1
|
Bhukta M, Dohi T, Bharadwaj VK, Zarzuela R, Syskaki MA, Foerster M, Niño MA, Sinova J, Frömter R, Kläui M. Homochiral antiferromagnetic merons, antimerons and bimerons realized in synthetic antiferromagnets. Nat Commun 2024; 15:1641. [PMID: 38409221 PMCID: PMC10897388 DOI: 10.1038/s41467-024-45375-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 01/23/2024] [Indexed: 02/28/2024] Open
Abstract
The ever-growing demand for device miniaturization and energy efficiency in data storage and computing technology has prompted a shift towards antiferromagnetic topological spin textures as information carriers. This shift is primarily owing to their negligible stray fields, leading to higher possible device density and potentially ultrafast dynamics. We realize in this work such chiral in-plane topological antiferromagnetic spin textures namely merons, antimerons, and bimerons in synthetic antiferromagnets by concurrently engineering the effective perpendicular magnetic anisotropy, the interlayer exchange coupling, and the magnetic compensation ratio. We demonstrate multimodal vector imaging of the three-dimensional Néel order parameter, revealing the topology of those spin textures and a globally well-defined chirality, which is a crucial requirement for controlled current-induced dynamics. Our analysis reveals that the interplay between interlayer exchange and interlayer magnetic dipolar interactions plays a key role to significantly reduce the critical strength of the Dzyaloshinskii-Moriya interaction required to stabilize topological spin textures, such as antiferromagnetic merons, in synthetic antiferromagnets, making them a promising platform for next-generation spintronics applications.
Collapse
Affiliation(s)
- Mona Bhukta
- Institute of Physics, Johannes Gutenberg-University Mainz, 55099, Mainz, Germany
| | - Takaaki Dohi
- Institute of Physics, Johannes Gutenberg-University Mainz, 55099, Mainz, Germany.
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba, Sendai, 980-8577, Japan.
| | | | - Ricardo Zarzuela
- Institute of Physics, Johannes Gutenberg-University Mainz, 55099, Mainz, Germany
| | - Maria-Andromachi Syskaki
- Institute of Physics, Johannes Gutenberg-University Mainz, 55099, Mainz, Germany
- Singulus Technologies AG, Hanauer Landstrasse 107, 63796, Kahl am Main, Germany
| | - Michael Foerster
- ALBA Synchrotron Light Facility, 08290, Cerdanyola del Vallés, Barcelona, Spain
| | - Miguel Angel Niño
- ALBA Synchrotron Light Facility, 08290, Cerdanyola del Vallés, Barcelona, Spain
| | - Jairo Sinova
- Institute of Physics, Johannes Gutenberg-University Mainz, 55099, Mainz, Germany
| | - Robert Frömter
- Institute of Physics, Johannes Gutenberg-University Mainz, 55099, Mainz, Germany.
| | - Mathias Kläui
- Institute of Physics, Johannes Gutenberg-University Mainz, 55099, Mainz, Germany.
| |
Collapse
|
2
|
Darwin E, Tomasello R, Shepley PM, Satchell N, Carpentieri M, Finocchio G, Hickey BJ. Antiferromagnetic interlayer exchange coupled Co 68B 32/Ir/Pt multilayers. Sci Rep 2024; 14:95. [PMID: 38168577 PMCID: PMC10761723 DOI: 10.1038/s41598-023-49976-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 12/14/2023] [Indexed: 01/05/2024] Open
Abstract
Synthetic antiferromagnetic structures can exhibit the advantages of high velocity similarly to antiferromagnets with the additional benefit of being imaged and read-out through techniques applied to ferromagnets. Here, we explore the potential and limits of synthetic antiferromagnets to uncover ways to harness their valuable properties for applications. Two synthetic antiferromagnetic systems have been engineered and systematically investigated to provide an informed basis for creating devices with maximum potential for data storage, logic devices, and skyrmion racetrack memories. The two systems considered are (system 1) CoB/Ir/Pt of N repetitions with Ir inducing the negative coupling between the ferromagnetic layers and (system 2) two ferromagnetically coupled multilayers of CoB/Ir/Pt, coupled together antiferromagnetically with an Ir layer. From the hysteresis, it is found that system 1 shows stable antiferromagnetic interlayer exchange coupling between each magnetic layer up to N = 7. Using Kerr imaging, the two ferromagnetic multilayers in system 2 are shown to undergo separate maze-like switches during hysteresis. Both systems are also studied as a function of temperature and show different behaviors. Micromagnetic simulations predict that in both systems the skyrmion Hall angle is suppressed with the skyrmion velocity five times higher in system 1 than system 2.
Collapse
Affiliation(s)
- Emily Darwin
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
- Department of Electrical and Information Engineering, Politecnico Di Bari, Via E. Orabona 4, 70125, Bari, Italy
| | - Riccardo Tomasello
- Department of Electrical and Information Engineering, Politecnico Di Bari, Via E. Orabona 4, 70125, Bari, Italy
| | - Philippa M Shepley
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
| | - Nathan Satchell
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
- Department of Physics, Texas State University, San Marcos, TX, 78666, USA
| | - Mario Carpentieri
- Department of Electrical and Information Engineering, Politecnico Di Bari, Via E. Orabona 4, 70125, Bari, Italy
| | - Giovanni Finocchio
- Department of Mathematical and Computer Sciences, Physical Sciences and Earth Sciences, University of Messina, 98166, Messina, Italy.
| | - B J Hickey
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK.
| |
Collapse
|
3
|
Zhang X, Xia J, Tretiakov OA, Ezawa M, Zhao G, Zhou Y, Liu X, Mochizuki M. Chiral Skyrmions Interacting with Chiral Flowers. Nano Lett 2023; 23:11793-11801. [PMID: 38055779 PMCID: PMC10755743 DOI: 10.1021/acs.nanolett.3c03792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 12/02/2023] [Accepted: 12/04/2023] [Indexed: 12/08/2023]
Abstract
The chiral nature of active matter plays an important role in the dynamics of active matter interacting with chiral structures. Skyrmions are chiral objects, and their interactions with chiral nanostructures can lead to intriguing phenomena. Here, we explore the random-walk dynamics of a thermally activated chiral skyrmion interacting with a chiral flower-like obstacle in a ferromagnetic layer, which could create topology-dependent outcomes. It is a spontaneous mesoscopic order-from-disorder phenomenon driven by the thermal fluctuations and topological nature of skyrmions that exists only in ferromagnetic and ferrimagnetic systems. The interactions between the skyrmions and chiral flowers at finite temperatures can be utilized to control the skyrmion position and distribution without applying any external driving force or temperature gradient. The phenomenon that thermally activated skyrmions are dynamically coupled to chiral flowers may provide a new way to design topological sorting devices.
Collapse
Affiliation(s)
- Xichao Zhang
- Department
of Applied Physics, Waseda University, Okubo, Shinjuku-ku, Tokyo 169-8555, Japan
| | - Jing Xia
- Department
of Electrical and Computer Engineering, Shinshu University, 4-17-1 Wakasato, Nagano 380-8553, Japan
| | - Oleg A. Tretiakov
- School
of Physics, The University of New South
Wales, Sydney 2052, Australia
| | - Motohiko Ezawa
- Department
of Applied Physics, The University of Tokyo, 7-3-1 Hongo, Tokyo 113-8656, Japan
| | - Guoping Zhao
- College
of Physics and Electronic Engineering, Sichuan
Normal University, Chengdu 610068, China
| | - Yan Zhou
- School
of
Science and Engineering, The Chinese University
of Hong Kong, Shenzhen, Guangdong 518172, China
| | - Xiaoxi Liu
- Department
of Electrical and Computer Engineering, Shinshu University, 4-17-1 Wakasato, Nagano 380-8553, Japan
| | - Masahito Mochizuki
- Department
of Applied Physics, Waseda University, Okubo, Shinjuku-ku, Tokyo 169-8555, Japan
| |
Collapse
|