第1回物理工学科教室談話会[Dr. Oleg Tretiakov・4/5(金)11時~]

講 師:Dr. Oleg Tretiakov
所 属:Associate Professor, School of Physics, University of New South Wales, Sydney, Australia
題 目:Topotronics with Magnetic Topological Materials
日 時:2024 年 4 月 5 日(金)11:00~
Date and Time: April 5, 2024 (Friday) 11:00-
場 所:工 6 号館 3 階セミナー室A(対面のみ)
Place :Seminar Room A, 3rd floor, Engineering Bldg. 6 (in-person only)

I discuss topological magnetic textures, such as skyrmions, half-skyrmions (merons), bimerons and their anti-particles, which constitute tiny whirls of magnetism. They are promising candidates as information carriers for next generation electronics (thus called topotronics), as they can be efficiently propelled at very high velocities employing current-induced spin torques [1]. First, I will talk about skyrmions [2,3] and bimerons [4,5] in ferromagnetic systems coupled to heavy metals and topological materials. Then I will show that antiferromagnets can also host a variety of these textures, which have gained significant attention because of their potential for terahertz dynamics, deflection free motion [6], and improved size scaling due to the absence of stray fields. Finally, I will demonstrate that topological spin textures, merons and antimerons, can be generated at room temperature and reversibly moved using electrical pulses in thin film CuMnAs, a semimetallic antiferromagnet that is a test-bed system for spintronic applications [7].

[1] B. Göbel, I. Mertig, and O.A.T., Phys. Rep. 895, 1 (2021); [2] D. Kurebayashi and O.A.T., Phys. Rev. Res. 4, 043105 (2022); [3] M.-G. Han, F. Camino, P. A. Vorobyev, J. Garlow, R. Rov, T. Söhnel, J. Seidel, M. Mostovoy, O.A.T., Y. Zhu, Nano Lett. 23, 7143 (2023); [4] B. Göbel, A. Mook, I. Mertig, and O.A.T., PRB 99, 060407(R) (2019); [5] K. Ohara, O.A.T. et al., Nano Lett. 22, 8559 (2022); [6] J. Barker and O.A.T., PRL 116, 147203 (2016); [7] O. J. Amin, O.A.T., et al., Nat. Nanotechnol. 18, 849 (2023).

紹介教員:Max Hirschberger 准教授(物理工学専攻)、求 幸年 教授(物理工学専攻)