics and Astronomy, and Material Science and Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Farzad Mahfouzi
- Department of Physics and Astronomy, California State University, Northridge, Los Angeles, CA 91330-8268, USA
| | - Hanshen Huang
- Departments of Electrical and Computer Engineering, Physics and Astronomy, and Material Science and Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Quanjun Pan
- Departments of Electrical and Computer Engineering, Physics and Astronomy, and Material Science and Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Yang Cheng
- Departments of Electrical and Computer Engineering, Physics and Astronomy, and Material Science and Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Tao Qu
- Departments of Electrical and Computer Engineering, Physics and Astronomy, and Material Science and Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Tianyi Wang
- Departments of Electrical and Computer Engineering, Physics and Astronomy, and Material Science and Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Lixuan Tai
- Departments of Electrical and Computer Engineering, Physics and Astronomy, and Material Science and Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Kin Wong
- Departments of Electrical and Computer Engineering, Physics and Astronomy, and Material Science and Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Nicholas Kioussis
- Department of Physics and Astronomy, California State University, Northridge, Los Angeles, CA 91330-8268, USA
| | - Kang L. Wang
- Departments of Electrical and Computer Engineering, Physics and Astronomy, and Material Science and Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| |
Collapse
|
22
|
Sivasubramani S, Paikaray B, Kuchibhotla M, Haldar A, Murapaka C, Acharyya A. Skyrmion based 3D low complex runtime reconfigurable architecture design methodology of universal logic gate. NANOTECHNOLOGY 2023; 34:13LT01. [PMID: 36584387 DOI: 10.1088/1361-6528/acaf32] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 12/29/2022] [Indexed: 06/17/2023]
Abstract
In this study, we introduce the area efficient low complex runtime reconfigurable architecture design methodology based on Skyrmion logic for universal logic gate (ULG) i.e. NOR/NAND implementation using micromagnetic simulations. We have modelled the two input 3D device structure using bilayer ferromagnet/heavy metal where the magnetic tunnel junctions inject and detect the input and output skyrmions by exploiting the input reversal mechanism. The implementation of NOR and NAND is performed using this same device where it is reconfigured runtime with enhanced tunability by the ON and OFF state of current passing through a non magnetic metallic gate respectively. This gate acts as a barrier for skyrmion motion (additional control mechanism) to realize the required Skyrmion logic output states. To the best of authors's knowledge the boolean optimizations and the mapping logic have been presented for the first time to demonstrate the functionalities of the NOR/NAND implementation. This proposed architecture design methodology of ULG leads to reduced device footprint with regard to the number of thin film structures proposed, low complexity in terms of fabrication and also providing runtime reconfigurability to reduce the number of physical designs to achieve all truth table entries (∼75% device footprint reduction). The proposed 3D ULG architecture design benefits from the miniaturization resulting in opening up a new perspective for magneto-logic devices.
Collapse
Affiliation(s)
- Santhosh Sivasubramani
- Advanced Embedded Systems and IC Design Laboratory, Department of Electrical Engineering, Indian Institute of Technology (IIT) Hyderabad, 502284, India
| | - Bibekananda Paikaray
- Department of Materials Science and Metallurgical Engineering, Indian Institute of Technology (IIT) Hyderabad, 502284, India
| | - Mahathi Kuchibhotla
- Department of Physics, Indian Institute of Technology (IIT) Hyderabad, 502284, India
| | - Arabinda Haldar
- Department of Physics, Indian Institute of Technology (IIT) Hyderabad, 502284, India
| | - Chandrasekhar Murapaka
- Department of Materials Science and Metallurgical Engineering, Indian Institute of Technology (IIT) Hyderabad, 502284, India
| | - Amit Acharyya
- Advanced Embedded Systems and IC Design Laboratory, Department of Electrical Engineering, Indian Institute of Technology (IIT) Hyderabad, 502284, India
| |
Collapse
|
23
|
Powalla L, Birch MT, Litzius K, Wintz S, Schulz F, Weigand M, Scholz T, Lotsch BV, Kern K, Schütz G, Burghard M. Single Skyrmion Generation via a Vertical Nanocontact in a 2D Magnet-Based Heterostructure. NANO LETTERS 2022; 22:9236-9243. [PMID: 36400013 PMCID: PMC9756335 DOI: 10.1021/acs.nanolett.2c01944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 11/07/2022] [Indexed: 06/16/2023]
Abstract
Skyrmions have been well studied in chiral magnets and magnetic thin films due to their potential application in practical devices. Recently, monochiral skyrmions have been observed in two-dimensional van der Waals magnets. Their atomically flat surfaces and capability to be stacked into heterostructures offer new prospects for skyrmion applications. However, the controlled local nucleation of skyrmions within these materials has yet to be realized. Here, we utilize real-space X-ray microscopy to investigate a heterostructure composed of the 2D ferromagnet Fe3GeTe2 (FGT), an insulating hexagonal boron nitride layer, and a graphite top electrode. Upon a stepwise increase of the voltage applied between the graphite and FGT, a vertically conducting pathway can be formed. This nanocontact allows the tunable creation of individual skyrmions via single nanosecond pulses of low current density. Furthermore, time-resolved magnetic imaging highlights the stability of the nanocontact, while our micromagnetic simulations reproduce the observed skyrmion nucleation process.
Collapse
Affiliation(s)
- Lukas Powalla
- Max
Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569Stuttgart, Germany
| | - Max T. Birch
- Max
Planck Institute for Intelligent Systems, Heisenbergstrasse 3, D-70569Stuttgart, Germany
| | - Kai Litzius
- Max
Planck Institute for Intelligent Systems, Heisenbergstrasse 3, D-70569Stuttgart, Germany
| | - Sebastian Wintz
- Max
Planck Institute for Intelligent Systems, Heisenbergstrasse 3, D-70569Stuttgart, Germany
- Helmholtz-Zentrum
Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109Berlin, Germany
| | - Frank Schulz
- Max
Planck Institute for Intelligent Systems, Heisenbergstrasse 3, D-70569Stuttgart, Germany
| | - Markus Weigand
- Max
Planck Institute for Intelligent Systems, Heisenbergstrasse 3, D-70569Stuttgart, Germany
- Helmholtz-Zentrum
Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109Berlin, Germany
| | - Tanja Scholz
- Max
Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569Stuttgart, Germany
| | - Bettina V. Lotsch
- Max
Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569Stuttgart, Germany
- University
of Munich (LMU), Butenandtstraße 5-13 (Haus D), 81377München, Germany
| | - Klaus Kern
- Max
Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569Stuttgart, Germany
- Institute
de Physique, École Polytechnique
Fédérale de Lausanne, CH-1015Lausanne, Switzerland
| | - Gisela Schütz
- Max
Planck Institute for Intelligent Systems, Heisenbergstrasse 3, D-70569Stuttgart, Germany
| | - Marko Burghard
- Max
Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569Stuttgart, Germany
| |
Collapse
|
24
|
Aldarawsheh A, Fernandes IL, Brinker S, Sallermann M, Abusaa M, Blügel S, Lounis S. Emergence of zero-field non-synthetic single and interchained antiferromagnetic skyrmions in thin films. Nat Commun 2022; 13:7369. [DOI: 10.1038/s41467-022-35102-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 11/15/2022] [Indexed: 12/02/2022] Open
Abstract
AbstractAntiferromagnetic (AFM) skyrmions are envisioned as ideal localized topological magnetic bits in future information technologies. In contrast to ferromagnetic (FM) skyrmions, they are immune to the skyrmion Hall effect, might offer potential terahertz dynamics while being insensitive to external magnetic fields and dipolar interactions. Although observed in synthetic AFM structures and as complex meronic textures in intrinsic AFM bulk materials, their realization in non-synthetic AFM films, of crucial importance in racetrack concepts, has been elusive. Here, we unveil their presence in a row-wise AFM Cr film deposited on PdFe bilayer grown on fcc Ir(111) surface. Using first principles, we demonstrate the emergence of single and strikingly interpenetrating chains of AFM skyrmions, which can co-exist with the rich inhomogeneous exchange field, including that of FM skyrmions, hosted by PdFe. Besides the identification of an ideal platform of materials for intrinsic AFM skyrmions, we anticipate the uncovered knotted solitons to be promising building blocks in AFM spintronics.
Collapse
|
25
|
Criado JC, Schenk S, Spannowsky M, Hatton PD, Turnbull LA. Simulating anti-skyrmions on a lattice. Sci Rep 2022; 12:19179. [DOI: 10.1038/s41598-022-22043-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 10/07/2022] [Indexed: 11/11/2022] Open
Abstract
AbstractMagnetic skyrmions are meta-stable spin structures that naturally emerge in magnetic materials. While a vast amount of effort has gone into the study of their properties, their counterpart of opposite topological charge, the anti-skyrmion, has not received as much attention. We aim to close this gap by deploying Monte Carlo simulations of spin-lattice systems in order to investigate which interactions support anti-skyrmions, as well as skyrmions of Bloch and Néel type. We find that the combination of ferromagnetic exchange and Dzyaloshinskii–Moriya (DM) interactions is able to stabilize each of the three types, depending on the specific structure of the DM interactions. Considering a three-dimensional spin lattice model, we provide a finite-temperature phase diagram featuring a stable anti-skyrmion lattice phase for a large range of temperatures. In addition, we also shed light on the creation and annihilation processes of these anti-skyrmion tubes and study the effects of the DM interaction strength on their typical size.
Collapse
|
26
|
Yang S, Ju TS, Kim C, Kim HJ, An K, Moon KW, Park S, Hwang C. Magnetic Field Magnitudes Needed for Skyrmion Generation in a General Perpendicularly Magnetized Film. NANO LETTERS 2022; 22:8430-8436. [PMID: 36282733 PMCID: PMC9650724 DOI: 10.1021/acs.nanolett.2c02268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 10/08/2022] [Indexed: 06/16/2023]
Abstract
Due to its topological protection, the magnetic skyrmion has been intensively studied for both fundamental aspects and spintronics applications. However, despite recent advancements in skyrmion research, the deterministic creation of isolated skyrmions in a generic perpendicularly magnetized film is still one of the most essential and challenging techniques. Here, we present a method to create magnetic skyrmions in typical perpendicular magnetic anisotropy (PMA) films by applying a magnetic field pulse and a method to determine the magnitude of the required external magnetic fields. Furthermore, to demonstrate the usefulness of this result for future skyrmion research, we also experimentally study the PMA dependence on the minimum size of skyrmions. Although field-driven skyrmion generation is unsuitable for device application, this result can provide an easier approach for obtaining isolated skyrmions, making skyrmion-based research more accessible.
Collapse
Affiliation(s)
- Seungmo Yang
- Quantum
Spin Team, Korea Research Institute of Standards
and Science, Daejeon34113, Republic of Korea
| | - Tae-Seong Ju
- Quantum
Spin Team, Korea Research Institute of Standards
and Science, Daejeon34113, Republic of Korea
- Department
of Physics, Pusan National University, Busan46241, Republic of Korea
| | - Changsoo Kim
- Quantum
Spin Team, Korea Research Institute of Standards
and Science, Daejeon34113, Republic of Korea
| | - Hyun-Joong Kim
- Quantum
Spin Team, Korea Research Institute of Standards
and Science, Daejeon34113, Republic of Korea
| | - Kyongmo An
- Quantum
Spin Team, Korea Research Institute of Standards
and Science, Daejeon34113, Republic of Korea
| | - Kyoung-Woong Moon
- Quantum
Spin Team, Korea Research Institute of Standards
and Science, Daejeon34113, Republic of Korea
| | - Sungkyun Park
- Department
of Physics, Pusan National University, Busan46241, Republic of Korea
| | - Chanyong Hwang
- Quantum
Spin Team, Korea Research Institute of Standards
and Science, Daejeon34113, Republic of Korea
| |
Collapse
|
27
|
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.
Collapse
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
| |
Collapse
|
28
|
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: 14] [Impact Index Per Article: 7.0] [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.
Collapse
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.
| |
Collapse
|
29
|
Quessab Y, Xu JW, Cogulu E, Finizio S, Raabe J, Kent AD. Zero-Field Nucleation and Fast Motion of Skyrmions Induced by Nanosecond Current Pulses in a Ferrimagnetic Thin Film. NANO LETTERS 2022; 22:6091-6097. [PMID: 35877983 DOI: 10.1021/acs.nanolett.2c01038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Skyrmion racetrack memories are highly attractive for next-generation data storage technologies. Skyrmions are noncollinear spin textures stabilized by chiral interactions. To achieve a fast-operating memory device, it is critical to move skyrmions at high speeds. The skyrmion dynamics induced by spin-orbit torques (SOTs) in the commonly studied ferromagnetic films is hindered by strong pinning effects and a large skyrmion Hall effect causing deflection of the skyrmion toward the racetrack edge, which can lead to information loss. Here, we investigate the current-induced nucleation and motion of skyrmions in ferrimagnetic Pt/CoGd/(W or Ta) thin films. We first reveal field-free skyrmion nucleation mediated by Joule heating. We then achieve fast skyrmion motion driven by SOTs with velocities as high as 610 m s-1 and a small skyrmion Hall angle |θSkHE| ≲ 3°. Our results show that ferrimagnets are better candidates for fast skyrmion-based memory devices with low risk of information loss.
Collapse
Affiliation(s)
- Yassine Quessab
- Center for Quantum Phenomena, Department of Physics, New York University, New York, New York, 10003, United States
| | - Jun-Wen Xu
- Center for Quantum Phenomena, Department of Physics, New York University, New York, New York, 10003, United States
| | - Egecan Cogulu
- Center for Quantum Phenomena, Department of Physics, New York University, New York, New York, 10003, United States
| | - Simone Finizio
- Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Jörg Raabe
- Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Andrew D Kent
- Center for Quantum Phenomena, Department of Physics, New York University, New York, New York, 10003, United States
| |
Collapse
|
30
|
Vélez S, Ruiz-Gómez S, Schaab J, Gradauskaite E, Wörnle MS, Welter P, Jacot BJ, Degen CL, Trassin M, Fiebig M, Gambardella P. Current-driven dynamics and ratchet effect of skyrmion bubbles in a ferrimagnetic insulator. NATURE NANOTECHNOLOGY 2022; 17:834-841. [PMID: 35788187 DOI: 10.1038/s41565-022-01144-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 05/02/2022] [Indexed: 06/15/2023]
Abstract
Magnetic skyrmions are compact chiral spin textures that exhibit a rich variety of topological phenomena and hold potential for the development of high-density memory devices and novel computing schemes driven by spin currents. Here, we demonstrate the room-temperature interfacial stabilization and current-driven control of skyrmion bubbles in the ferrimagnetic insulator Tm3Fe5O12 coupled to Pt, showing the current-induced motion of individual skyrmion bubbles. The ferrimagnetic order of the crystal together with the interplay of spin-orbit torques and pinning determine the skyrmion dynamics in Tm3Fe5O12 and result in a strong skyrmion Hall effect characterized by a negative deflection angle and hopping motion. Further, we show that the velocity and depinning threshold of the skyrmion bubbles can be modified by exchange coupling Tm3Fe5O12 to an in-plane magnetized Y3Fe5O12 layer, which distorts the spin texture of the skyrmions and leads to directional-dependent rectification of their dynamics. This effect, which is equivalent to a magnetic ratchet, is exploited to control the skyrmion flow in a racetrack-like device.
Collapse
Affiliation(s)
- Saül Vélez
- Department of Materials, ETH Zurich, Zurich, Switzerland.
- Condensed Matter Physics Center, Instituto Nicolás Cabrera, and Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Madrid, Spain.
| | - Sandra Ruiz-Gómez
- Departamento de Física de Materiales, Universidad Complutense de Madrid, Madrid, Spain
- Alba Synchrotron Light Facility, Barcelona, Spain
- Max Planck Institute for Chemical Physics of Solids, Dresden, Germany
| | - Jakob Schaab
- Department of Materials, ETH Zurich, Zurich, Switzerland
| | | | | | - Pol Welter
- Department of Physics, ETH Zurich, Zurich, Switzerland
| | | | | | - Morgan Trassin
- Department of Materials, ETH Zurich, Zurich, Switzerland
| | - Manfred Fiebig
- Department of Materials, ETH Zurich, Zurich, Switzerland
| | | |
Collapse
|
31
|
Chen R, Li Y. Voltage-Controlled Skyrmionic Interconnect with Multiple Magnetic Information Carriers. ACS APPLIED MATERIALS & INTERFACES 2022; 14:30420-30434. [PMID: 35758014 PMCID: PMC9301624 DOI: 10.1021/acsami.2c07470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Magnetic skyrmions have been in the spotlight since they were observed in technologically relevant systems at room temperature. More recently, there has been increasing interest in additional quasiparticles that may exist as stable/metastable spin textures in magnets, such as the skyrmionium and the antiskyrmionite (i.e., a skyrmion bag with two skyrmions inside) that have distinct topological characteristics. The next challenge and opportunity, at the same time, is to investigate the use of multiple magnetic quasiparticles as information carriers in a single device for next-generation nanocomputing. In this paper, we propose a spintronic interconnect device where multiple sequences of information signals are encoded and transmitted simultaneously by skyrmions, skyrmioniums, and antiskyrmionites. The proposed spintronic interconnect device can be pipelined via voltage-controlled magnetic anisotropy (VCMA) gated synchronizers that behave as intermediate registers. We demonstrate theoretically that the interconnect throughput and transmission energy can be effectively tuned by the VCMA gate voltage and appropriate electric current pulses. By carefully adjusting the device structure characteristics, our spintronic interconnect device exhibits comparable energy efficiency with copper interconnects in mainstream CMOS technologies. This study provides fresh insight into the possibilities of skyrmionic devices in future spintronic applications.
Collapse
Affiliation(s)
- Runze Chen
- Department
of Computer Science, School of Engineering, The University of Manchester, Manchester M13 9PL, United Kingdom
| | - Yu Li
- Department
of Computer Science, School of Engineering, The University of Manchester, Manchester M13 9PL, United Kingdom
- Frontier
Institute of Chip and System, Fudan University, Shanghai 200433, China
| |
Collapse
|
32
|
MacKinnon CR, Zeissler K, Finizio S, Raabe J, Marrows CH, Mercer T, Bissell PR, Lepadatu S. Collective skyrmion motion under the influence of an additional interfacial spin-transfer torque. Sci Rep 2022; 12:10786. [PMID: 35750744 PMCID: PMC9232533 DOI: 10.1038/s41598-022-14969-2] [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: 02/15/2022] [Accepted: 06/15/2022] [Indexed: 11/26/2022] Open
Abstract
Here we study the effect of an additional interfacial spin-transfer torque, as well as the well-established spin–orbit torque and bulk spin-transfer torque, on skyrmion collections—group of skyrmions dense enough that they are not isolated from one another—in ultrathin heavy metal/ferromagnetic multilayers, by comparing modelling with experimental results. Using a skyrmion collection with a range of skyrmion diameters and landscape disorder, we study the dependence of the skyrmion Hall angle on diameter and velocity, as well as the velocity as a function of diameter. We show that inclusion of the interfacial spin-transfer torque results in reduced skyrmion Hall angles, with values close to experimental results. We also show that for skyrmion collections the velocity is approximately independent of diameter, in marked contrast to the motion of isolated skyrmions, as the group of skyrmions move together at an average group velocity. Moreover, the calculated skyrmion velocities are comparable to those obtained in experiments when the interfacial spin-transfer torque is included. Our results thus show the significance of the interfacial spin-transfer torque in ultrathin magnetic multilayers, which helps to explain the low skyrmion Hall angles and velocities observed in experiment. We conclude that the interfacial spin-transfer torque should be considered in numerical modelling for reproduction of experimental results.
Collapse
Affiliation(s)
- Callum R MacKinnon
- Jeremiah Horrocks Institute for Mathematics, Physics and Astronomy, University of Central Lancashire, Preston, PR1 2HE, UK.
| | - Katharina Zeissler
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK.,Bragg Center for Materials Research, University of Leeds, Leeds, LS2 9JT, UK
| | - Simone Finizio
- Swiss Light Source, Paul Scherrer Institut, 5232, Villigen, Switzerland
| | - Jörg Raabe
- Swiss Light Source, Paul Scherrer Institut, 5232, Villigen, Switzerland
| | - Christopher H Marrows
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK.,Bragg Center for Materials Research, University of Leeds, Leeds, LS2 9JT, UK
| | - Tim Mercer
- Jeremiah Horrocks Institute for Mathematics, Physics and Astronomy, University of Central Lancashire, Preston, PR1 2HE, UK
| | - Philip R Bissell
- Jeremiah Horrocks Institute for Mathematics, Physics and Astronomy, University of Central Lancashire, Preston, PR1 2HE, UK
| | - Serban Lepadatu
- Jeremiah Horrocks Institute for Mathematics, Physics and Astronomy, University of Central Lancashire, Preston, PR1 2HE, UK.
| |
Collapse
|
33
|
Birch MT, Powalla L, Wintz S, Hovorka O, Litzius K, Loudon JC, Turnbull LA, Nehruji V, Son K, Bubeck C, Rauch TG, Weigand M, Goering E, Burghard M, Schütz G. History-dependent domain and skyrmion formation in 2D van der Waals magnet Fe 3GeTe 2. Nat Commun 2022; 13:3035. [PMID: 35641499 PMCID: PMC9156682 DOI: 10.1038/s41467-022-30740-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 05/16/2022] [Indexed: 11/16/2022] Open
Abstract
The discovery of two-dimensional magnets has initiated a new field of research, exploring both fundamental low-dimensional magnetism, and prospective spintronic applications. Recently, observations of magnetic skyrmions in the 2D ferromagnet Fe3GeTe2 (FGT) have been reported, introducing further application possibilities. However, controlling the exhibited magnetic state requires systematic knowledge of the history-dependence of the spin textures, which remains largely unexplored in 2D magnets. In this work, we utilise real-space imaging, and complementary simulations, to determine and explain the thickness-dependent magnetic phase diagrams of an exfoliated FGT flake, revealing a complex, history-dependent emergence of the uniformly magnetised, stripe domain and skyrmion states. The results show that the interplay of the dominant dipolar interaction and strongly temperature dependent out-of-plane anisotropy energy terms enables the selective stabilisation of all three states at zero field, and at a single temperature, while the Dzyaloshinksii-Moriya interaction must be present to realise the observed Néel-type domain walls. The findings open perspectives for 2D devices incorporating topological spin textures. Fe3GeTe2, known as FGT, is a van der Waals magnetic material that was recently shown to host magnetic skyrmions. Here, Birch et al using both X-ray and electron microscopy to study the stability of skyrmions in FGT, revealing how the sample history can influence skyrmion formation
Collapse
Affiliation(s)
- M T Birch
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany.
| | - L Powalla
- Max Planck Institute for Solid State Research, 70569, Stuttgart, Germany.
| | - S Wintz
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - O Hovorka
- Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - K Litzius
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - J C Loudon
- Department of Materials Science and Metallurgy, University of Cambridge, Cambridge, CB3 0FS, UK
| | - L A Turnbull
- Department of Physics, Durham University, Durham, DH1 3LE, UK
| | - V Nehruji
- Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - K Son
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany.,Department of Physics Education, Kongju National University, Gongju, 32588, South Korea
| | - C Bubeck
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - T G Rauch
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Institut Nanospektroskopie, 12489, Berlin, Germany
| | - M Weigand
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Institut Nanospektroskopie, 12489, Berlin, Germany
| | - E Goering
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - M Burghard
- Max Planck Institute for Solid State Research, 70569, Stuttgart, Germany
| | - G Schütz
- Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| |
Collapse
|
34
|
Kern LM, Pfau B, Deinhart V, Schneider M, Klose C, Gerlinger K, Wittrock S, Engel D, Will I, Günther CM, Liefferink R, Mentink JH, Wintz S, Weigand M, Huang MJ, Battistelli R, Metternich D, Büttner F, Höflich K, Eisebitt S. Deterministic Generation and Guided Motion of Magnetic Skyrmions by Focused He +-Ion Irradiation. NANO LETTERS 2022; 22:4028-4035. [PMID: 35577328 PMCID: PMC9137908 DOI: 10.1021/acs.nanolett.2c00670] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 05/02/2022] [Indexed: 05/18/2023]
Abstract
Magnetic skyrmions are quasiparticles with nontrivial topology, envisioned to play a key role in next-generation data technology while simultaneously attracting fundamental research interest due to their emerging topological charge. In chiral magnetic multilayers, current-generated spin-orbit torques or ultrafast laser excitation can be used to nucleate isolated skyrmions on a picosecond time scale. Both methods, however, produce randomly arranged skyrmions, which inherently limits the precision on the location at which the skyrmions are nucleated. Here, we show that nanopatterning of the anisotropy landscape with a He+-ion beam creates well-defined skyrmion nucleation sites, thereby transforming the skyrmion localization into a deterministic process. This approach allows control of individual skyrmion nucleation as well as guided skyrmion motion with nanometer-scale precision, which is pivotal for both future fundamental studies of skyrmion dynamics and applications.
Collapse
Affiliation(s)
- Lisa-Marie Kern
- Max
Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, 12489 Berlin, Germany
| | - Bastian Pfau
- Max
Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, 12489 Berlin, Germany
- E-mail:
| | - Victor Deinhart
- Max
Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, 12489 Berlin, Germany
- Ferdinand-Braun-Institut
gGmbH, Leibniz-Institut für Höchstfrequenztechnik, 12489 Berlin, Germany
- Helmholtz-Zentrum
für Materialien und Energie GmbH, 14109 Berlin, Germany
| | - Michael Schneider
- Max
Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, 12489 Berlin, Germany
| | - Christopher Klose
- Max
Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, 12489 Berlin, Germany
| | - Kathinka Gerlinger
- Max
Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, 12489 Berlin, Germany
| | - Steffen Wittrock
- Max
Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, 12489 Berlin, Germany
| | - Dieter Engel
- Max
Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, 12489 Berlin, Germany
| | - Ingo Will
- Max
Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, 12489 Berlin, Germany
| | - Christian M. Günther
- Technische
Universität Berlin, Zentraleinrichtung Elektronenmikroskopie (ZELMI), 10623 Berlin, Germany
| | - Rein Liefferink
- Radboud
University, Institute for
Molecules and Materials (IMM), 6525 AJ Nijmegen, Netherlands
| | - Johan H. Mentink
- Radboud
University, Institute for
Molecules and Materials (IMM), 6525 AJ Nijmegen, Netherlands
| | - Sebastian Wintz
- Max
Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - Markus Weigand
- Helmholtz-Zentrum
für Materialien und Energie GmbH, 14109 Berlin, Germany
| | - Meng-Jie Huang
- Deutsches
Elektronen-Synchrotron (DESY), 22607 Hamburg, Germany
| | | | - Daniel Metternich
- Helmholtz-Zentrum
für Materialien und Energie GmbH, 14109 Berlin, Germany
| | - Felix Büttner
- Helmholtz-Zentrum
für Materialien und Energie GmbH, 14109 Berlin, Germany
| | - Katja Höflich
- Ferdinand-Braun-Institut
gGmbH, Leibniz-Institut für Höchstfrequenztechnik, 12489 Berlin, Germany
- Helmholtz-Zentrum
für Materialien und Energie GmbH, 14109 Berlin, Germany
| | - Stefan Eisebitt
- Max
Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, 12489 Berlin, Germany
- Technische
Universität Berlin, Institut für
Optik und Atomare Physik, 10623 Berlin, Germany
| |
Collapse
|
35
|
Tambovtsev IM, Leonov AO, Lobanov IS, Kiselev AD, Uzdin VM. Topological structures in chiral media: Effects of confined geometry. Phys Rev E 2022; 105:034701. [PMID: 35428094 DOI: 10.1103/physreve.105.034701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Accepted: 02/25/2022] [Indexed: 06/14/2023]
Abstract
We theoretically study orientational structures in chiral magnetics and cholesteric liquid crystal (CLC) nanosystems confined in the slab geometry. Our analysis is based on the model that, in addition to the exchange and the Dzyaloshinskii-Moriya interactions, takes into account the bulk and surface anisotropies. In CLC films, these anisotropies describe the energy of interaction with external magnetic/electric field and the anchoring energy assuming that magnetic/electric anisotropy is negative and the boundary conditions are homeotropic. We have computed the phase diagram and found that the ground state of the film is represented by various delocalized structures depending on the bulk and surface anisotropy parameters, κ^{b} and κ^{s}. These include the z helix and the z cone states, the oblique, and the x helicoids. The minimum energy paths connecting the ground state and metastable helicoids and the energy barriers separating these states are evaluated. We have shown that there is a variety of localized topological structures such as the skyrmion tube, the toron, and the bobber that can be embedded in different ground states including the z cone (conical phase) and tilted fingerprint states. We have also found the structure called the leech that can be viewed as an intermediate state between the toron and the skyrmion tube.
Collapse
Affiliation(s)
- I M Tambovtsev
- Department of Physics, St. Petersburg State University, St. Petersburg 198504, Russia and Faculty of Physics, ITMO University, 197101 St. Petersburg, Russia
| | - A O Leonov
- Department of Chemistry, Faculty of Science, Hiroshima University Kagamiyama, Higashi Hiroshima, Hiroshima 739-8526, Japan and IFW Dresden, Postfach 270016, D-01171 Dresden, Germany
| | - I S Lobanov
- Faculty of Physics, ITMO University, 197101 St. Petersburg, Russia
| | - Alexei D Kiselev
- Laboratory of Quantum Processes and Measurements, ITMO University, 199034 St. Petersburg, Russia
| | - V M Uzdin
- Faculty of Physics, ITMO University, 197101 St. Petersburg, Russia and Department of Physics, St. Petersburg State University, St. Petersburg 198504, Russia
| |
Collapse
|
36
|
Chen X, Lin M, Kong JF, Tan HR, Tan AK, Je S, Tan HK, Khoo KH, Im M, Soumyanarayanan A. Unveiling the Emergent Traits of Chiral Spin Textures in Magnetic Multilayers. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2103978. [PMID: 34978165 PMCID: PMC8867163 DOI: 10.1002/advs.202103978] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Indexed: 05/16/2023]
Abstract
Magnetic skyrmions are topologically wound nanoscale textures of spins whose ambient stability and electrical manipulation in multilayer films have led to an explosion of research activities. While past efforts focused predominantly on isolated skyrmions, recently ensembles of chiral spin textures, consisting of skyrmions and magnetic stripes, are shown to possess rich interactions with potential for device applications. However, several fundamental aspects of chiral spin texture phenomenology remain to be elucidated, including their domain wall (DW) structure, thermodynamic stability, and morphological transitions. Here the evolution of these textural characteristics are unveiled on a tunable multilayer platform-wherein chiral interactions governing spin texture energetics can be widely varied-using a combination of full-field electron and soft X-ray microscopies with numerical simulations. With increasing chiral interactions, the emergence of Néel helicity, followed by a marked reduction in domain compressibility, and finally a transformation in the skyrmion formation mechanism are demonstrated. Together with an analytical model, these experiments establish a comprehensive microscopic framework for investigating and tailoring chiral spin texture character in multilayer films.
Collapse
Affiliation(s)
- Xiaoye Chen
- Institute of Materials Research & EngineeringAgency for ScienceTechnology & Research (A*STAR)Singapore138634Singapore
- Data Storage InstituteAgency for ScienceTechnology & Research (A*STAR)Singapore138634Singapore
| | - Ming Lin
- Institute of Materials Research & EngineeringAgency for ScienceTechnology & Research (A*STAR)Singapore138634Singapore
| | - Jian Feng Kong
- Institute of High Performance ComputingAgency for ScienceTechnology & Research (A*STAR)Singapore138632Singapore
| | - Hui Ru Tan
- Institute of Materials Research & EngineeringAgency for ScienceTechnology & Research (A*STAR)Singapore138634Singapore
| | - Anthony K.C. Tan
- Data Storage InstituteAgency for ScienceTechnology & Research (A*STAR)Singapore138634Singapore
| | - Soong‐Geun Je
- Center for X‐Ray OpticsLawrence Berkeley National LaboratoryBerkeleyCA94720USA
| | - Hang Khume Tan
- Institute of Materials Research & EngineeringAgency for ScienceTechnology & Research (A*STAR)Singapore138634Singapore
- Data Storage InstituteAgency for ScienceTechnology & Research (A*STAR)Singapore138634Singapore
| | - Khoong Hong Khoo
- Institute of High Performance ComputingAgency for ScienceTechnology & Research (A*STAR)Singapore138632Singapore
| | - Mi‐Young Im
- Center for X‐Ray OpticsLawrence Berkeley National LaboratoryBerkeleyCA94720USA
| | - Anjan Soumyanarayanan
- Institute of Materials Research & EngineeringAgency for ScienceTechnology & Research (A*STAR)Singapore138634Singapore
- Data Storage InstituteAgency for ScienceTechnology & Research (A*STAR)Singapore138634Singapore
- Department of PhysicsNational University of SingaporeSingapore117551Singapore
| |
Collapse
|
37
|
Kim SK, Beach GSD, Lee KJ, Ono T, Rasing T, Yang H. Ferrimagnetic spintronics. NATURE MATERIALS 2022; 21:24-34. [PMID: 34949868 DOI: 10.1038/s41563-021-01139-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 09/21/2021] [Indexed: 06/14/2023]
Abstract
Ferrimagnets composed of multiple and antiferromagnetically coupled magnetic elements have attracted much attention recently as a material platform for spintronics. They offer the combined advantages of both ferromagnets and antiferromagnets, namely the easy control and detection of their net magnetization by an external field, antiferromagnetic-like dynamics faster than ferromagnetic dynamics and the potential for high-density devices. This Review summarizes recent progress in ferrimagnetic spintronics, with particular attention to the most-promising functionalities of ferrimagnets, which include their spin transport, spin texture dynamics and all-optical switching.
Collapse
Affiliation(s)
- Se Kwon Kim
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
| | - Geoffrey S D Beach
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Kyung-Jin Lee
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea.
- Department of Materials Science and Engineering, Korea University, Seoul, Korea.
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, Korea.
| | - Teruo Ono
- Institute of Chemical Research, Kyoto University, Kyoto, Japan
- Center for Spintronics Research Network (CSRN), Graduate School of Engineering Science, Osaka University, Osaka, Japan
| | - Theo Rasing
- Institute for Molecules and Materials, Radboud University, Nijmegen, the Netherlands
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan, China
| | - Hyunsoo Yang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| |
Collapse
|
38
|
Chen C, Lin T, Niu J, Sun Y, Yang L, Kang W, Lei N. Surface acoustic wave controlled skyrmion-based synapse devices. NANOTECHNOLOGY 2021; 33:115205. [PMID: 34852336 DOI: 10.1088/1361-6528/ac3f14] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 12/01/2021] [Indexed: 06/13/2023]
Abstract
Magnetic skyrmions, which are particle-like spin structures, are promising information carriers for neuromorphic computing devices due to their topological stability and nanoscale size. In this work, we propose controlling magnetic skyrmions by electric-field-excited surface acoustic waves in neuromorphic computing device structures. Our micromagnetic simulations show that the number of created skyrmions, which emulates the synaptic weight parameter, increases monotonically with increases in the amplitude of the surface acoustic waves. Additionally, the efficiency of skyrmion creation is investigated systemically with a wide range of magnetic parameters, and the optimal values are presented accordingly. Finally, the functionalities of short-term plasticity and long-term potentiation are demonstrated via skyrmion excitation by a sequence of surface acoustic waves with different intervals. The application of surface acoustic waves in skyrmionic neuromorphic computing devices paves a novel approach to low-power computing systems.
Collapse
Affiliation(s)
- Chao Chen
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, People's Republic of China
| | - Tao Lin
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, People's Republic of China
| | - Jianteng Niu
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, People's Republic of China
| | - Yiming Sun
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, People's Republic of China
| | - Liu Yang
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, People's Republic of China
| | - Wang Kang
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, People's Republic of China
| | - Na Lei
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, People's Republic of China
| |
Collapse
|
39
|
Rajib MM, Misba WA, Bhattacharya D, Atulasimha J. Robust skyrmion mediated reversal of ferromagnetic nanodots of 20 nm lateral dimension with high M s and observable DMI. Sci Rep 2021; 11:20914. [PMID: 34686742 PMCID: PMC8536757 DOI: 10.1038/s41598-021-99780-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 09/30/2021] [Indexed: 11/18/2022] Open
Abstract
Implementation of skyrmion based energy efficient and high-density data storage devices requires aggressive scaling of skyrmion size. Ferrimagnetic materials are considered to be a suitable platform for this purpose due to their low saturation magnetization (i.e. smaller stray field). However, this method of lowering the saturation magnetization and scaling the lateral size of skyrmions is only applicable where the skyrmions have a smaller lateral dimension compared to the hosting film. Here, we show by performing rigorous micromagnetic simulation that the size of skyrmions, which have lateral dimension comparable to their hosting nanodot can be scaled by increasing saturation magnetization. Also, when the lateral dimension of nanodot is reduced and thereby the skyrmion confined in it is downscaled, there remains a challenge in forming a stable skyrmion with experimentally observed Dzyaloshinskii–Moriya interaction (DMI) values since this interaction has to facilitate higher canting per spin to complete a 360° rotation along the diameter. In our study, we found that skyrmions can be formed in 20 nm lateral dimension nanodots with high saturation magnetization (1.30–1.70 MA/m) and DMI values (~ 3 mJ/m2) that have been reported to date. This result could stimulate experiments on implementation of highly dense skyrmion devices. Additionally, using this, we show that voltage controlled magnetic anisotropy based switching mediated by an intermediate skyrmion state can be achieved in the soft layer of a ferromagnetic p-MTJ of lateral dimensions 20 nm with sub 1 fJ/bit energy in the presence of room temperature thermal noise with reasonable DMI ~ 3 mJ/m2.
Collapse
Affiliation(s)
- Md Mahadi Rajib
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA, 23284, USA
| | - Walid Al Misba
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA, 23284, USA
| | - Dhritiman Bhattacharya
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA, 23284, USA
| | - Jayasimha Atulasimha
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA, 23284, USA. .,Department of Electrical and Computer Engineering, Virginia Commonwealth University, Richmond, VA, 23284, USA.
| |
Collapse
|
40
|
Skyrmion Formation in Nanodisks Using Magnetic Force Microscopy Tip. NANOMATERIALS 2021; 11:nano11102627. [PMID: 34685062 PMCID: PMC8538463 DOI: 10.3390/nano11102627] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 09/13/2021] [Accepted: 09/28/2021] [Indexed: 01/19/2023]
Abstract
We demonstrated numerically the skyrmion formation in ultrathin nanodisks using a magnetic force microscopy tip. We found that the local magnetic field generated by the magnetic tip significantly affects the magnetization state of the nanodisks and leads to the formation of skyrmions. Experimentally, we confirmed the influence of the local field on the magnetization states of the disks. Micromagnetic simulations explain the evolution of the magnetic state during magnetic force microscopy scanning and confirm the possibility of skyrmion formation. The formation of the horseshoe magnetic domain is a key transition from random labyrinth domain states into the skyrmion state. We showed that the formation of skyrmions by the magnetic probe is a reliable and repetitive procedure. Our findings provide a simple solution for skyrmion formation in nanodisks.
Collapse
|
41
|
Quessab Y, Xu J, Morshed MG, Ghosh AW, Kent AD. Interplay between Spin-Orbit Torques and Dzyaloshinskii-Moriya Interactions in Ferrimagnetic Amorphous Alloys. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:e2100481. [PMID: 34338450 PMCID: PMC8456276 DOI: 10.1002/advs.202100481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 06/29/2021] [Indexed: 06/13/2023]
Abstract
Ferrimagnetic thin films are attractive for low-power spintronic applications because of their low magnetization, small angular momentum, and fast spin dynamics. Spin orbit torques (SOT) can be applied with proximal heavy metals that also generate interfacial Dzyaloshinskii-Moriya interactions (DMI), which can stabilize ultrasmall skyrmions and enable fast domain wall motion. Here, the properties of a ferrimagnetic CoGd alloy between two heavy metals to increase the SOT efficiency, while maintaining a significant DMI is studied. SOT switching for various capping layers and alloy compositions shows that Pt/CoGd/(W or Ta) films enable more energy-efficient SOT magnetization switching than Pt/CoGd/Ir. Spin-torque ferromagnetic resonance confirms that Pt/CoGd/W has the highest spin-Hall angle of 16.5%, hence SOT efficiency, larger than Pt/CoGd/(Ta or Ir). Density functional theory calculations indicate that CoGd films capped by W or Ta have the largest DMI energy, 0.38 and 0.32 mJ m-2 , respectively. These results show that Pt/CoGd/W is a very promising ferrimagnetic structure to achieve small skyrmions and to move them efficiently with current.
Collapse
Affiliation(s)
- Yassine Quessab
- Center for Quantum Phenomena, Department of PhysicsNew York UniversityNew YorkNY10003USA
| | - Jun‐Wen Xu
- Center for Quantum Phenomena, Department of PhysicsNew York UniversityNew YorkNY10003USA
| | - Md Golam Morshed
- Department of Electrical and Computer EngineeringUniversity of VirginiaCharlottesvilleVA22904USA
| | - Avik W. Ghosh
- Department of Electrical and Computer EngineeringUniversity of VirginiaCharlottesvilleVA22904USA
- Department of PhysicsUniversity of VirginiaCharlottesvilleVirginia22904USA
| | - Andrew D. Kent
- Center for Quantum Phenomena, Department of PhysicsNew York UniversityNew YorkNY10003USA
| |
Collapse
|
42
|
Kim TH, Zhao H, Ong PV, Jensen BA, Cui B, King AH, Ke L, Zhou L. Kinetics of Magnetic Skyrmion Crystal Formation from the Conical Phase. NANO LETTERS 2021; 21:5547-5554. [PMID: 34185540 DOI: 10.1021/acs.nanolett.1c00923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The particle-like magnetic skyrmion or skyrmion lattice (SkX) formation has promoted strong application and fundamental science interests. Despite extensive research, the kinetic of the SkX development is much less understood because of the ultrafast spin rotation and high sensitivity to external perturbations. Here, using in situ Lorentz transmission electron microscopy, we successfully measured the dynamics of SkX formation from the conical phase with precise control of both the temperature and the magnetic field. We discovered that the Avrami equation can accurately describe the transition process with an initial Avrami constant around 1, suggesting that the rate-limiting step for the quasiparticle lattice formation is one-dimensional heterogeneous nucleation of individual skyrmions. A modified Arrhenius rate law is established, with an energy barrier that has a square-root dependence on temperature and a quadratic dependence on the magnetic field. This study paves the way toward precise and predictable manipulation of topological spin structures.
Collapse
Affiliation(s)
- Tae-Hoon Kim
- Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011, United States
- Department of Materials Science and Engineering, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Haijun Zhao
- School of Physics, Southeast University, Nanjing 211189, China
| | - Phuong-Vu Ong
- Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011, United States
| | - Brandt A Jensen
- Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011, United States
| | - Baozhi Cui
- Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011, United States
| | - Alexander H King
- Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011, United States
- Department of Materials Science and Engineering, Iowa State University, Ames, Iowa 50011, United States
| | - Liqin Ke
- Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011, United States
| | - Lin Zhou
- Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011, United States
| |
Collapse
|
43
|
Deriving the skyrmion Hall angle from skyrmion lattice dynamics. Nat Commun 2021; 12:2723. [PMID: 33976177 PMCID: PMC8113591 DOI: 10.1038/s41467-021-22857-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 03/30/2021] [Indexed: 11/08/2022] Open
Abstract
Magnetic skyrmions are topologically non-trivial, swirling magnetization textures that form lattices in helimagnetic materials. These magnetic nanoparticles show promise as high efficiency next-generation information carriers, with dynamics that are governed by their topology. Among the many unusual properties of skyrmions is the tendency of their direction of motion to deviate from that of a driving force; the angle by which they diverge is a materials constant, known as the skyrmion Hall angle. In magnetic multilayer systems, where skyrmions often appear individually, not arranging themselves in a lattice, this deflection angle can be easily measured by tracing the real space motion of individual skyrmions. Here we describe a reciprocal space technique which can be used to determine the skyrmion Hall angle in the skyrmion lattice state, leveraging the properties of the skyrmion lattice under a shear drive. We demonstrate this procedure to yield a quantitative measurement of the skyrmion Hall angle in the room-temperature skyrmion system FeGe, shearing the skyrmion lattice with the magnetic field gradient generated by a single turn Oersted wire. Skyrmions, when driven by any applied force, experience an addition sideways motion known as the skyrmion hall effect. Here, Brearton et al. present a reciprocal space method for determining the strength of the skyrmion hall effect, making measurement possible for skyrmion lattices.
Collapse
|
44
|
Derras-Chouk A, Chudnovsky EM. Skyrmions near defects. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:195802. [PMID: 33540401 DOI: 10.1088/1361-648x/abe351] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 02/04/2021] [Indexed: 06/12/2023]
Abstract
We study the impact of an exchange-reducing defect on a skyrmion in a thin film of finite thickness. Attraction of the skyrmion to a defect is demonstrated in a lattice model by computing the micromagnetic energy accounting for the exchange, Dzyaloshinskii-Moriya interaction, magnetic anisotropy, and dipole-dipole coupling. The spiraling dynamics of the skyrmion toward the defect is illustrated by solving numerically the full Landau-Lifshitz-Gilbert equations on a lattice and, independently, by solving the Thiele equation, with the two methods in agreement with each other. Depinning of the skyrmion by the current is investigated. We find that the skyrmion deforms when it is close to the defect. Deformation is small in the parameter space far from the phase boundary that determines stability of skyrmions. It increases dramatically near the phase boundary, leading to the transformation of the skyrmion by the defect into a snake-like magnetic domain.
Collapse
Affiliation(s)
- Amel Derras-Chouk
- Physics Department, Herbert H. Lehman College and Graduate School, The City University of New York, 250 Bedford Park Boulevard West, Bronx, New York 10468-1589, United States of America
| | - Eugene M Chudnovsky
- Physics Department, Herbert H. Lehman College and Graduate School, The City University of New York, 250 Bedford Park Boulevard West, Bronx, New York 10468-1589, United States of America
| |
Collapse
|
45
|
Subterahertz collective dynamics of polar vortices. Nature 2021; 592:376-380. [PMID: 33854251 DOI: 10.1038/s41586-021-03342-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 02/08/2021] [Indexed: 02/02/2023]
Abstract
The collective dynamics of topological structures1-6 are of interest from both fundamental and applied perspectives. For example, studies of dynamical properties of magnetic vortices and skyrmions3,4 have not only deepened our understanding of many-body physics but also offered potential applications in data processing and storage7. Topological structures constructed from electrical polarization, rather than electron spin, have recently been realized in ferroelectric superlattices5,6, and these are promising for ultrafast electric-field control of topological orders. However, little is known about the dynamics underlying the functionality of such complex extended nanostructures. Here, using terahertz-field excitation and femtosecond X-ray diffraction measurements, we observe ultrafast collective polarization dynamics that are unique to polar vortices, with orders-of-magnitude higher frequencies and smaller lateral size than those of experimentally realized magnetic vortices3. A previously unseen tunable mode, hereafter referred to as a vortexon, emerges in the form of transient arrays of nanoscale circular patterns of atomic displacements, which reverse their vorticity on picosecond timescales. Its frequency is considerably reduced (softened) at a critical strain, indicating a condensation (freezing) of structural dynamics. We use first-principles-based atomistic calculations and phase-field modelling to reveal the microscopic atomic arrangements and corroborate the frequencies of the vortex modes. The discovery of subterahertz collective dynamics in polar vortices opens opportunities for electric-field-driven data processing in topological structures with ultrahigh speed and density.
Collapse
|
46
|
Petrović AP, Raju M, Tee XY, Louat A, Maggio-Aprile I, Menezes RM, Wyszyński MJ, Duong NK, Reznikov M, Renner C, Milošević MV, Panagopoulos C. Skyrmion-(Anti)Vortex Coupling in a Chiral Magnet-Superconductor Heterostructure. PHYSICAL REVIEW LETTERS 2021; 126:117205. [PMID: 33798341 DOI: 10.1103/physrevlett.126.117205] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Accepted: 01/14/2021] [Indexed: 06/12/2023]
Abstract
We report experimental coupling of chiral magnetism and superconductivity in [IrFeCoPt]/Nb heterostructures. The stray field of skyrmions with radius ≈50 nm is sufficient to nucleate antivortices in a 25 nm Nb film, with unique signatures in the magnetization, critical current, and flux dynamics, corroborated via simulations. We also detect a thermally tunable Rashba-Edelstein exchange coupling in the isolated skyrmion phase. This realization of a strongly interacting skyrmion-(anti)vortex system opens a path toward controllable topological hybrid materials, unattainable to date.
Collapse
Affiliation(s)
- A P Petrović
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371 Singapore
| | - M Raju
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371 Singapore
| | - X Y Tee
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371 Singapore
| | - A Louat
- Department of Physics, Technion, Haifa 32000, Israel
| | - I Maggio-Aprile
- Department of Quantum Matter Physics, Université de Genève, 24 Quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland
| | - R M Menezes
- Department of Physics, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium
- Departamento de Física, Universidade Federal de Pernambuco, Cidade Universitária, 50670-901 Recife-PE, Brazil
| | - M J Wyszyński
- Department of Physics, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium
| | - N K Duong
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371 Singapore
| | - M Reznikov
- Department of Physics, Technion, Haifa 32000, Israel
| | - Ch Renner
- Department of Quantum Matter Physics, Université de Genève, 24 Quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland
| | - M V Milošević
- Department of Physics, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium
| | - C Panagopoulos
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371 Singapore
| |
Collapse
|
47
|
Antiferromagnetic half-skyrmions and bimerons at room temperature. Nature 2021; 590:74-79. [PMID: 33536652 DOI: 10.1038/s41586-021-03219-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 11/16/2020] [Indexed: 01/30/2023]
Abstract
In the quest for post-CMOS (complementary metal-oxide-semiconductor) technologies, driven by the need for improved efficiency and performance, topologically protected ferromagnetic 'whirls' such as skyrmions1-8 and their anti-particles have shown great promise as solitonic information carriers in racetrack memory-in-logic or neuromorphic devices1,9-11. However, the presence of dipolar fields in ferromagnets, which restricts the formation of ultrasmall topological textures3,6,8,9,12, and the deleterious skyrmion Hall effect, when skyrmions are driven by spin torques9,10,12, have thus far inhibited their practical implementation. Antiferromagnetic analogues, which are predicted to demonstrate relativistic dynamics, fast deflection-free motion and size scaling, have recently become the subject of intense focus9,13-19, but they have yet to be experimentally demonstrated in natural antiferromagnetic systems. Here we realize a family of topological antiferromagnetic spin textures in α-Fe2O3-an Earth-abundant oxide insulator-capped with a platinum overlayer. By exploiting a first-order analogue of the Kibble-Zurek mechanism20,21, we stabilize exotic merons and antimerons (half-skyrmions)8 and their pairs (bimerons)16,22, which can be erased by magnetic fields and regenerated by temperature cycling. These structures have characteristic sizes of the order of 100 nanometres and can be chemically controlled via precise tuning of the exchange and anisotropy, with pathways through which further scaling may be achieved. Driven by current-based spin torques from the heavy-metal overlayer, some of these antiferromagnetic textures could emerge as prime candidates for low-energy antiferromagnetic spintronics at room temperature1,9-11,23.
Collapse
|
48
|
Büttner F, Pfau B, Böttcher M, Schneider M, Mercurio G, Günther CM, Hessing P, Klose C, Wittmann A, Gerlinger K, Kern LM, Strüber C, von Korff Schmising C, Fuchs J, Engel D, Churikova A, Huang S, Suzuki D, Lemesh I, Huang M, Caretta L, Weder D, Gaida JH, Möller M, Harvey TR, Zayko S, Bagschik K, Carley R, Mercadier L, Schlappa J, Yaroslavtsev A, Le Guyarder L, Gerasimova N, Scherz A, Deiter C, Gort R, Hickin D, Zhu J, Turcato M, Lomidze D, Erdinger F, Castoldi A, Maffessanti S, Porro M, Samartsev A, Sinova J, Ropers C, Mentink JH, Dupé B, Beach GSD, Eisebitt S. Observation of fluctuation-mediated picosecond nucleation of a topological phase. NATURE MATERIALS 2021; 20:30-37. [PMID: 33020615 DOI: 10.1038/s41563-020-00807-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 08/20/2020] [Indexed: 06/11/2023]
Abstract
Topological states of matter exhibit fascinating physics combined with an intrinsic stability. A key challenge is the fast creation of topological phases, which requires massive reorientation of charge or spin degrees of freedom. Here we report the picosecond emergence of an extended topological phase that comprises many magnetic skyrmions. The nucleation of this phase, followed in real time via single-shot soft X-ray scattering after infrared laser excitation, is mediated by a transient topological fluctuation state. This state is enabled by the presence of a time-reversal symmetry-breaking perpendicular magnetic field and exists for less than 300 ps. Atomistic simulations indicate that the fluctuation state largely reduces the topological energy barrier and thereby enables the observed rapid and homogeneous nucleation of the skyrmion phase. These observations provide fundamental insights into the nature of topological phase transitions, and suggest a path towards ultrafast topological switching in a wide variety of materials through intermediate fluctuating states.
Collapse
Affiliation(s)
- Felix Büttner
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Helmholtz-Zentrum für Materialien und Energie GmbH, Berlin, Germany.
| | | | - Marie Böttcher
- Institut für Physik, Johannes Gutenberg Universität Mainz, Mainz, Germany
| | | | | | - Christian M Günther
- Zentraleinrichtung Elektronenmikroskopie (ZELMI), Technische Universität Berlin, Berlin, Germany
- Institut für Optik und Atomare Physik, Technische Universität Berlin, Berlin, Germany
| | | | | | - Angela Wittmann
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | | | | | | | | | | | | | - Alexandra Churikova
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Siying Huang
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Daniel Suzuki
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Ivan Lemesh
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Mantao Huang
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Lucas Caretta
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | | | - John H Gaida
- 4th Physical Institute, University of Göttingen, Göttingen, Germany
| | - Marcel Möller
- 4th Physical Institute, University of Göttingen, Göttingen, Germany
| | - Tyler R Harvey
- 4th Physical Institute, University of Göttingen, Göttingen, Germany
| | - Sergey Zayko
- 4th Physical Institute, University of Göttingen, Göttingen, Germany
| | - Kai Bagschik
- Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany
| | | | | | | | | | | | | | | | | | | | | | - Jun Zhu
- European XFEL, Schenefeld, Germany
| | | | | | - Florian Erdinger
- Institute of Computer Engineering, Heidelberg University, Heidelberg, Germany
| | - Andrea Castoldi
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano, Italy
- Istituto Nazionale di Fisica Nucleare, Sezione di Milano, Milano, Italy
| | | | | | | | - Jairo Sinova
- Institut für Physik, Johannes Gutenberg Universität Mainz, Mainz, Germany
| | - Claus Ropers
- 4th Physical Institute, University of Göttingen, Göttingen, Germany
| | - Johan H Mentink
- Institute for Molecules and Materials, Radboud University, Nijmegen, the Netherlands
| | - Bertrand Dupé
- Institut für Physik, Johannes Gutenberg Universität Mainz, Mainz, Germany
- Nanomat/Q-mat/CESAM, Université de Liège, Belgium and Fonds de la Recherche Scientifique (FNRS), Bruxelles, Belgium
| | - Geoffrey S D Beach
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Stefan Eisebitt
- Max-Born-Institut, Berlin, Germany
- Institut für Optik und Atomare Physik, Technische Universität Berlin, Berlin, Germany
| |
Collapse
|
49
|
Chen K, Lott D, Philippi-Kobs A, Weigand M, Luo C, Radu F. Observation of compact ferrimagnetic skyrmions in DyCo 3 film. NANOSCALE 2020; 12:18137-18143. [PMID: 32852506 DOI: 10.1039/d0nr02947e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Owing to the experimental discovery of magnetic skyrmions stabilized by the Dzyaloshinskii-Moriya and/or dipolar interactions in thin films, there is a recent upsurge of interest in magnetic skyrmions with antiferromagnetic spins in order to overcome the fundamental limitations inherent with skyrmions in ferromagnetic materials. Here, we report on the observation of compact ferrimagnetic skyrmions for the class of amorphous alloys consisting of 4f rare-earth and 3d transition-metal elements with perpendicular magnetic anisotropy, using a DyCo3 film, that are identified by combining X-ray magnetic scattering, scanning transmission X-ray microscopy, and Hall transport technique. These skyrmions, with antiparallel aligned Dy and Co magnetic moments and a characteristic core radius of about 40 nm, are formed during the nucleation and annihilation of the magnetic maze-like domain pattern exhibiting a topological Hall effect contribution. Our findings provide a promising route for fundamental research in the field of ferrimagnetic/antiferromagnetic spintronics towards practical applications.
Collapse
Affiliation(s)
- K Chen
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Str. 15, 12489 Berlin, Germany.
| | | | | | | | | | | |
Collapse
|
50
|
Strain-enhanced Dzyaloshinskii-Moriya interaction at Co/Pt interfaces. Sci Rep 2020; 10:12314. [PMID: 32704010 PMCID: PMC7378838 DOI: 10.1038/s41598-020-69360-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 07/10/2020] [Indexed: 11/08/2022] Open
Abstract
The interfacial Dzyaloshinskii-Moriya interaction (DMI) is an essential ingredient for stabilizing chiral spin configurations in spintronic applications. Here, via first-principles calculations, we reveal the influence of lattice strain on DMI in Co/Pt interface. We observed a considerable enhancement for a certain lattice strain. Furthermore, a direct correlation is established between the DMI and interlayer distances dominated by the strain, which is attributed to a hybridization of electronic orbitals. This hybridization has also been presented as the microscopic origin of the interfacial DMI. We anticipate that our predictions provide new insights into the control of interfacial DMI for skyrmion-based spintronic devices.
Collapse
|