[23a-A205-1~13] 10.2 スピン基盤技術・萌芽的デバイス技術

▲ [23a-A205-1] Current-induced bifurcation of a three-dimensional topological skyrmion string

〇(P)Jing XIA¹、X. Zhang¹、O. A. Tretiakov²、H. T. Diep³、J. Yang⁴、G. P. Zhao⁵、M. Ezawa⁶、Y. Zhou⁷、X. Liu¹ (1.Shinshu Univ.、2.UNSW Sydney、3.CY Cergy Paris Univ.、4.Peking Univ.、5.Sichuan Normal Univ.、6.Univ. of Tokyo、7.CUHKSZ)

キーワード：magnetic skyrmions

Nanoscale topological spin textures in magnetic materials are promising building blocks for future information storage and computing applications. The manipulation and control of two-dimensional and three-dimensional (3D) topological spin textures are prerequisite for the realization of spintronic devices based on topological spin textures. The manipulation of 3D topological objects is also of fundamental interest in many branches of physics. In this work, we show by spin dynamics simulations that the bifurcation of a 3D skyrmion string in a layered frustrated system could be induced by the damping-like spin-orbit torque. The bifurcation of a skyrmion string happens when the skyrmion string carries a minimal topological charge of Q = 2. We demonstrate that three types of bifurcations could be realized by applying different current injection geometries, which lead to the transformation from I-shaped skyrmion strings to Y-, X-, and O-shaped ones. Besides, different branches of a bifurcated skyrmion string may merge into an isolated skyrmion string spontaneously. The mechanism of bifurcation should be universal to any skyrmion strings with Q ≥ 2 in the layered frustrated system and could offer a general approach to manipulate 3D string-like topological objects for spintronic functions.