1
|
Jin H, Chen J, van der Laan G, Hesjedal T, Liu Y, Zhang S. Rolling Motion of Rigid Skyrmion Crystallites Induced by Chiral Lattice Torque. NANO LETTERS 2024; 24:12226-12232. [PMID: 39297736 DOI: 10.1021/acs.nanolett.4c03336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/03/2024]
Abstract
Magnetic skyrmions are topologically protected spin textures with emergent particle-like behaviors. Their dynamics under external stimuli is of great interest and importance for topological physics and spintronics applications alike. So far, skyrmions are only found to move linearly in response to a linear drive, following the conventional model treating them as isolated quasiparticles. Here, by performing time and spatially resolved resonant elastic X-ray scattering of the insulating chiral magnet Cu2OSeO3, we show that for finite-sized skyrmion crystallites, a purely linear temperature gradient not only propels the skyrmions but also induces continuous rotational motion through a chiral lattice torque. Consequently, a skyrmion crystallite undergoes a rolling motion under a small gradient, while both the rolling speed and the rotational sense can be controlled. Our findings offer a new degree of freedom for manipulating these quasiparticles toward device applications and underscore the fundamental phase difference between the condensed skyrmion lattice and isolated skyrmions.
Collapse
Affiliation(s)
- Haonan Jin
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 200031, China
- ShanghaiTech Laboratory for Topological Physics, ShanghaiTech University, Shanghai 200031, China
| | - Jingyi Chen
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 200031, China
| | - Gerrit van der Laan
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE, United Kingdom
| | - Thorsten Hesjedal
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, United Kingdom
| | - Yizhou Liu
- Anhui Province Key Laboratory of Low-Energy Quantum Materials and Devices, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - Shilei Zhang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 200031, China
- ShanghaiTech Laboratory for Topological Physics, ShanghaiTech University, Shanghai 200031, China
- Center for Transformative Science, ShanghaiTech University, Shanghai 200031, China
| |
Collapse
|
2
|
Hou C, Sun Y, Lu Y, Li Z, Ni J. Regulating magnetic skyrmions in multiferroic monolayer MnOBr. NANOSCALE 2024. [PMID: 39354809 DOI: 10.1039/d4nr02308k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/03/2024]
Abstract
Two-dimensional multiferroic materials that exhibit both ferroelectricity and ferromagnetism provide a new platform for the discovery and regulation of magnetic skyrmions. In this study, we utilize first-principles calculations and Monte Carlo simulations to explore the properties and regulation of magnetic skyrmions in a novel multiferroic monolayer, MnOBr. MnOBr exhibits skyrmions without the need for an external magnetic field. Upon applying an external magnetic field, we found the disappearance of labyrinth domains and the formation of a periodic arrangement of the skyrmion lattice. By employing machine learning techniques, we depict a phase diagram of MnOBr under varying magnetic fields and biaxial strain, which provides a detailed depiction of phase transitions of spin textures in monolayer MnOBr. Furthermore, in MnOBr/CdClBr heterostructures, we demonstrate that the creation and annihilation of magnetic skyrmions can be controlled by switching the polarization direction of the Janus CdClBr. These findings show potential applications of MnOBr as a 2D magnetic skyrmion material in spintronic devices.
Collapse
Affiliation(s)
- Cong Hou
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China.
- Frontier Science Center for Quantum Information, Beijing 100084, China
| | - Yibo Sun
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China.
- Frontier Science Center for Quantum Information, Beijing 100084, China
| | - Yuhang Lu
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China.
- Frontier Science Center for Quantum Information, Beijing 100084, China
| | - Zimo Li
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China.
- Frontier Science Center for Quantum Information, Beijing 100084, China
| | - Jun Ni
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China.
- Frontier Science Center for Quantum Information, Beijing 100084, China
| |
Collapse
|
3
|
Zhao X, Liang H, Ren L, Pang X. Optical skyrmion and its "zipper-like" topological behavior in an energy flux field. OPTICS LETTERS 2024; 49:5391-5394. [PMID: 39352963 DOI: 10.1364/ol.537923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2024] [Accepted: 09/03/2024] [Indexed: 10/04/2024]
Abstract
The optical skyrmion and its topological behavior are analyzed in an energy flux field constructed by an X-type vortex in a high numerical aperture system. The conditions for the formation of a skyrmion structure in this field are discussed, showing that the vortex pattern of the transverse energy flow and the inverse energy flow are crucial for the skyrmions and also are controlled by the phase gradient of the X-type vortex. Notably, the "zipper-like" topological reaction, which is the first, to our knowledge, found in ferromagnetic materials, is observed, and the physical mechanism is also explained by the relation of orbital angular momentum density and Poynting vectors. The results will reach the topological theory and may have applications in optical traps and data storage.
Collapse
|
4
|
Mallick S, Sassi Y, Prestes NF, Krishnia S, Gallego F, M Vicente Arche L, Denneulin T, Collin S, Bouzehouane K, Thiaville A, Dunin-Borkowski RE, Jeudy V, Fert A, Reyren N, Cros V. Driving skyrmions in flow regime in synthetic ferrimagnets. Nat Commun 2024; 15:8472. [PMID: 39349476 PMCID: PMC11443098 DOI: 10.1038/s41467-024-52210-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 08/29/2024] [Indexed: 10/02/2024] Open
Abstract
The last decade has seen significant improvements in our understanding of skyrmions current induced dynamics, along with their room temperature stabilization, however, the impact of local material inhomogeneities still remains an issue that impedes reaching the regime of steady state motion of these spin textures. Here, we study the spin-torque driven motion of skyrmions in synthetic ferrimagnetic multilayers with the aim of achieving high mobility and reduced skyrmion Hall effect. We consider Pt|Co|Tb multilayers of various thicknesses with antiferromagnetic coupling between the Co and Tb magnetization. The increase of Tb thickness in the multilayers reduces the total magnetic moment and increases the spin-orbit torques allowing to reach velocities up to 400 ms-1 for skyrmions with diameters of about 160 nm. We demonstrate that due to reduced skyrmion Hall effect combined with the edge repulsion of the magnetic track, the skyrmions move along the track without any transverse deflection. Further, by comparing the field-induced domain wall motion and current-induced skyrmion motion, we demonstrate that the skyrmions at the largest current densities present all the characteristics of a dynamical flow regime.
Collapse
Affiliation(s)
- Sougata Mallick
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, Palaiseau, France.
- Department of Physics and Nanotechnology, College of Engineering and Technology, SRM Institute of Science and Technology, Kattankulathur, Tamil Nadu, India.
| | - Yanis Sassi
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, Palaiseau, France
| | | | - Sachin Krishnia
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, Palaiseau, France
| | - Fernando Gallego
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, Palaiseau, France
| | - Luis M Vicente Arche
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, Palaiseau, France
| | - Thibaud Denneulin
- Forschungszentrum Jülich, ER-C for Microscopy and Spectroscopy with Electrons, Jülich, Germany
| | - Sophie Collin
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, Palaiseau, France
| | - Karim Bouzehouane
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, Palaiseau, France
| | - André Thiaville
- Laboratoire de Physique des Solides, CNRS, Université Paris-Saclay, Orsay, France
| | - Rafal E Dunin-Borkowski
- Forschungszentrum Jülich, ER-C for Microscopy and Spectroscopy with Electrons, Jülich, Germany
| | - Vincent Jeudy
- Laboratoire de Physique des Solides, CNRS, Université Paris-Saclay, Orsay, France
| | - Albert Fert
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, Palaiseau, France
| | - Nicolas Reyren
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, Palaiseau, France
| | - Vincent Cros
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, Palaiseau, France.
| |
Collapse
|
5
|
Garrido-Tamayo MA, Saavedra E, Saji C, Guevara U, Pérez LM, Pedraja-Rejas L, Díaz P, Laroze D. Stability and Spin Waves of Skyrmion Tubes in Curved FeGe Nanowires. NANOMATERIALS (BASEL, SWITZERLAND) 2024; 14:1468. [PMID: 39330625 PMCID: PMC11434351 DOI: 10.3390/nano14181468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2024] [Revised: 08/30/2024] [Accepted: 09/05/2024] [Indexed: 09/28/2024]
Abstract
In this work, we investigate the influence of curvature on the dynamic susceptibility in FeGe nanowires, both curved and straight, hosting a skyrmionic tube texture under the action of an external bias field, using micromagnetic simulations. Our results demonstrate that both the resonance frequencies and the number of resonant peaks are highly dependent on the curvature of the system. To further understand the nature of the spin wave modes, we analyze the spatial distributions of the resonant mode amplitudes and phases, describing the differences among resonance modes observed. The ability to control the dynamic properties and frequencies of these nanostructures underscores their potential application in frequency-selective magnetic devices.
Collapse
Affiliation(s)
| | - Eduardo Saavedra
- Departamento de Física, Universidad de Santiago de Chile (USACH), Santiago 9170124, Chile
| | - Carlos Saji
- Departamento de Física, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Santiago 8370449, Chile;
| | - Ulises Guevara
- Instituto de Alta Investigación, Universidad de Tarapacá, Casilla 7D, Arica 1000000, Chile; (U.G.); (D.L.)
| | - Laura M. Pérez
- Departamento de Ingeniería Industrial y de Sistemas, Universidad de Tarapacá, Casilla 7D, Arica 1000000, Chile; (L.M.P.); (L.P.-R.)
| | - Liliana Pedraja-Rejas
- Departamento de Ingeniería Industrial y de Sistemas, Universidad de Tarapacá, Casilla 7D, Arica 1000000, Chile; (L.M.P.); (L.P.-R.)
| | - Pablo Díaz
- Departamento de Ciencias Físicas, Universidad de La Frontera, Casilla 54-D, Temuco 4811230, Chile;
| | - David Laroze
- Instituto de Alta Investigación, Universidad de Tarapacá, Casilla 7D, Arica 1000000, Chile; (U.G.); (D.L.)
| |
Collapse
|
6
|
Guang Y, Zhang X, Liu Y, Peng L, Yasin FS, Karube K, Nakamura D, Nagaosa N, Taguchi Y, Mochizuki M, Tokura Y, Yu X. Confined antiskyrmion motion driven by electric current excitations. Nat Commun 2024; 15:7701. [PMID: 39227610 PMCID: PMC11371833 DOI: 10.1038/s41467-024-52072-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2024] [Accepted: 08/23/2024] [Indexed: 09/05/2024] Open
Abstract
Current-driven dynamics of topological spin textures, such as skyrmions and antiskyrmions, have garnered considerable attention in condensed matter physics and spintronics. As compared with skyrmions, the current-driven dynamics of their antiparticles - antiskyrmions - remain less explored due to the increased complexity of antiskyrmions. Here, we design and employ fabricated microdevices of a prototypical antiskyrmion host, (Fe0.63Ni0.3Pd0.07)3P, to allow in situ current application with Lorentz transmission electron microscopy observations. The experimental results and related micromagnetic simulations demonstrate current-driven antiskyrmion dynamics confined within stripe domains. Under nanosecond-long current pulses, antiskyrmions exhibit directional motion along the stripe regardless of the current direction, while the antiskyrmion velocity is linearly proportional to the current density. Significantly, the antiskyrmion mobility could be enhanced when the current flow is perpendicular to the stripe direction. Our findings provide novel and reliable insights on dynamical antiskyrmions and their potential implications on spintronics.
Collapse
Affiliation(s)
- Yao Guang
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Japan.
| | - Xichao Zhang
- Department of Applied Physics, Waseda University, Tokyo, Japan
| | - Yizhou Liu
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Japan
| | - Licong Peng
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Japan
| | | | - Kosuke Karube
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Japan
| | | | - Naoto Nagaosa
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Japan
- Fundamental Quantum Science Program, TRIP Headquarters, RIKEN, Wako, Japan
| | | | | | - Yoshinori Tokura
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Japan
- Department of Applied Physics, The University of Tokyo, Tokyo, Japan
- Tokyo College, The University of Tokyo, Tokyo, Japan
| | - Xiuzhen Yu
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Japan.
| |
Collapse
|
7
|
Zhang X, Wan G, Zhang J, Zhang YF, Pan J, Du S. Eliminating Skyrmion Hall Effect in Ferromagnetic Skyrmions. NANO LETTERS 2024; 24:10796-10804. [PMID: 39190460 DOI: 10.1021/acs.nanolett.4c02060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/28/2024]
Abstract
Skyrmion Hall effect (SkHE) remains an obstacle for the application of magnetic skyrmions. While methods have been established to cancel or compensate SkHE in artificial antiferromagnets and ferrimagnets, eliminating intrinsic SkHE in ferromagnets is still a big challenge. Here, we propose a strategy to eliminate SkHE by intercalating nonmagnetic elements into van der Waals bilayer ferromagnets featuring in-plane ferromagnetism. The in-plane magnetism, along with a delicate balance among exchange interactions, Dzyaloshinskii-Moriya interactions (DMI), and magnetocrystalline anisotropy, creates interlayer bimerons/quadmerons, whose polarity can be controlled by DMI. Opposite DMI in the upper and lower layers results in opposite polarity and topological charge number Q-locking of topological spin texture, therefore, eliminating the SkHE. By intercalating Sr (Ba) in bilayer VSe2, we identify ten topological magnetic structures with zero topological charge number. Furthermore, we present a phase diagram illustrating diverse magnetic configurations achievable within the bimagnetic atomic layer, offering valuable guidance for future investigations.
Collapse
Affiliation(s)
- Xudan Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guolin Wan
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jie Zhang
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yan-Fang Zhang
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jinbo Pan
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shixuan Du
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| |
Collapse
|
8
|
Birch MT, Belopolski I, Fujishiro Y, Kawamura M, Kikkawa A, Taguchi Y, Hirschberger M, Nagaosa N, Tokura Y. Dynamic transition and Galilean relativity of current-driven skyrmions. Nature 2024; 633:554-559. [PMID: 39294350 DOI: 10.1038/s41586-024-07859-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Accepted: 07/19/2024] [Indexed: 09/20/2024]
Abstract
The coupling of conduction electrons and magnetic textures leads to quantum transport phenomena described by the language of emergent electromagnetic fields1-3. For magnetic skyrmions, spin-swirling particle-like objects, an emergent magnetic field is produced by their topological winding4-6, resulting in the conduction electrons exhibiting the topological Hall effect (THE)7. When the skyrmion lattice (SkL) acquires a drift velocity under conduction electron flow, an emergent electric field is also generated8,9. The resulting emergent electrodynamics dictate the magnitude of the THE by the relative motion of SkL and conduction electrons. Here we report the emergent electrodynamics induced by SkL motion in Gd2PdSi3, facilitated by its giant THE10,11. With increasing current excitation, we observe the dynamic transition of the SkL motion from the pinned to creep regime and finally to the flow regime, in which the THE is totally suppressed. We argue that the Galilean relativity required for the total cancellation of the THE may be generically recovered in the flow regime, even in complex multiband systems such as the present compound. Moreover, the observed THE voltages are large enough to enable real-time measurement of the SkL velocity-current profile, which shows the inertial-like motion of the SkL in the creep regime, appearing as the current hysteresis of the skyrmion velocity.
Collapse
Affiliation(s)
- Max T Birch
- RIKEN Center for Emergent Matter Science (CEMS), Wakō, Japan.
| | - Ilya Belopolski
- RIKEN Center for Emergent Matter Science (CEMS), Wakō, Japan
| | | | - Minoru Kawamura
- RIKEN Center for Emergent Matter Science (CEMS), Wakō, Japan
| | - Akiko Kikkawa
- RIKEN Center for Emergent Matter Science (CEMS), Wakō, Japan
| | | | - Max Hirschberger
- RIKEN Center for Emergent Matter Science (CEMS), Wakō, Japan
- Department of Applied Physics, University of Tokyo, Tokyo, Japan
| | - Naoto Nagaosa
- RIKEN Center for Emergent Matter Science (CEMS), Wakō, Japan.
- RIKEN Fundamental Quantum Science Program, Wakō, Japan.
| | - Yoshinori Tokura
- RIKEN Center for Emergent Matter Science (CEMS), Wakō, Japan.
- Department of Applied Physics, University of Tokyo, Tokyo, Japan.
- Tokyo College, University of Tokyo, Tokyo, Japan.
| |
Collapse
|
9
|
Yang L, Savchenko AS, Zheng F, Kiselev NS, Rybakov FN, Han X, Blügel S, Dunin-Borkowski RE. Embedded Skyrmion Bags in Thin Films of Chiral Magnets. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2403274. [PMID: 39045913 DOI: 10.1002/adma.202403274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 06/25/2024] [Indexed: 07/25/2024]
Abstract
Magnetic skyrmions are topologically nontrivial spin configurations that possess particle-like properties. Earlier research has mainly focused on a specific type of skyrmion with topological charge Q = -1. However, theoretical analyses of 2D chiral magnets have predicted the existence of skyrmion bags-solitons with arbitrary positive or negative topological charge. Although such spin textures are metastable states, recent experimental observations have confirmed the stability of isolated skyrmion bags in a limited range of applied magnetic fields. Here, by utilizing Lorentz transmission electron microscopy, the extraordinary stability of skyrmion bags in thin plates of B20-type FeGe is shown. In particular, it is shown that skyrmion bags embedded within a skyrmion lattice remain stable even in zero or inverted external magnetic fields. A robust protocol for nucleating such embedded skyrmion bags is provided. The results agree perfectly with micromagnetic simulations and establish thin plates of cubic chiral magnets as a powerful platform for exploring a broad spectrum of topological magnetic solitons.
Collapse
Affiliation(s)
- Luyan Yang
- Beijing Key Laboratory of Microstructure and Property of Advanced Materials, College of Materials Science and Engineering, Beijing University of Technology, Beijing, 100124, China
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Andrii S Savchenko
- Peter Grünberg Institute, Forschungszentrum Jülich and JARA, 52425, Jülich, Germany
| | - Fengshan Zheng
- Spin-X Institute, Center for Electron Microscopy, School of Physics and Optoelectronics, State Key Laboratory of Luminescent Materials and Devices, Guangdong-Hong Kong-Macao Joint Laboratory of Optoelectronic and Magnetic Functional Materials, South China University of Technology, Guangzhou, 511442, China
| | - Nikolai S Kiselev
- Peter Grünberg Institute, Forschungszentrum Jülich and JARA, 52425, Jülich, Germany
| | - Filipp N Rybakov
- Department of Physics and Astronomy, Uppsala University, Box-516, Uppsala, SE-751 20, Sweden
| | - Xiaodong Han
- Beijing Key Laboratory of Microstructure and Property of Advanced Materials, College of Materials Science and Engineering, Beijing University of Technology, Beijing, 100124, China
- Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Stefan Blügel
- Peter Grünberg Institute, Forschungszentrum Jülich and JARA, 52425, Jülich, Germany
| | - Rafal E Dunin-Borkowski
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich, 52425, Jülich, Germany
| |
Collapse
|
10
|
Sun W, Zhou N, Chen W, Sheng Z, Wu H. Acoustic Skyrmionic Mode Coupling and Transferring in a Chain of Subwavelength Metastructures. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2401370. [PMID: 38981042 PMCID: PMC11425862 DOI: 10.1002/advs.202401370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Revised: 05/02/2024] [Indexed: 07/11/2024]
Abstract
Skyrmions, a stable topological vectorial textures characteristic with skyrmionic number, hold promise for advanced applications in information storage and transmission. While the dynamic motion control of skyrmions has been realized with various techniques in magnetics and optics, the manipulation of acoustic skyrmion has not been done. Here, the propagation and control of acoustic skyrmion along a chain of metastructures are shown. In coupled acoustic resonators made with Archimedes spiral channel, the skyrmion hybridization is found giving rise to bonding and antibonding skyrmionic modes. Furthermore, it is experimentally observed that the skyrmionic mode of acoustic velocity field distribution can be robustly transferred covering a long distance and almost no distortion of the skyrmion textures in a chain of metastructures, even if a structure defect is introduced in the travel path. The proposed localized acoustic skyrmionic mode coupling and propagating is expected in future applications for manipulating acoustic information storage and transfer.
Collapse
Affiliation(s)
- Wen‐Jun Sun
- School of Mechanics and Photoelectric PhysicsAnhui University of Science and TechnologyHuainan232001China
| | - Nong Zhou
- School of Mechanics and Photoelectric PhysicsAnhui University of Science and TechnologyHuainan232001China
| | - Wan‐Na Chen
- School of Mechanics and Photoelectric PhysicsAnhui University of Science and TechnologyHuainan232001China
| | - Zong‐Qiang Sheng
- School of Mechanics and Photoelectric PhysicsAnhui University of Science and TechnologyHuainan232001China
| | - Hong‐Wei Wu
- School of Mechanics and Photoelectric PhysicsAnhui University of Science and TechnologyHuainan232001China
- Center for Fundamental PhysicsAnhui University of Science and TechnologyHuainan232001China
- Institute of EnergyHefei Comprehensive National Science Center (Anhui Energy Laboratory)Hefei230031China
| |
Collapse
|
11
|
Garanin DA, Soriano JF, Chudnovsky EM. Melting and freezing of a skyrmion lattice. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:475802. [PMID: 39142350 DOI: 10.1088/1361-648x/ad6f8b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2024] [Accepted: 08/14/2024] [Indexed: 08/16/2024]
Abstract
We report comprehensive Monte-Carlo studies of the melting of skyrmion lattices (SkL) in systems of small, medium, and large sizes with the number of skyrmions ranging from 103to over 105. Large systems exhibit hysteresis similar to that observed in real experiments on the melting of SkLs. For sufficiently small systems which achieve thermal equilibrium, a fully reversible sharp solid-liquid transition on temperature with no intermediate hexatic phase is observed. A similar behavior is found on changing the magnetic field that provides the control of pressure in the SkL. We find that on heating the melting transition occurs via a formation of grains with different orientations of hexagonal axes. On cooling, the fluctuating grains coalesce into larger clusters until a uniform orientation of hexagonal axes is slowly established. The observed scenario is caused by collective effects involving defects and is more complex than a simple picture of a transition driven by the unbinding and annihilation of dislocation and disclination pairs.
Collapse
Affiliation(s)
- Dmitry A Garanin
- Physics Department, Herbert H. Lehman College and Graduate School, The City University of New York, 250 Bedford Park Boulevard West, Bronx, NY 10468-1589, United States of America
| | - Jorge F Soriano
- Physics Department, Herbert H. Lehman College and Graduate School, The City University of New York, 250 Bedford Park Boulevard West, Bronx, NY 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, NY 10468-1589, United States of America
| |
Collapse
|
12
|
Xie YM, Liu Y, Nagaosa N. Sliding Dynamics of Current-Driven Skyrmion Crystal and Helix in Chiral Magnets. PHYSICAL REVIEW LETTERS 2024; 133:096702. [PMID: 39270189 DOI: 10.1103/physrevlett.133.096702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 05/27/2024] [Accepted: 07/24/2024] [Indexed: 09/15/2024]
Abstract
The skyrmion crystal (SkX) and helix (HL) phases, present in typical chiral magnets, can each be considered as forms of density waves but with distinct topologies. The SkX exhibits gyrodynamics analogous to electrons under a magnetic field, while the HL state resembles topological trivial spin density waves. However, unlike the charge density waves, the theoretical analysis of the sliding motion of SkX and HL remains unclear, especially regarding the similarities and differences in sliding dynamics between these two spin density waves. In this Letter, we systematically explore the sliding dynamics of SkX and HL in chiral magnets in the limit of large current density. We demonstrate that the sliding dynamics of both SkX and HL can be unified within the same theoretical framework as density waves, despite their distinct microscopic orders. Furthermore, we highlight the significant role of gyrotropic sliding induced by impurity effects in the SkX state, underscoring the impact of nontrivial topology on the sliding motion of density waves. Our theoretical analysis shows that the effect of impurity pinning is much stronger in HL compared with SkX, i.e., χ^{SkX}/χ^{HL}∼α^{2} (χ^{SkX}, χ^{HL}: susceptibility to the impurity potential, α (≪1) is the Gilbert damping). Moreover, the velocity correction is mostly in the transverse direction to the current in SkX. These results are further substantiated by realistic Landau-Lifshitz-Gilbert simulations.
Collapse
|
13
|
Bhattacharjee S, Lee SC. Magnetization dynamics in skyrmions due to high-speed carrier injections from Dirac half-metals. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:475801. [PMID: 39142328 DOI: 10.1088/1361-648x/ad6f65] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2024] [Accepted: 08/14/2024] [Indexed: 08/16/2024]
Abstract
Recent developments in the magnetization dynamics in spin textures, particularly skyrmions, offer promising new directions for magnetic storage technologies and spintronics. Skyrmions, characterized by their topological protection and efficient mobility at low current density, are increasingly recognized for their potential applications in next-generation logic and memory devices. This study investigates the dynamics of skyrmion magnetization, focusing on the manipulation of their topological states as a basis for bitwise data storage through a modified Landau-Lifshitz-Gilbert equation (LLG). We introduce spin-polarized electrons from a topological ferromagnet that induce an electric dipole moment that interacts with the electric gauge field within the skyrmion domain. This interaction creates an effective magnetic field that results in a torque that can dynamically change the topological state of the skyrmion. In particular, we show that these torques can selectively destroy and create skyrmions, effectively writing and erasing bits, highlighting the potential of using controlled electron injection for robust and scalable skyrmion-based data storage solutions.
Collapse
Affiliation(s)
| | - Seung-Cheol Lee
- Electronic Materials Research Center, Korea Institute of Science & Technology, Seoul, Republic of Korea
| |
Collapse
|
14
|
Lee WG, Lee JH. A Deterministic Method to Construct a Common Supercell Between Two Similar Crystalline Surfaces. SMALL METHODS 2024:e2400579. [PMID: 39192466 DOI: 10.1002/smtd.202400579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2024] [Revised: 08/04/2024] [Indexed: 08/29/2024]
Abstract
Here, a deterministic algorithm is proposed, that is capable of constructing a common supercell between two similar crystalline surfaces without scanning all possible cases. Using the complex plane, the 2D lattice is defined as the 2D complex vector. Then, the relationship between two surfaces becomes the eigenvector-eigenvalue relation where an operator corresponds to a transformation matrix. It is shown that this transformation matrix can be directly determined from the lattice parameters and rotation angle of the two given crystalline surfaces with O(log Nmax) time complexity, where Nmax is the maximum index of repetition matrix elements. This process is much faster than the conventional brute force approach (O ( N max 4 ) $O(N_{\mathrm{max}}^4)$ ). By implementing the method in Python code, experimental 2D heterostructures and their moiré patterns and additionally find new moiré patterns that have not yet been reported are successfully generated. According to the density functional theory (DFT) calculations, some of the new moiré patterns are expected to be as stable as experimentally-observed moiré patterns. Taken together, it is believed that the method can be widely applied as a useful tool for designing new heterostructures with interesting properties.
Collapse
Affiliation(s)
- Weon-Gyu Lee
- Computational Science Research Center, Korean Institute of Science and Technology (KIST), Seoul, 02792, South Korea
- inCerebro Co., Ltd, Seoul, 06234, South Korea
| | - Jung-Hoon Lee
- Computational Science Research Center, Korean Institute of Science and Technology (KIST), Seoul, 02792, South Korea
| |
Collapse
|
15
|
Wang S, Zhou Z, Zheng Z, Sun J, Cao H, Song S, Deng ZL, Qin F, Cao Y, Li X. Topological Structures of Energy Flow: Poynting Vector Skyrmions. PHYSICAL REVIEW LETTERS 2024; 133:073802. [PMID: 39213555 DOI: 10.1103/physrevlett.133.073802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 05/29/2024] [Accepted: 07/16/2024] [Indexed: 09/04/2024]
Abstract
Topological properties of energy flow of light are fundamentally interesting and may introduce novel physical phenomena associated with directional light scattering and optical trapping. In this Letter, skyrmionlike structures formed by Poynting vectors are unveiled in the focal region of two pairs of counterpropagating cylindrical vector vortex beams in free space. The appearance of local phase singularities, and the distinct traveling and standing wave modes of different field components passing through the focal spot lead to a Néel-Bloch-Néel transition of Poynting vector skyrmion textures along the light propagating direction. By shaping the wave front of the incident beams with patterned amplitudes, the topological invariant of the Poynting vector skyrmions can be further tuned in a prospective area. This work expands the family of optical skyrmions and holds great potential in energy flow associated applications.
Collapse
Affiliation(s)
- Sicong Wang
- Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou 510632, China and College of Physics & Optoelectronic Engineering, Jinan University, Guangzhou 510632, China
| | - Zhikai Zhou
- Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou 510632, China and College of Physics & Optoelectronic Engineering, Jinan University, Guangzhou 510632, China
| | - Zecan Zheng
- Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou 510632, China and College of Physics & Optoelectronic Engineering, Jinan University, Guangzhou 510632, China
| | - Jialin Sun
- Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou 510632, China and College of Physics & Optoelectronic Engineering, Jinan University, Guangzhou 510632, China
| | - Hongkun Cao
- Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou 510632, China and College of Physics & Optoelectronic Engineering, Jinan University, Guangzhou 510632, China
| | - Shichao Song
- Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou 510632, China and College of Physics & Optoelectronic Engineering, Jinan University, Guangzhou 510632, China
| | - Zi-Lan Deng
- Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou 510632, China and College of Physics & Optoelectronic Engineering, Jinan University, Guangzhou 510632, China
| | - Fei Qin
- Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou 510632, China and College of Physics & Optoelectronic Engineering, Jinan University, Guangzhou 510632, China
| | - Yaoyu Cao
- Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou 510632, China and College of Physics & Optoelectronic Engineering, Jinan University, Guangzhou 510632, China
| | - Xiangping Li
- Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou 510632, China and College of Physics & Optoelectronic Engineering, Jinan University, Guangzhou 510632, China
| |
Collapse
|
16
|
Zhao L, Hua C, Song C, Yu W, Jiang W. Realization of skyrmion shift register. Sci Bull (Beijing) 2024; 69:2370-2378. [PMID: 38960814 DOI: 10.1016/j.scib.2024.05.035] [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: 10/17/2023] [Revised: 04/15/2024] [Accepted: 05/23/2024] [Indexed: 07/05/2024]
Abstract
The big data explosion demands novel data storage technology. Among many different approaches, solitonic racetrack memory devices hold great promise for accommodating nonvolatile and low-power functionalities. As representative topological solitons, magnetic skyrmions are envisioned as potential information carriers for efficient information processing. While their advantages as memory and logic elements have been vastly exploited from theoretical perspectives, the corresponding experimental efforts are rather limited. These challenges, which are key to versatile skyrmionic devices, will be studied in this work. Through patterning concaved surface topography with designed arrays of indentations on standard Si/SiO2 substrates, we demonstrate that the resultant non-flat energy landscape could lead to the formation of hexagonal and square skyrmion lattices in Ta/CoFeB/MgO multilayers. Based on these films, one-dimensional racetrack devices are subsequently fabricated, in which a long-distance deterministic shifting of skyrmions between neighboring indentations is achieved at room temperature. Through separating the word line and the bit line, a prototype shift register device, which can sequentially generate and precisely shift complex skyrmionic data strings, is presented. The deterministic writing and long-distance shifting of skyrmionic bits can find potential applications in transformative skyrmionic memory, logic as well as the in-memory computing devices.
Collapse
Affiliation(s)
- Le Zhao
- 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
| | - Chensong Hua
- State Key Laboratory of Surface Physics and Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, China; Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai 201210, 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
| | - Weichao Yu
- State Key Laboratory of Surface Physics and Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, China; Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai 201210, 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.
| |
Collapse
|
17
|
Verma RS, Raj RK, Verma G, Kaushik BK. Energy-efficient synthetic antiferromagnetic skyrmion-based artificial neuronal device. NANOTECHNOLOGY 2024; 35:435401. [PMID: 39084230 DOI: 10.1088/1361-6528/ad6997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Accepted: 07/31/2024] [Indexed: 08/02/2024]
Abstract
Magnetic skyrmions offer unique characteristics such as nanoscale size, particle-like behavior, topological stability, and low depinning current density. These properties make them promising candidates for next-generation spintronics-based memory and neuromorphic computing. However, one of their distinctive features is their tendency to deviate from the direction of the applied driving force that may lead to the skyrmion annihilation at the edge of nanotrack during skyrmion motion, known as the skyrmion Hall effect (SkHE). To overcome this problem, synthetic antiferromagnetic (SAF) skyrmions that having bilayer coupling effect allows them to follow a straight path by nullifying SkHE making them alternative for ferromagnetic (FM) counterpart. This study proposes an integrate-and-fire (IF) artificial neuron model based on SAF skyrmions with asymmetric wedge-shaped nanotrack having self-sustainability of skyrmion numbers at the device window. The model leverages inter-skyrmion repulsion to replicate the IF mechanism of biological neuron. The device threshold, determined by the maximum number of pinned skyrmions at the device window, can be adjusted by tuning the current density applied to the nanotrack. Neuronal spikes occur when initial skyrmion reaches the detection unit after surpassing the device window by the accumulation of repulsive force that result in reduction of the device's contriving current results to design of high energy efficient for neuromorphic computing. Furthermore, work implements a binarized neuronal network accelerator using proposed IF neuron and SAF-SOT-MRAM based synaptic devices for national institute of standards and technology database image classification. The presented approach achieves significantly higher energy efficiency compared to existing technologies like SRAM and STT-MRAM, with improvements of 2.31x and 1.36x, respectively. The presented accelerator achieves 1.42x and 1.07x higher throughput efficiency per Watt as compared to conventional SRAM and STT-MRAM based designs.
Collapse
Affiliation(s)
- Ravi Shankar Verma
- Department of Electronics and Communication Engineering, Indian Institute of Technology, Roorkee 247667, India
| | - Ravish Kumar Raj
- Department of Electronics and Communication Engineering, Indian Institute of Technology, Roorkee 247667, India
| | - Gaurav Verma
- 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
|
18
|
Gonçalves MAP, Paściak M, Hlinka J. Antiskyrmions in Ferroelectric Barium Titanate. PHYSICAL REVIEW LETTERS 2024; 133:066802. [PMID: 39178440 DOI: 10.1103/physrevlett.133.066802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 05/16/2024] [Accepted: 06/21/2024] [Indexed: 08/25/2024]
Abstract
Typical magnetic skyrmion is a string of inverted magnetization within a ferromagnet, protected by a sleeve of a vortexlike spin texture, such that its cross-section carries an integer topological charge. Some magnets form antiskyrmions, the antiparticle strings which carry an opposite topological charge. Here we demonstrate that topologically equivalent but purely electric antiskyrmion can exist in a ferroelectric material as well. In particular, our computer experiments reveal that the archetype ferroelectric, barium titanate, can host antiskyrmions at zero field. The polarization pattern around their cores reminds ring windings of decorative knots rather than the typical magnetic antiskyrmion texture. We show that the antiskyrmion of barium titanate has just 2-3 nm in diameter, a hexagonal cross section, and an exotic topological charge with doubled magnitude and opposite sign when compared to the standard skyrmion string.
Collapse
|
19
|
He Z, Li Z, Chen Z, Wang Z, Shen J, Wang S, Song C, Zhao T, Cai J, Lin SZ, Zhang Y, Shen B. Experimental observation of current-driven antiskyrmion sliding in stripe domains. NATURE MATERIALS 2024; 23:1048-1054. [PMID: 38605194 DOI: 10.1038/s41563-024-01870-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Accepted: 03/18/2024] [Indexed: 04/13/2024]
Abstract
Magnetic skyrmions are promising as next-generation information units. Their antiparticle-the antiskyrmion-has also been discovered in chiral magnets. Here we experimentally demonstrate antiskyrmion sliding in response to a pulsed electric current at room temperature without the requirement of an external magnetic field. This is realized by embedding antiskyrmions in helical stripe domains, which naturally provide one-dimensional straight tracks along which antiskyrmion sliding can be easily launched with low current density and without transverse deflection from the antiskyrmion Hall effect. The higher mobility of the antiskyrmions in the background of helical stripes in contrast to the typical ferromagnetic state is a result of intrinsic material parameters and elastic energy of the stripe domain, thereby smearing out the random pinning potential, as supported by micromagnetic simulations. The demonstration and comprehensive understanding of antiskyrmion movement along naturally straight tracks offers a new perspective for (anti)skyrmion application in spintronics.
Collapse
Affiliation(s)
- Zhidong He
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Zhuolin Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Zhaohui Chen
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing, China
| | - Zhan Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Jun Shen
- Department of Energy and Power Engineering, School of Mechanical Engineering, Beijing Institute of Technology, Beijing, China
| | - Shouguo Wang
- Anhui Key Laboratory of Magnetic Functional Materials and Devices, School of Materials Science and Engineering, Anhui University, Hefei, China
| | - Cheng Song
- Key Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing, China
| | - Tongyun Zhao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Jianwang Cai
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Shi-Zeng Lin
- Theoretical Division and Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, USA.
| | - Ying Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China.
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China.
- Songshan Lake Materials Laboratory, Dongguan, China.
| | - Baogen Shen
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
- Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, Ningbo, China
| |
Collapse
|
20
|
Cai N, Liu Y. Skyrmions Subtractor Based on Dzyaloshinskii-Moriya Interaction Gate. J Phys Chem Lett 2024; 15:7775-7781. [PMID: 39047264 DOI: 10.1021/acs.jpclett.4c01542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2024]
Abstract
Skyrmions are increasingly favored in developing various spintronic devices as efficient information carriers. The proposed voltage-controlled Dzyaloshinskii-Moriya interaction (VCDM) offers an additional means to manipulate the movement of skyrmions. In this study, we investigated how the skyrmions behave when passing through the VCDM gate in ferromagnetic nanotracks driven by current. Our findings suggest that reducing the strength of the Dzyaloshinskii-Moriya interaction (DMI) can more effectively block skyrmions, while increasing the DMI strength can more effectively attract them. This indicates that the motion behavior of skyrmions can be controlled by changing the shape of the VCDM gate, thereby demonstrating the effectiveness of VCDM gates in controlling skyrmion motion. Due to the ability of VCDM gates to block skyrmions, we have designed a robust subtractor based on skyrmions. These results provide valuable insights for the development of future skyrmion-based devices using the DMI method.
Collapse
Affiliation(s)
- Na Cai
- College of Sciences, Northeastern University, Shenyang 110819, People's Republic of China
| | - Yan Liu
- College of Sciences, Northeastern University, Shenyang 110819, People's Republic of China
| |
Collapse
|
21
|
Roychowdhury S, Yanda P, Samanta K, Yi C, Yao M, Orlandi F, Manuel P, Khalyavin D, Valle EGD, Constantinou P, Strocov VN, Vergniory MG, Shekhar C, Felser C. Giant Room-Temperature Topological Hall Effect in a Square-Net Ferromagnet LaMn 2Ge 2. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2305916. [PMID: 39004883 DOI: 10.1002/adma.202305916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 07/03/2024] [Indexed: 07/16/2024]
Abstract
A topological magnetic material showcases a multitude of intriguing properties resulting from the compelling interplay between topology and magnetism. These include notable phenomena such as a large anomalous Nernst effect (ANE), an anomalous Hall effect (AHE), and a topological Hall effect (THE). In most cases, topological transport phenomena are prevalent at temperatures considerably lower than room temperature, presenting a challenge for practical applications. However, the noncollinear ferromagnetic (FM) LaMn2Ge2, characterized by a Mn square-net lattice and a notably high Curie temperature (TC) of approximately 325 K, defies this trend as a topological semimetal. This work observes a giant topological Hall resistivity,ρ y x T $\rho _{yx}^T$ , of ≈4.5 µΩ cm at room temperature when the angle between the applied field and the c-axis is 75°, which is significantly higher than state-of-the-art materials with noncoplanar spin structures. The single crystal neutron diffraction measurements agree with an incommensurate conical magnetic structure as the ground state. This observation suggests the enhanced spin chirality resulting from the noncoplanar spin configuration when the applied field is away from the magnetic easy axis as the origin of a large contribution to the observed THE. The findings unequivocally demonstrate that the FM LaMn2Ge2 holds great promise as a potential topological semimetal for spintronic applications even at room temperature.
Collapse
Affiliation(s)
- Subhajit Roychowdhury
- Max Planck Institute for Chemical Physics of Solids, 01187, Dresden, Germany
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal, 462066, India
| | - Premakumar Yanda
- Max Planck Institute for Chemical Physics of Solids, 01187, Dresden, Germany
| | - Kartik Samanta
- Max Planck Institute for Chemical Physics of Solids, 01187, Dresden, Germany
| | - Changjiang Yi
- Max Planck Institute for Chemical Physics of Solids, 01187, Dresden, Germany
| | - Mengyu Yao
- Max Planck Institute for Chemical Physics of Solids, 01187, Dresden, Germany
| | - Fabio Orlandi
- ISIS Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot, OX11 0QX, UK
| | - Pascal Manuel
- ISIS Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot, OX11 0QX, UK
| | - Dmitry Khalyavin
- ISIS Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot, OX11 0QX, UK
| | | | | | - Vladimir N Strocov
- Swiss Light Source, Paul Scherrer Institute, Villigen, CH-5232, Switzerland
| | - Maia G Vergniory
- Max Planck Institute for Chemical Physics of Solids, 01187, Dresden, Germany
- Donostia International Physics Center, Donostia-San Sebastian, 20018, Spain
| | - Chandra Shekhar
- Max Planck Institute for Chemical Physics of Solids, 01187, Dresden, Germany
| | - Claudia Felser
- Max Planck Institute for Chemical Physics of Solids, 01187, Dresden, Germany
| |
Collapse
|
22
|
Kim J, Kim Y, Sung D, Hong S. Valley-Dependent Electronic Properties of Metal Monochalcogenides GaX and Janus Ga 2XY (X, Y = S, Se, and Te). NANOMATERIALS (BASEL, SWITZERLAND) 2024; 14:1295. [PMID: 39120400 PMCID: PMC11313789 DOI: 10.3390/nano14151295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2024] [Revised: 07/10/2024] [Accepted: 07/12/2024] [Indexed: 08/10/2024]
Abstract
Two-dimensional (2D) materials have shown outstanding potential for new devices based on their interesting electrical properties beyond conventional 3D materials. In recent years, new concepts such as the valley degree of freedom have been studied to develop valleytronics in hexagonal lattice 2D materials. We investigated the valley degree of freedom of GaX and Janus GaXY (X, Y = S, Se, Te). By considering the spin-orbit coupling (SOC) effect in the band structure calculations, we identified the Rashba-type spin splitting in band structures of Janus Ga2SSe and Ga2STe. Further, we confirmed that the Zeeman-type spin splitting at the K and K' valleys of GaX and Janus Ga2XY show opposite spin contributions. We also calculated the Berry curvatures of GaX and Janus GaXY. In this study, we find that GaX and Janus Ga2XY have a similar magnitude of Berry curvatures, while having opposite signs at the K and K' points. In particular, GaTe and Ga2SeTe have relatively larger Berry curvatures of about 3.98 Å2 and 3.41 Å2, respectively, than other GaX and Janus Ga2XY.
Collapse
Affiliation(s)
| | | | | | - Suklyun Hong
- Department of Physics, Graphene Research Institute, Quantum Information Science and Technology Center, Sejong University, Seoul 05006, Republic of Korea
| |
Collapse
|
23
|
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
|
24
|
Guo Y, Zhuo F, Li H. Influence of the Hall-bar geometry on texture-induced topological spin transport in two-dimensional Rashba spin-orbit ferromagnets. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:415801. [PMID: 38959901 DOI: 10.1088/1361-648x/ad5eea] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Accepted: 07/03/2024] [Indexed: 07/05/2024]
Abstract
While the recent prediction and observation of magnetic skyrmions bears inspiring promise for next-generation spintronic devices, how to detect and track their position becomes an important issue. In this work, we investigate the spin transport in a two-dimensional magnetic nanoribbon with the Hall-bar geometry in the presence of Rashba spin-orbit coupling and magnetic skyrmions. We employ the Kwant tight-binding code to compute the Hall conductance and local spin-polarized current density. We consider two versions of the model: One with single skyrmion and one with two separate skyrmions. It is found that the size and position of the skyrmions strongly modulate the Hall conductance near the Hall-bar position. The geometry of the Hall bar also has a strong influence on the Hall conductance of the system. With the decreasing of the width of Hall leads, the peak of Hall conductance becomes sharper. We also show the spatial distribution of the spin-polarized current density around a skyrmion located at different positions. We extend this study toward two separate skyrmions, where the Hall conductance also reveals a sizable dependence on the position of the skyrmions and their distance. Our numerical analysis offers the possibility of electrically detecting the skyrmion position, which could have potential applications in ultrahigh-density storage design.
Collapse
Affiliation(s)
- Yufei Guo
- School of Physics and Electronics, Henan University, Kaifeng 475004, People's Republic of China
| | - Fengjun Zhuo
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, People's Republic of China
| | - Hang Li
- School of Physics and Electronics, Henan University, Kaifeng 475004, People's Republic of China
| |
Collapse
|
25
|
Dong Y, Arai Y, Kuroda K, Ochi M, Tanaka N, Wan Y, Watson MD, Kim TK, Cacho C, Hashimoto M, Lu D, Aoki Y, Matsuda TD, Kondo T. Fermi Surface Nesting Driving the RKKY Interaction in the Centrosymmetric Skyrmion Magnet Gd_{2}PdSi_{3}. PHYSICAL REVIEW LETTERS 2024; 133:016401. [PMID: 39042805 DOI: 10.1103/physrevlett.133.016401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 05/06/2024] [Accepted: 05/22/2024] [Indexed: 07/25/2024]
Abstract
The magnetic skyrmions generated in a centrosymmetric crystal were recently first discovered in Gd_{2}PdSi_{3}. In light of this, we observe the electronic structure by angle-resolved photoemission spectroscopy and unveil its direct relationship with the magnetism in this compound. The Fermi surface and band dispersions are demonstrated to have a good agreement with the density functional theory calculations carried out with careful consideration of the crystal superstructure. Most importantly, we find that the three-dimensional Fermi surface has extended nesting which matches well the q vector of the magnetic order detected by recent scattering measurements. The consistency we find among angle-resolved photoemission spectroscopy, density functional theory, and the scattering measurements suggests the Ruderman-Kittel-Kasuya-Yosida interaction involving itinerant electrons to be the formation mechanism of skyrmions in Gd_{2}PdSi_{3}.
Collapse
Affiliation(s)
| | | | - Kenta Kuroda
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
- Graduate School of Advanced Science and Engineering, Hiroshima University, Higashi-hiroshima, Hiroshima 739-8526, Japan
- International Institute for Sustainability with Knotted Chiral Meta Matter (WPI-SKCM), Hiroshima University, Higashi-hiroshima, Hiroshima 739-8526, Japan
- Research Institute for Semiconductor Engineering, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8527, Japan
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
26
|
Song D, Wang W, Zhang S, Liu Y, Wang N, Zheng F, Tian M, Dunin-Borkowski RE, Zang J, Du H. Steady motion of 80-nm-size skyrmions in a 100-nm-wide track. Nat Commun 2024; 15:5614. [PMID: 38965221 PMCID: PMC11224351 DOI: 10.1038/s41467-024-49976-6] [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: 03/21/2024] [Accepted: 06/27/2024] [Indexed: 07/06/2024] Open
Abstract
The current-driven movement of magnetic skyrmions along a nanostripe is essential for the advancement and functionality of a new category of spintronic devices resembling racetracks. Despite extensive research into skyrmion dynamics, experimental verification of current-induced motion of ultra-small skyrmions within an ultrathin nanostripe is still pending. Here, we unveil the motion of individual 80 nm-size skyrmions in an FeGe track with an ultrathin width of 100 nm. The skyrmions can move steadily along the track over a broad range of current densities by using controlled pulse durations of as low as 2 ns. The potential landscape, arising from the magnetic edge twists in such a geometrically confined system, introduces skyrmion inertia and ensures efficient motion with a vanishing skyrmion Hall angle. Our results showcase the steady motion of skyrmions in an ultrathin track, offering a practical pathway for implementing skyrmion-based spintronic devices.
Collapse
Affiliation(s)
- Dongsheng Song
- Institutes of Physical Science and Information Technology, Anhui University, Hefei, 230601, China.
- Anhui Province Key Laboratory of Low-Energy Quantum Materials and Devices, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences, Hefei, Anhui, 230031, China.
| | - Weiwei Wang
- Institutes of Physical Science and Information Technology, Anhui University, Hefei, 230601, China
- Anhui Province Key Laboratory of Low-Energy Quantum Materials and Devices, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences, Hefei, Anhui, 230031, China
| | - Shuisen Zhang
- Anhui Province Key Laboratory of Low-Energy Quantum Materials and Devices, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences, Hefei, Anhui, 230031, China
- University of Science and Technology of China, Hefei, 230026, China
| | - Yizhou Liu
- Anhui Province Key Laboratory of Low-Energy Quantum Materials and Devices, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences, Hefei, Anhui, 230031, China
| | - Ning Wang
- Anhui Province Key Laboratory of Low-Energy Quantum Materials and Devices, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences, Hefei, Anhui, 230031, China
| | - Fengshan Zheng
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425, Jülich, Germany
- Spin-X Institute, Center for Electron Microscopy, School of Physics and Optoelectronics State Key Laboratory of Luminescent Materials and Devices Guangdong-Hong Kong-Macao Joint Laboratory of Optoelectronic and Magnetic Functional Materials, South China University of Technology, Guangzhou, 511442, P. R. China
| | - Mingliang Tian
- Anhui Province Key Laboratory of Low-Energy Quantum Materials and Devices, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences, Hefei, Anhui, 230031, China
- Science Island Branch of Graduate School, University of Science and Technology of China, Hefei, Anhui, 230026, China
- School of Physics and Optoelectronic Engineering, Anhui University, Hefei, 230601, China
| | - Rafal E Dunin-Borkowski
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Jiadong Zang
- Department of Physics and Astronomy, University of New Hampshire, Durham, NH, 03824, USA
- Materials Science Program, University of New Hampshire, Durham, NH, 03824, USA
| | - Haifeng Du
- Institutes of Physical Science and Information Technology, Anhui University, Hefei, 230601, China.
- Anhui Province Key Laboratory of Low-Energy Quantum Materials and Devices, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences, Hefei, Anhui, 230031, China.
- Science Island Branch of Graduate School, University of Science and Technology of China, Hefei, Anhui, 230026, China.
| |
Collapse
|
27
|
Lone AH, Zou X, Mishra KK, Singaravelu V, Sbiaa R, Fariborzi H, Setti G. Multilayer ferromagnetic spintronic devices for neuromorphic computing applications. NANOSCALE 2024; 16:12431-12444. [PMID: 38904318 DOI: 10.1039/d4nr01003e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/22/2024]
Abstract
Based on ferromagnetic thin film systems, spintronic devices show substantial prospects for energy-efficient memory, logic, and unconventional computing paradigms. This paper presents a multilayer ferromagnetic spintronic device's experimental and micromagnetic simulation-based realization for neuromorphic computing applications. The device exhibits a temperature-dependent magnetic field and current-controlled multilevel resistance state switching. To study the scalability of the multilayer spintronic devices for neuromorphic applications, we further simulated the scaled version of the multilayer system read using the magnetic tunnel junction (MTJ) configuration down to 64 nm width. We show the device applications in hardware neural networks using the multiple resistance states as the synaptic weights. A varying pulse amplitude scheme is also proposed to improve the device's weight linearity. The simulated device shows an energy dissipation of 1.23 fJ for a complete potentiation/depression. The neural network based on these devices was trained and tested on the MNIST dataset using a supervised learning algorithm. When integrated as a weight into a 3-layer, fully connected neural network, these devices achieve recognition accuracy above 90% on the MNIST dataset. Thus, the proposed device demonstrates significant potential for neuromorphic computing applications.
Collapse
Affiliation(s)
- Aijaz H Lone
- Division of Computer, Electrical and Mathematical Sciences and Engineering (CEMSE), King Abdullah University of Science and Technology (KAUST), Saudi Arabia.
| | - Xuecui Zou
- Division of Computer, Electrical and Mathematical Sciences and Engineering (CEMSE), King Abdullah University of Science and Technology (KAUST), Saudi Arabia.
| | - Kishan K Mishra
- Division of Computer, Electrical and Mathematical Sciences and Engineering (CEMSE), King Abdullah University of Science and Technology (KAUST), Saudi Arabia.
| | - Venkatesh Singaravelu
- Nanofabrication Core Lab, King Abdullah University of Science and Technology (KAUST), Saudi Arabia
| | - R Sbiaa
- Department of Physics, College of Science, Sultan Qaboos University, PO Box 36, PC 123 Muscat, Oman
| | - Hossein Fariborzi
- Division of Computer, Electrical and Mathematical Sciences and Engineering (CEMSE), King Abdullah University of Science and Technology (KAUST), Saudi Arabia.
| | - Gianluca Setti
- Division of Computer, Electrical and Mathematical Sciences and Engineering (CEMSE), King Abdullah University of Science and Technology (KAUST), Saudi Arabia.
| |
Collapse
|
28
|
Mochizuki M. Writing a magnetic whirl on multiferroics. NATURE MATERIALS 2024; 23:872-873. [PMID: 38956346 DOI: 10.1038/s41563-024-01923-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2024]
|
29
|
Pankratova M, Eriksson O, Bergman A. Zero-field magnetic skyrmions in exchange-biased ferromagnetic-antiferromagnetic bilayers. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:385803. [PMID: 38848725 DOI: 10.1088/1361-648x/ad5598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Accepted: 06/07/2024] [Indexed: 06/09/2024]
Abstract
We report on the stabilization of ferromagnetic skyrmions in zero external magnetic fields, in exchange-biased systems composed of ferromagnetic-antiferromagnetic (FM-AFM) bilayers. By performing atomistic spin dynamics simulations, we study cases of compensated, uncompensated, and partly uncompensated FM-AFM interfaces, and investigate the impact of important parameters such as temperature, inter-plane exchange interaction, Dzyaloshinskii-Moriya interaction, and magnetic anisotropy on the skyrmions appearance and stability. The model with an uncompensated FM-AFM interface leads to the stabilization of individual skyrmions and skyrmion lattices in the FM layer, caused by the effective field from the AFM instead of an external magnetic field. Similarly, in the case of a fully compensated FM-AFM interface, we show that FM skyrmions can be stabilized. We also demonstrate that accounting for interface roughness leads to stabilization of skyrmions both in compensated and uncompensated interface. Moreover, in bilayers with a rough interface, skyrmions in the FM layer are observed for a wide range of exchange interaction values through the FM-AFM interface, and the chirality of the skyrmions depends critically on the exchange interaction.
Collapse
Affiliation(s)
- M Pankratova
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-75120 Uppsala, Sweden
- Wallenberg Initiative Materials Science for Sustainability, Uppsala University, 75121 Uppsala, Sweden
| | - O Eriksson
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-75120 Uppsala, Sweden
- Wallenberg Initiative Materials Science for Sustainability, Uppsala University, 75121 Uppsala, Sweden
| | - A Bergman
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-75120 Uppsala, Sweden
| |
Collapse
|
30
|
Yang B, Patel T, Cheng M, Pichugin K, Tian L, Sherlekar N, Yan S, Fu Y, Tian S, Lei H, Reimer ME, Okamoto J, Tsen AW. Macroscopic tunneling probe of Moiré spin textures in twisted CrI 3. Nat Commun 2024; 15:4982. [PMID: 38862504 PMCID: PMC11167019 DOI: 10.1038/s41467-024-49261-6] [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: 05/07/2024] [Accepted: 05/30/2024] [Indexed: 06/13/2024] Open
Abstract
Various noncollinear spin textures and magnetic phases have been predicted in twisted two-dimensional CrI3 due to competing ferromagnetic (FM) and antiferromagnetic (AFM) interlayer exchange from moiré stacking-with potential spintronic applications even when the underlying material possesses a negligible Dzyaloshinskii-Moriya or dipole-dipole interaction. Recent measurements have shown evidence of coexisting FM and AFM layer order in small-twist-angle CrI3 bilayers and double bilayers. Yet, the nature of the magnetic textures remains unresolved and possibilities for their manipulation and electrical readout are unexplored. Here, we use tunneling magnetoresistance to investigate the collective spin states of twisted double-bilayer CrI3 under both out-of-plane and in-plane magnetic fields together with detailed micromagnetic simulations of domain dynamics based on magnetic circular dichroism. Our results capture hysteretic and anisotropic field evolutions of the magnetic states and we further uncover two distinct non-volatile spin textures (out-of-plane and in-plane domains) at ≈1° twist angle, with a different global tunneling resistance that can be switched by magnetic field.
Collapse
Affiliation(s)
- Bowen Yang
- Institute for Quantum Computing, University of Waterloo, Waterloo, ON, Canada
- Department of Physics and Astronomy, University of Waterloo, Waterloo, ON, Canada
| | - Tarun Patel
- Institute for Quantum Computing, University of Waterloo, Waterloo, ON, Canada
- Department of Physics and Astronomy, University of Waterloo, Waterloo, ON, Canada
| | - Meixin Cheng
- Institute for Quantum Computing, University of Waterloo, Waterloo, ON, Canada
- Department of Chemistry, University of Waterloo, Waterloo, ON, Canada
| | | | - Lin Tian
- Institute for Quantum Computing, University of Waterloo, Waterloo, ON, Canada
- Department of Electrical and Computer Engineering, University of Waterloo, Waterloo, Canada
| | - Nachiket Sherlekar
- Institute for Quantum Computing, University of Waterloo, Waterloo, ON, Canada
- Department of Physics and Astronomy, University of Waterloo, Waterloo, ON, Canada
| | - Shaohua Yan
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-nano Devices, Renmin University of China, Beijing, China
| | - Yang Fu
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-nano Devices, Renmin University of China, Beijing, China
| | - Shangjie Tian
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-nano Devices, Renmin University of China, Beijing, China
- School of Materials Science and Engineering, Anhui University, Hefei, China
| | - Hechang Lei
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-nano Devices, Renmin University of China, Beijing, China
| | - Michael E Reimer
- Institute for Quantum Computing, University of Waterloo, Waterloo, ON, Canada
- Department of Electrical and Computer Engineering, University of Waterloo, Waterloo, Canada
| | - Junichi Okamoto
- Institute of Physics, University of Freiburg, Freiburg, Germany
- EUCOR Centre for Quantum Science and Quantum Computing, University of Freiburg, Freiburg, Germany
| | - Adam W Tsen
- Institute for Quantum Computing, University of Waterloo, Waterloo, ON, Canada.
- Department of Chemistry, University of Waterloo, Waterloo, ON, Canada.
| |
Collapse
|
31
|
Zhou Y, Li S, Liang X, Zhou Y. Topological Spin Textures: Basic Physics and Devices. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024:e2312935. [PMID: 38861696 DOI: 10.1002/adma.202312935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 05/24/2024] [Indexed: 06/13/2024]
Abstract
In the face of escalating modern data storage demands and the constraints of Moore's Law, exploring spintronic solutions, particularly the devices based on magnetic skyrmions, has emerged as a promising frontier in scientific research. Since the first experimental observation of skyrmions, topological spin textures have been extensively studied for their great potential as efficient information carriers in spintronic devices. However, significant challenges have emerged alongside this progress. This review aims to synthesize recent advances in skyrmion research while addressing the major issues encountered in the field. Additionally, current research on promising topological spin structures in addition to skyrmions is summarized. Beyond 2D structures, exploration also extends to 1D magnetic solitons and 3D spin textures. In addition, a diverse array of emerging magnetic materials is introduced, including antiferromagnets and 2D van der Waals magnets, broadening the scope of potential materials hosting topological spin textures. Through a systematic examination of magnetic principles, topological categorization, and the dynamics of spin textures, a comprehensive overview of experimental and theoretical advances in the research of topological magnetism is provided. Finally, both conventional and unconventional applications are summarized based on spin textures proposed thus far. This review provides an outlook on future development in applied spintronics.
Collapse
Affiliation(s)
- Yuqing Zhou
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, Guangdong, 518172, China
| | - Shuang Li
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, Guangdong, 518172, China
| | - Xue Liang
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, Guangdong, 518172, China
| | - Yan Zhou
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, Guangdong, 518172, China
| |
Collapse
|
32
|
Ran K, Tan W, Sun X, Liu Y, Dalgliesh RM, Steinke NJ, van der Laan G, Langridge S, Hesjedal T, Zhang S. Bending skyrmion strings under two-dimensional thermal gradients. Nat Commun 2024; 15:4860. [PMID: 38849412 PMCID: PMC11161597 DOI: 10.1038/s41467-024-49288-9] [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: 09/30/2023] [Accepted: 05/31/2024] [Indexed: 06/09/2024] Open
Abstract
Magnetic skyrmions are topologically protected magnetization vortices that form three-dimensional strings in chiral magnets. With the manipulation of skyrmions being key to their application in devices, the focus has been on their dynamics within the vortex plane, while the dynamical control of skyrmion strings remained uncharted territory. Here, we report the effective bending of three-dimensional skyrmion strings in the chiral magnet MnSi in orthogonal thermal gradients using small angle neutron scattering. This dynamical behavior is achieved by exploiting the temperature-dependent skyrmion Hall effect, which is unexpected in the framework of skyrmion dynamics. We thus provide experimental evidence for the existence of magnon friction, which was recently proposed to be a key ingredient for capturing skyrmion dynamics, requiring a modification of Thiele's equation. Our work therefore suggests the existence of an extra degree of freedom for the manipulation of three-dimensional skyrmions.
Collapse
Affiliation(s)
- Kejing Ran
- School of Physical Science and Technology and ShanghaiTech Laboratory for Topological Physics, ShanghaiTech University, Shanghai, China
- College of Physics & Center of Quantum Materials and Devices, Chongqing University, Chongqing, China
| | - Wancong Tan
- School of Physical Science and Technology and ShanghaiTech Laboratory for Topological Physics, ShanghaiTech University, Shanghai, China
| | - Xinyu Sun
- School of Physical Science and Technology and ShanghaiTech Laboratory for Topological Physics, ShanghaiTech University, Shanghai, China
| | - Yizhou Liu
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Japan
| | | | | | | | | | - Thorsten Hesjedal
- Department of Physics, Clarendon Laboratory, University of Oxford, Oxford, UK
| | - Shilei Zhang
- School of Physical Science and Technology and ShanghaiTech Laboratory for Topological Physics, ShanghaiTech University, Shanghai, China.
| |
Collapse
|
33
|
Adorjáni B, Libál A, Reichhardt C, Reichhardt CJO. Phase separation, edge currents, and Hall effect for active matter with Magnus dynamics. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2024; 47:40. [PMID: 38844720 DOI: 10.1140/epje/s10189-024-00431-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 05/06/2024] [Indexed: 07/11/2024]
Abstract
We examine run-and-tumble disks in two-dimensional systems where the particles also have a Magnus component to their dynamics. For increased activity, we find that the system forms a motility-induced phase-separated (MIPS) state with chiral edge flow around the clusters, where the direction of the current is correlated with the sign of the Magnus term. The stability of the MIPS state is non-monotonic as a function of increasing Magnus term amplitude, with the MIPS region first extending down to lower activities followed by a break up of MIPS at large Magnus amplitudes into a gel-like state. We examine the dynamics in the presence of quenched disorder and a uniform drive and find that the bulk flow exhibits a drive-dependent Hall angle. This is a result of the side jump effect produced by scattering from the pinning sites and is similar to the behavior found for skyrmions in chiral magnets with quenched disorder.
Collapse
Affiliation(s)
- B Adorjáni
- Mathematics and Computer Science Department, Babeş-Bolyai University, 400084, Cluj, Romania
| | - A Libál
- Mathematics and Computer Science Department, Babeş-Bolyai University, 400084, Cluj, Romania
| | - C Reichhardt
- Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - C J O Reichhardt
- Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA.
| |
Collapse
|
34
|
Littlehales MT, Moody SH, Turnbull LA, Huddart BM, Brereton BA, Balakrishnan G, Fan R, Steadman P, Hatton PD, Wilson MN. Demonstration of Controlled Skyrmion Injection Across a Thickness Step. NANO LETTERS 2024; 24:6813-6820. [PMID: 38781191 PMCID: PMC11157652 DOI: 10.1021/acs.nanolett.4c01605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2024] [Revised: 05/17/2024] [Accepted: 05/17/2024] [Indexed: 05/25/2024]
Abstract
Spintronic devices incorporating magnetic skyrmions have attracted significant interest recently. Such devices traditionally focus on controlling magnetic textures in 2D thin films. However, enhanced performance of spintronic properties through the exploitation of higher dimensionalities motivates the investigation of variable-thickness skyrmion devices. We report the demonstration of a skyrmion injection mechanism that utilizes charge currents to drive skyrmions across a thickness step and, consequently, a metastability barrier. Our measurements show that under certain temperature and field conditions skyrmions can be reversibly injected from a thin region of an FeGe lamella, where they exist as an equilibrium state, into a thicker region, where they can only persist as a metastable state. This injection is achieved with a current density of 3 × 108 A m-2, nearly 3 orders of magnitude lower than required to move magnetic domain walls. This highlights the possibility to use such an element as a skyrmion source/drain within future spintronic devices.
Collapse
Affiliation(s)
- Matthew T. Littlehales
- Durham
University, Department of Physics, South Road, Durham, DH1 3LE, United Kingdom
- ISIS
Neutron and Muon Source, Rutherford Appleton
Laboratory, Didcot, OX11 0QX, United Kingdom
| | - Samuel H. Moody
- Durham
University, Department of Physics, South Road, Durham, DH1 3LE, United Kingdom
- Laboratory
for Neutron Scattering and Imaging, Paul
Scherrer Institute, Villigen, CH-5232, Switzerland
| | - Luke A. Turnbull
- Durham
University, Department of Physics, South Road, Durham, DH1 3LE, United Kingdom
- Max
Planck Institute for Chemical Physics of Solids, Noethnitzer Str. 40, 01187 Dresden, Germany
| | - Benjamin M. Huddart
- Durham
University, Department of Physics, South Road, Durham, DH1 3LE, United Kingdom
- Department
of Physics, Clarendon Laboratory, University
of Oxford, Parks Road, Oxford, OX1
3PU, United Kingdom
| | - Ben A. Brereton
- Durham
University, Department of Physics, South Road, Durham, DH1 3LE, United Kingdom
| | - Geetha Balakrishnan
- University
of Warwick, Department of Physics, Coventry, CV4 7AL, United Kingdom
| | - Raymond Fan
- Diamond
Light Source, Didcot, OX11 0DE, United
Kingdom
| | - Paul Steadman
- Diamond
Light Source, Didcot, OX11 0DE, United
Kingdom
| | - Peter D. Hatton
- Durham
University, Department of Physics, South Road, Durham, DH1 3LE, United Kingdom
| | - Murray N. Wilson
- Durham
University, Department of Physics, South Road, Durham, DH1 3LE, United Kingdom
- Memorial
University of Newfoundland, Department of Physics and Physical Oceanography, St John’s, Newfoundland, A1B 3X7, Canada
| |
Collapse
|
35
|
Lee J, Park HR, Jin KH, Kim JS, Cheong SW, Yeom HW. Topological Complex Charge Conservation in Nontrivial Z 2 × Z 2 Domain Walls. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2313803. [PMID: 38482920 DOI: 10.1002/adma.202313803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Revised: 02/14/2024] [Indexed: 03/22/2024]
Abstract
Localized topological modes such as solitons, Majorana Fermions, and skyrmions are attracting great interest as robust information carriers for future devices. Here, a novel conserved quantity for topological domain wall networks of a Z2 × Z2 order generated with spin-polarized current in Sr2VO3FeAs is discovered. Domain walls are mobilized by the scanning tunneling current, which also observes in atomic scale active dynamics of domain wall vertices including merge, bifurcation, pair creation, and annihilation. Within this dynamics, the product of the topological complex charges defined for domain wall vertices is conserved with a novel boundary-charge correspondence rule. These results may open an avenue toward topological electronics based on domain wall vertices in generic Z2 × Z2 systems.
Collapse
Affiliation(s)
- Jhinhwan Lee
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
| | - Hae-Ryong Park
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Kyung-Hwan Jin
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
| | - Jun Sung Kim
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Sang-Wook Cheong
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, 08854, USA
| | - Han-Woong Yeom
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| |
Collapse
|
36
|
Saavedra E, Tejo F, Vidal-Silva N, Escrig J. Symmetry Breaking-Induced Resonance Dynamics in Bloch Point Nanospheres: Unveiling Magnetic Volume Effects and Geometric Parameters for Advanced Applications in Magnetic Sensing and Spintronics. ACS APPLIED MATERIALS & INTERFACES 2024; 16:27605-27613. [PMID: 38754391 DOI: 10.1021/acsami.4c01963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2024]
Abstract
This study explores the impact of symmetry breaking on the ferromagnetic resonance of Bloch point (BP) nanospheres. Through standard Fourier analysis, we unveil two distinct oscillation mode groups characterized by low and high frequencies, respectively. Our findings emphasize the pivotal role of magnetic volume in shaping resonance amplitudes, providing new insights into the intricate dynamics of BP states. The investigation of geometric parameters reveals a quasi-monotonic decrease in resonance frequencies as a function of the asymmetry degree attributed to symmetry-breaking induced by geometric modifications. Spatial distribution analysis showcases unique resonance frequencies for the upper and lower BP hemispheres, highlighting the nuanced impact of the geometry on mode excitation. As the radius increases, additional modes emerge, demonstrating a compelling relationship between the magnetic volume and frequency. Phase analysis unveils coherent oscillations within each BP hemisphere, offering valuable insights into the rotational directions of the excitation poles. Beyond fundamental understanding, our study opens avenues for innovative applications, suggesting the potential use of nanospheres in advanced magnetic sensing, data storage, and nanoscale spintronic devices.
Collapse
Affiliation(s)
- Eduardo Saavedra
- Departamento de Física, Universidad de Santiago de Chile, Santiago 9170124, Chile
| | - Felipe Tejo
- Escuela de Ingenieria, Universidad Central de Chile, Santiago 8330601, Chile
| | - Nicolas Vidal-Silva
- Departamento de Ciencias Físicas, Universidad de La Frontera, Temuco 4811186, Chile
| | - Juan Escrig
- Departamento de Física, Universidad de Santiago de Chile, Santiago 9170124, Chile
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), Santiago 9170124, Chile
| |
Collapse
|
37
|
Thomsen JD, Han MG, Penn AN, Foucher AC, Geiwitz M, Burch KS, Dekanovsky L, Sofer Z, Liu Y, Petrovic C, Ross FM, Zhu Y, Narang P. Effect of Surface Oxidation and Crystal Thickness on the Magnetic Properties and Magnetic Domain Structures of Cr 2Ge 2Te 6. ACS NANO 2024; 18:13458-13467. [PMID: 38739873 DOI: 10.1021/acsnano.3c09858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
van der Waals (vdW) magnetic materials, such as Cr2Ge2Te6 (CGT), show promise for memory and logic applications. This is due to their broadly tunable magnetic properties and the presence of topological magnetic features such as skyrmionic bubbles. A systematic study of thickness and oxidation effects on magnetic domain structures is important for designing devices and vdW heterostructures for practical applications. Here, we investigate thickness effects on magnetic properties, magnetic domains, and bubbles in oxidation-controlled CGT crystals. We find that CGT exposed to ambient conditions for 5 days forms an oxide layer approximately 5 nm thick. This oxidation leads to a significant increase in the oxidation state of the Cr ions, indicating a change in local magnetic properties. This is supported by real-space magnetic texture imaging through Lorentz transmission electron microscopy. By comparing the thickness-dependent saturation field of oxidized and pristine crystals, we find that oxidation leads to a nonmagnetic surface layer that is thicker than the oxide layer alone. We also find that the stripe domain width and skyrmionic bubble size are strongly affected by the crystal thickness in pristine crystals. These findings underscore the impact of thickness and surface oxidation on the properties of CGT, such as saturation field and domain/skyrmionic bubble size, and suggest a pathway for manipulating magnetic properties through a controlled oxidation process.
Collapse
Affiliation(s)
- Joachim Dahl Thomsen
- Division of Physical Sciences, College of Letters and Science, University of California, Los Angeles, Los Angeles, California 90095, United States
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Myung-Geun Han
- Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Aubrey N Penn
- MIT.nano, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Alexandre C Foucher
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Michael Geiwitz
- Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Kenneth Stephen Burch
- Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Lukas Dekanovsky
- Department of Inorganic Chemistry, University of Chemistry and Technology Prague, Technická 5, Prague 6 166 28, Czech Republic
| | - Zdeněk Sofer
- Department of Inorganic Chemistry, University of Chemistry and Technology Prague, Technická 5, Prague 6 166 28, Czech Republic
| | - Yu Liu
- Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Upton, New York 11973, United States
- Center for Correlated Matter and School of Physics, Zhejiang University, Hangzhou 310058, People's Republic of China
| | - Cedomir Petrovic
- Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Upton, New York 11973, United States
- Shanghai Key Laboratory of Material Frontiers Research in Extreme Environments (MFree), Shanghai Advanced Research in Physical Sciences (SHARPS), Pudong, Shanghai 201203, People's Republic of China
| | - Frances M Ross
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Yimei Zhu
- Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Prineha Narang
- Division of Physical Sciences, College of Letters and Science, University of California, Los Angeles, Los Angeles, California 90095, United States
- Electrical and Computer Engineering Department, University of California, Los Angeles, Los Angeles, California 90095, United States
| |
Collapse
|
38
|
Kazemi M, Kudlis A, Bessarab PF, Shelykh IA. All-optical control of skyrmion configuration in CrI 3 monolayer. Sci Rep 2024; 14:11677. [PMID: 38778124 PMCID: PMC11111699 DOI: 10.1038/s41598-024-62175-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: 03/05/2024] [Accepted: 05/14/2024] [Indexed: 05/25/2024] Open
Abstract
The potential for manipulating characteristics of skyrmions in a CrI3 monolayer using circularly polarised light is explored. The effective skyrmion-light interaction is mediated by bright excitons whose magnetization is selectively influenced by the polarization of photons. The light-induced skyrmion dynamics is illustrated by the dependencies of the skyrmion size and the skyrmion lifetime on the intensity and polarization of the incident light pulse. Two-dimensional magnets hosting excitons thus represent a promising platform for the control of topological magnetic structures by light.
Collapse
Affiliation(s)
- M Kazemi
- Science Institute, University of Iceland, Dunhagi-3, IS-107, Reykjavík, Iceland.
| | - A Kudlis
- Science Institute, University of Iceland, Dunhagi-3, IS-107, Reykjavík, Iceland
- Abrikosov Center for Theoretical Physics, MIPT, Dolgoprudnyi, Moscow Region, Russia, 141701
- Russian Quantum Center, Skolkovo, Moscow, Russia, 121205
| | - P F Bessarab
- Science Institute, University of Iceland, Dunhagi-3, IS-107, Reykjavík, Iceland
- Department of Physics and Electrical Engineering, Linnaeus University, SE-39231, Kalmar, Sweden
| | - I A Shelykh
- Science Institute, University of Iceland, Dunhagi-3, IS-107, Reykjavík, Iceland
- Russian Quantum Center, Skolkovo, Moscow, Russia, 121205
| |
Collapse
|
39
|
Lafuente-Bartolome J, Lian C, Giustino F. Topological polarons in halide perovskites. Proc Natl Acad Sci U S A 2024; 121:e2318151121. [PMID: 38758696 PMCID: PMC11127022 DOI: 10.1073/pnas.2318151121] [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: 10/18/2023] [Accepted: 03/29/2024] [Indexed: 05/19/2024] Open
Abstract
Halide perovskites emerged as a revolutionary family of high-quality semiconductors for solar energy harvesting and energy-efficient lighting. There is mounting evidence that the exceptional optoelectronic properties of these materials could stem from unconventional electron-phonon couplings, and it has been suggested that the formation of polarons and self-trapped excitons could be key to understanding such properties. By performing first-principles simulations across the length scales, here we show that halide perovskites harbor a uniquely rich variety of polaronic species, including small polarons, large polarons, and charge density waves, and we explain a variety of experimental observations. We find that these emergent quasiparticles support topologically nontrivial phonon fields with quantized topological charge, making them nonmagnetic analog of the helical Bloch points found in magnetic skyrmion lattices.
Collapse
Affiliation(s)
- Jon Lafuente-Bartolome
- Oden Institute for Computational Engineering and Sciences, The University of Texas at Austin, Austin, TX78712
- Department of Physics, The University of Texas at Austin, Austin, TX78712
| | - Chao Lian
- Oden Institute for Computational Engineering and Sciences, The University of Texas at Austin, Austin, TX78712
- Department of Physics, The University of Texas at Austin, Austin, TX78712
| | - Feliciano Giustino
- Oden Institute for Computational Engineering and Sciences, The University of Texas at Austin, Austin, TX78712
- Department of Physics, The University of Texas at Austin, Austin, TX78712
| |
Collapse
|
40
|
Kitaori A, White JS, Ukleev V, Peng L, Nakajima K, Kanazawa N, Yu X, Ōnuki Y, Tokura Y. Enhanced emergent electromagnetic inductance in Tb 5Sb 3 due to highly disordered helimagnetism. COMMUNICATIONS PHYSICS 2024; 7:159. [PMID: 38779470 PMCID: PMC11106002 DOI: 10.1038/s42005-024-01656-z] [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: 12/23/2023] [Accepted: 05/08/2024] [Indexed: 05/25/2024]
Abstract
In helimagnetic metals, ac current-driven spin motions can generate emergent electric fields acting on conduction electrons, leading to emergent electromagnetic induction (EEMI). Recent experiments reveal the EEMI signal generally shows a strongly current-nonlinear response. In this study, we investigate the EEMI of Tb5Sb3, a short-period helimagnet. Using small angle neutron scattering we show that Tb5Sb3 hosts highly disordered helimagnetism with a distribution of spin-helix periodicity. The current-nonlinear dynamics of the disordered spin helix in Tb5Sb3 indeed shows up as the nonlinear electrical resistivity (real part of ac resistivity), and even more clearly as a nonlinear and huge EEMI (imaginary part of ac resistivity) response. The magnitude of the EEMI reaches as large as several tens of μH for Tb5Sb3 devices on the scale of several tens of μm, originating to noncollinear spin textures possibly even without long-range helimagnetic order.
Collapse
Affiliation(s)
- Aki Kitaori
- Institute of Engineering Innovation, The University of Tokyo, Tokyo, 113-0032 Japan
- Department of Applied Physics, The University of Tokyo, Tokyo, 113-8656 Japan
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198 Japan
| | - Jonathan S. White
- Laboratory for Neutron Scattering and Imaging (LNS), Paul Scherrer Institute (PSI), CH-5232 Villigen, Switzerland
| | - Victor Ukleev
- Laboratory for Neutron Scattering and Imaging (LNS), Paul Scherrer Institute (PSI), CH-5232 Villigen, Switzerland
- Helmholtz-Zentrum Berlin für Materialien und Energie, D-14109 Berlin, Germany
| | - Licong Peng
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198 Japan
| | - Kiyomi Nakajima
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198 Japan
| | - Naoya Kanazawa
- Institute of Industrial Science, The University of Tokyo, Tokyo, 153-8505 Japan
| | - Xiuzhen Yu
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198 Japan
| | - Yoshichika Ōnuki
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198 Japan
| | - Yoshinori Tokura
- Department of Applied Physics, The University of Tokyo, Tokyo, 113-8656 Japan
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198 Japan
- Tokyo College, The University of Tokyo, Tokyo, 113-8656 Japan
| |
Collapse
|
41
|
Jeong C, Lee J, Jo H, Oh J, Baik H, Go KJ, Son J, Choi SY, Prosandeev S, Bellaiche L, Yang Y. Revealing the three-dimensional arrangement of polar topology in nanoparticles. Nat Commun 2024; 15:3887. [PMID: 38719801 PMCID: PMC11078976 DOI: 10.1038/s41467-024-48082-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Accepted: 04/16/2024] [Indexed: 05/12/2024] Open
Abstract
In the early 2000s, low dimensional ferroelectric systems were predicted to have topologically nontrivial polar structures, such as vortices or skyrmions, depending on mechanical or electrical boundary conditions. A few variants of these structures have been experimentally observed in thin film model systems, where they are engineered by balancing electrostatic charge and elastic distortion energies. However, the measurement and classification of topological textures for general ferroelectric nanostructures have remained elusive, as it requires mapping the local polarization at the atomic scale in three dimensions. Here we unveil topological polar structures in ferroelectric BaTiO3 nanoparticles via atomic electron tomography, which enables us to reconstruct the full three-dimensional arrangement of cation atoms at an individual atom level. Our three-dimensional polarization maps reveal clear topological orderings, along with evidence of size-dependent topological transitions from a single vortex structure to multiple vortices, consistent with theoretical predictions. The discovery of the predicted topological polar ordering in nanoscale ferroelectrics, independent of epitaxial strain, widens the research perspective and offers potential for practical applications utilizing contact-free switchable toroidal moments.
Collapse
Affiliation(s)
- Chaehwa Jeong
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Juhyeok Lee
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
- Energy Geosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Hyesung Jo
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Jaewhan Oh
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Hionsuck Baik
- Korea Basic Science Institute (KBSI), Seoul, 02841, Republic of Korea
| | - Kyoung-June Go
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Junwoo Son
- Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Seoul, 08826, Republic of Korea
| | - Si-Young Choi
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
- Center for Van der Waals Quantum Solids, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
| | - Sergey Prosandeev
- Smart Ferroic Materials Center (SFMC), Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, AR, 72701, USA
| | - Laurent Bellaiche
- Smart Ferroic Materials Center (SFMC), Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, AR, 72701, USA
| | - Yongsoo Yang
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.
- Graduate School of Semiconductor Technology, School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.
| |
Collapse
|
42
|
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
|
43
|
Liu C, Zhang S, Hao H, Algaidi H, Ma Y, Zhang XX. Magnetic Skyrmions above Room Temperature in a van der Waals Ferromagnet Fe 3GaTe 2. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2311022. [PMID: 38290153 DOI: 10.1002/adma.202311022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2023] [Revised: 01/11/2024] [Indexed: 02/01/2024]
Abstract
2D van der Waals (vdW) ferromagnetic crystals are a promising platform for innovative spintronic devices based on magnetic skyrmions, thanks to their high flexibility and atomic thickness stability. However, room-temperature skyrmion-hosting vdW materials are scarce, which poses a challenge for practical applications. In this study, a chemical vapor transport (CVT) approach is employed to synthesize Fe3GaTe2 crystals and room-temperature Néel skyrmions are observed in Fe3GaTe2 nanoflakes above 58 nm in thickness through in situ Lorentz transmission electron microscopy (L-TEM). Upon an optimized field cooling procedure, zero-field hexagonal skyrmion lattices are successfully generated in nanoflakes with an extended thickness range (30-180 nm). Significantly, these skyrmion lattices remain stable up to 355 K, setting a new record for the highest temperature at which skyrmions can be hosted. The research establishes Fe3GaTe2 as an emerging above-room-temperature skyrmion-hosting vdW material, holding great promise for future spintronics.
Collapse
Affiliation(s)
- Chen Liu
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Senfu Zhang
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
- Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou, 730000, China
| | - Hongyuan Hao
- Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou, 730000, China
| | - Hanin Algaidi
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Yinchang Ma
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Xi-Xiang Zhang
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| |
Collapse
|
44
|
Zhang Y, Tang J, Wu Y, Shi M, Xu X, Wang S, Tian M, Du H. Stable skyrmion bundles at room temperature and zero magnetic field in a chiral magnet. Nat Commun 2024; 15:3391. [PMID: 38649678 PMCID: PMC11035646 DOI: 10.1038/s41467-024-47730-6] [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: 11/20/2023] [Accepted: 04/10/2024] [Indexed: 04/25/2024] Open
Abstract
Topological spin textures are characterized by magnetic topological charges, Q, which govern their electromagnetic properties. Recent studies have achieved skyrmion bundles with arbitrary integer values of Q, opening possibilities for exploring topological spintronics based on Q. However, the realization of stable skyrmion bundles in chiral magnets at room temperature and zero magnetic field - the prerequisite for realistic device applications - has remained elusive. Here, through the combination of pulsed currents and reversed magnetic fields, we experimentally achieve skyrmion bundles with different integer Q values - reaching a maximum of 24 at above room temperature and zero magnetic field - in the chiral magnet Co8Zn10Mn2. We demonstrate the field-driven annihilation of high-Q bundles and present a phase diagram as a function of temperature and field. Our experimental findings are consistently corroborated by micromagnetic simulations, which reveal the nature of the skyrmion bundle as that of skyrmion tubes encircled by a fractional Hopfion.
Collapse
Grants
- This work was supported by the National Key R&D Program of China, Grant No. 2022YFA1403603 (H.D.); the Natural Science Foundation of China, Grants No. 12174396 (J.T.), 12104123 (Y.W.), and 12241406 (H.D.); the National Natural Science Funds for Distinguished Young Scholar, Grant No. 52325105 (H.D.); the Anhui Provincial Natural Science Foundation, Grant No. 2308085Y32 (J.T.); the Natural Science Project of Colleges and Universities in Anhui Province, Grant No. 2022AH030011 (J.T.); the Strategic Priority Research Program of Chinese Academy of Sciences, Grant No. XDB33030100 (H.D.); CAS Project for Young Scientists in Basic Research, Grant No. YSBR-084 (H.D.); Systematic Fundamental Research Program Leveraging Major Scientific and Technological Infrastructure, Chinese Academy of Sciences, Grant No. JZHKYPT-2021-08 (H.D.);Anhui Province Excellent Young Teacher Training Project Grant No. YQZD2023067 (Y.W.); and the China Postdoctoral Science Foundation Grant No. 2023M743543 (Y.W.).
Collapse
Affiliation(s)
- Yongsen Zhang
- Science Island Branch, Graduate School of USTC, Hefei, 230026, China
- Anhui Province Key Laboratory of Low-Energy Quantum Materials and Devices, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences, Hefei, 230031, China
| | - Jin Tang
- School of Physics and Optoelectronic Engineering, Anhui University, Hefei, 230601, China.
| | - Yaodong Wu
- School of Physics and Materials Engineering, Hefei Normal University, Hefei, 230601, China
| | - Meng Shi
- Science Island Branch, Graduate School of USTC, Hefei, 230026, China
- Anhui Province Key Laboratory of Low-Energy Quantum Materials and Devices, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences, Hefei, 230031, China
| | - Xitong Xu
- Anhui Province Key Laboratory of Low-Energy Quantum Materials and Devices, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences, Hefei, 230031, China
| | - Shouguo Wang
- Anhui Key Laboratory of Magnetic Functional Materials and Devices, School of Materials Science and Engineering, Anhui University, Hefei, 230601, China
| | - Mingliang Tian
- Anhui Province Key Laboratory of Low-Energy Quantum Materials and Devices, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences, Hefei, 230031, China
- School of Physics and Optoelectronic Engineering, Anhui University, Hefei, 230601, China
| | - Haifeng Du
- Anhui Province Key Laboratory of Low-Energy Quantum Materials and Devices, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences, Hefei, 230031, China.
| |
Collapse
|
45
|
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
|
46
|
Yang S, Shen L, Zhao Y, Wu K, Li X, Shen K, Zhang S, Xu X, Åkerman J, Zhou Y. Generation of skyrmions by combining thermal and spin-orbit torque: breaking half skyrmions into skyrmions. NANOSCALE 2024; 16:7068-7075. [PMID: 38450557 DOI: 10.1039/d3nr05803d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/08/2024]
Abstract
Skyrmions, swirling spin textures with topologically protected stability and low critical driven-current density, can be generated from the stripe domain with current pulses, bringing them closer to practical applications in racetrack memory. However, the mechanism of this topological transition from the stripe domain to the skyrmion remains unclear because the transition process occurs at a nanosecond timescale, giving rise to difficulties in observing this process using imaging tools. In this study, we controlled the domain wall - skyrmion transition by combining Joule heating with spin-orbit torque (SOT) and experimentally observed the details of this process, by which we confirmed the mechanism: the spatial variation of the topological charge density induces half skyrmions branching from the stripe domains, and these half skyrmions overcome the surface tension and break away from the stripe domain, resulting in the generation of skyrmions. The details were observed by employing Joule heating to overcome the pinning effect and manipulating the strength of the SOT to induce the branching and breaking of half skyrmions. These findings offer new insights into skyrmion generation and serve as an important step towards the development of highly efficient devices for processing and computing based on skyrmionics.
Collapse
Affiliation(s)
- Sheng Yang
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, 518172, China.
| | - Laichuan Shen
- The Center for Advanced Quantum Studies and Department of Physics, Beijing Normal University, Beijing, 100875, China
- Key Laboratory of Multi-scale Spin Physics, Ministry of Education, Beijing Normal University, Beijing, 100875, China
| | - Yuelei Zhao
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, 518172, China.
| | - Kai Wu
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, 518172, China.
| | - Xiaoguang Li
- Center for Advanced Material Diagnostic Technology, College of Engineering Physics, Shenzhen Technology University, Shenzhen, 518118, China
| | - Ka Shen
- The Center for Advanced Quantum Studies and Department of Physics, Beijing Normal University, Beijing, 100875, China
- Key Laboratory of Multi-scale Spin Physics, Ministry of Education, Beijing Normal University, Beijing, 100875, China
| | - Senfu Zhang
- Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou, 730000, China
| | - Xiaohong Xu
- School of Chemistry and Materials Science of Shanxi Normal University & Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education, Taiyuan, 030006, China
- Research Institute of Materials Science of Shanxi Normal University & Collaborative Innovation Center for Shanxi Advanced Permanent Magnetic Materials and Technology, Taiyuan, 030006, China
| | - Johan Åkerman
- Department of Physics, University of Gothenburg, Gothenburg, 41296, Sweden
- Science and Innovation in Spintronics Research Institute of Electrical Communication, Tohoku University, Aoba-ku, 980-8577, Japan
| | - Yan Zhou
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, 518172, China.
| |
Collapse
|
47
|
Yasin FS, Masell J, Takahashi Y, Akashi T, Baba N, Karube K, Shindo D, Arima T, Taguchi Y, Tokura Y, Tanigaki T, Yu X. Bloch Point Quadrupole Constituting Hybrid Topological Strings Revealed with Electron Holographic Vector Field Tomography. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2311737. [PMID: 38219021 DOI: 10.1002/adma.202311737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 12/22/2023] [Indexed: 01/15/2024]
Abstract
Topological magnetic (anti)skyrmions are robust string-like objects heralded as potential components in next-generation topological spintronics devices due to their low-energy manipulability via stimuli such as magnetic fields, heat, and electric/thermal current. While these 2D topological objects are widely studied, intrinsically 3D electron-spin real-space topology remains less explored despite its prevalence in bulky magnets. 2D-imaging studies reveal peculiar vortex-like contrast in the core regions of spin textures present in antiskyrmion-hosting thin plate magnets with S4 crystal symmetry, suggesting a more complex 3D real-space structure than the 2D model suggests. Here, holographic vector field electron tomography captures the 3D structure of antiskyrmions in a single-crystal, precision-doped (Fe0.63Ni0.3Pd0.07)3P (FNPP) lamellae at room temperature and zero field. These measurements reveal hybrid string-like solitons composed of skyrmions with topological number W = -1 on the lamellae's surfaces and an antiskyrmion (W = + 1) connecting them. High-resolution images uncover a Bloch point quadrupole (four magnetic (anti)monopoles that are undetectable in 2D imaging) which enables the observed lengthwise topological transitions. Numerical calculations corroborate the stability of hybrid strings over their conventional (anti)skyrmion counterparts. Hybrid strings result in topological tuning, a tunable topological Hall effect, and the suppression of skyrmion Hall motion, disrupting existing paradigms within spintronics.
Collapse
Affiliation(s)
- Fehmi Sami Yasin
- RIKEN Center for Emergent Matter Science (CEMS), RIKEN, Wako, 351-0198, Japan
| | - Jan Masell
- RIKEN Center for Emergent Matter Science (CEMS), RIKEN, Wako, 351-0198, Japan
- Institute of Theoretical Solid State Physics, Karlsruhe Institute of Technology (KIT), 76049, Karlsruhe, Germany
| | - Yoshio Takahashi
- Research and Development Group, Hitachi Ltd., Hatoyama, 350-0395, Japan
| | - Tetsuya Akashi
- Research and Development Group, Hitachi Ltd., Hatoyama, 350-0395, Japan
| | - Norio Baba
- Research Institute for Science and Technology, Kogakuin University, Hachioji, 192-0015, Japan
| | - Kosuke Karube
- RIKEN Center for Emergent Matter Science (CEMS), RIKEN, Wako, 351-0198, Japan
| | - Daisuke Shindo
- RIKEN Center for Emergent Matter Science (CEMS), RIKEN, Wako, 351-0198, Japan
| | - Takahisa Arima
- RIKEN Center for Emergent Matter Science (CEMS), RIKEN, Wako, 351-0198, Japan
- Department of Advanced Materials Science, University of Tokyo, Kashiwa, 277-8561, Japan
| | - Yasujiro Taguchi
- RIKEN Center for Emergent Matter Science (CEMS), RIKEN, Wako, 351-0198, Japan
| | - Yoshinori Tokura
- RIKEN Center for Emergent Matter Science (CEMS), RIKEN, Wako, 351-0198, Japan
- Department of Applied Physics, University of Tokyo, Tokyo, 113-8656, Japan
- Tokyo College, University of Tokyo, Tokyo, 113-8656, Japan
| | - Toshiaki Tanigaki
- Research and Development Group, Hitachi Ltd., Hatoyama, 350-0395, Japan
| | - Xiuzhen Yu
- RIKEN Center for Emergent Matter Science (CEMS), RIKEN, Wako, 351-0198, Japan
| |
Collapse
|
48
|
Aramberri H, Íñiguez-González J. Brownian Electric Bubble Quasiparticles. PHYSICAL REVIEW LETTERS 2024; 132:136801. [PMID: 38613274 DOI: 10.1103/physrevlett.132.136801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 02/27/2024] [Indexed: 04/14/2024]
Abstract
Recent works on electric bubbles (including the experimental demonstration of electric skyrmions) constitute a breakthrough akin to the discovery of magnetic skyrmions some 15 years ago. So far research has focused on obtaining and visualizing these objects, which often appear to be immobile (pinned) in experiments. Thus, critical aspects of magnetic skyrmions-e.g., their quasiparticle nature, Brownian motion-remain unexplored (unproven) for electric bubbles. Here we use predictive atomistic simulations to investigate the basic dynamical properties of these objects in pinning-free model systems. We show that it is possible to find regimes where the electric bubbles can present long lifetimes (∼ns) despite being relatively small (diameter <2 nm). Additionally, we find that they can display stochastic dynamics with large and highly tunable diffusion constants. We thus establish the quasiparticle nature of electric bubbles and put them forward for the physical effects and applications (e.g., in token-based probabilistic computing) considered for magnetic skyrmions.
Collapse
Affiliation(s)
- Hugo Aramberri
- Materials Research and Technology Department, Luxembourg Institute of Science and Technology (LIST), Avenue des Hauts-Fourneaux 5, L-4362 Esch/Alzette, Luxembourg
| | - Jorge Íñiguez-González
- Materials Research and Technology Department, Luxembourg Institute of Science and Technology (LIST), Avenue des Hauts-Fourneaux 5, L-4362 Esch/Alzette, Luxembourg
- Department of Physics and Materials Science, University of Luxembourg, Rue du Brill 41, L-4422 Belvaux, Luxembourg
| |
Collapse
|
49
|
Minami S, Ikeda Y, Shimada T. Spontaneous Atomic-Scale Polar Skyrmions and Merons on a SrTiO 3 (001) Surface: Defect Engineering for Emerging Topological Orders. NANO LETTERS 2024; 24:3686-3693. [PMID: 38451549 DOI: 10.1021/acs.nanolett.3c05112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/08/2024]
Abstract
The emergence of nontrivial topological order in condensed matter has been attracting a great deal of attention owing to its promising technological applications in novel functional nanodevices. In ferroelectrics, the realization of polar topological order at an ultimately small scale is extremely challenging due to the lack of chiral interaction and the critical size of the ferroelectricity. Here, we break through these limitations and demonstrate that the ultimate atomic-scale polar skyrmion and meron (∼2 nm) can be induced by engineering oxygen vacancies on the SrTiO3 (001) surface based on first-principles calculations. The paraelectric-to-antiferrodistortive phase transition leads to a novel topological transition from skyrmion to meron, indicating phase-topology correlations. We also discuss accumulating and driving polar skyrmions based on the oxygen divacancy model; these results and the recent discovery of defect engineering techniques suggest the possibility of arithmetic operations on topological numbers through the natural self-organization and diffusion features of oxygen vacancies.
Collapse
Affiliation(s)
- Susumu Minami
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
| | - Yoshitaka Ikeda
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
| | - Takahiro Shimada
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
| |
Collapse
|
50
|
Urrestarazu Larrañaga J, Sisodia N, Guedas R, Pham VT, Di Manici I, Masseboeuf A, Garello K, Disdier F, Fernandez B, Wintz S, Weigand M, Belmeguenai M, Pizzini S, Sousa RC, Buda-Prejbeanu LD, Gaudin G, Boulle O. Electrical Detection and Nucleation of a Magnetic Skyrmion in a Magnetic Tunnel Junction Observed via Operando Magnetic Microscopy. NANO LETTERS 2024; 24:3557-3565. [PMID: 38499397 DOI: 10.1021/acs.nanolett.4c00316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/20/2024]
Abstract
Magnetic skyrmions are topological spin textures which are envisioned as nanometer scale information carriers in magnetic memory and logic devices. The recent demonstrations of room temperature skyrmions and their current induced manipulation in ultrathin films were first steps toward the realization of such devices. However, important challenges remain regarding the electrical detection and the low-power nucleation of skyrmions, which are required for the read and write operations. Here, we demonstrate, using operando magnetic microscopy experiments, the electrical detection of a single magnetic skyrmion in a magnetic tunnel junction (MTJ) and its nucleation and annihilation by gate voltage via voltage control of magnetic anisotropy. The nucleated skyrmion can be manipulated by both gate voltages and external magnetic fields, leading to tunable intermediate resistance states. Our results unambiguously demonstrate the readout and voltage controlled write operations in a single MTJ device, which is a major milestone for low power skyrmion based technologies.
Collapse
Affiliation(s)
| | - Naveen Sisodia
- Univ. Grenoble Alpes, CNRS, CEA, Grenoble INP, SPINTEC, 38000 Grenoble, France
| | - Rodrigo Guedas
- Univ. Grenoble Alpes, CNRS, CEA, Grenoble INP, SPINTEC, 38000 Grenoble, France
| | - Van Tuong Pham
- Univ. Grenoble Alpes, CNRS, CEA, Grenoble INP, SPINTEC, 38000 Grenoble, France
- Univ. Grenoble Alpes, CNRS, Institut Néel, 38042 Grenoble, France
| | - Ilaria Di Manici
- Univ. Grenoble Alpes, CNRS, CEA, Grenoble INP, SPINTEC, 38000 Grenoble, France
| | - Aurélien Masseboeuf
- Univ. Grenoble Alpes, CNRS, CEA, Grenoble INP, SPINTEC, 38000 Grenoble, France
| | - Kevin Garello
- Univ. Grenoble Alpes, CNRS, CEA, Grenoble INP, SPINTEC, 38000 Grenoble, France
| | - Florian Disdier
- Univ. Grenoble Alpes, CNRS, CEA, Grenoble INP, SPINTEC, 38000 Grenoble, France
| | - Bruno Fernandez
- Univ. Grenoble Alpes, CNRS, Institut Néel, 38042 Grenoble, France
| | - Sebastian Wintz
- Max Planck Institute for Intelligent Systems, Heisenbergstraße 3, 70569 Stuttgart, Germany
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, D-14109 Berlin, Germany
| | - Markus Weigand
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, D-14109 Berlin, Germany
| | - Mohamed Belmeguenai
- LSPM (CNRS-UPR 3407), Université Paris 13, Sorbonne Paris Cité, 99 Avenue Jean-Baptiste Clément, 93430 Villetaneuse, France
| | - Stefania Pizzini
- Univ. Grenoble Alpes, CNRS, Institut Néel, 38042 Grenoble, France
| | - Ricardo C Sousa
- Univ. Grenoble Alpes, CNRS, CEA, Grenoble INP, SPINTEC, 38000 Grenoble, France
| | | | - Gilles Gaudin
- Univ. Grenoble Alpes, CNRS, CEA, Grenoble INP, SPINTEC, 38000 Grenoble, France
| | - Olivier Boulle
- Univ. Grenoble Alpes, CNRS, CEA, Grenoble INP, SPINTEC, 38000 Grenoble, France
| |
Collapse
|