The Hong Kong University of Science and Technology

Abstract:

Magnetization reversal of a single domain nano-particle by a spin-Hall/spin-orbit torque is discussed. We proposed to use two mutually perpendicular electric current components in a heavy-metal film to generate a total current whose direction can vary with time. The Euler-Lagrange equation of the optimal current pulse for the fastest magnetization reversal are found. The equation allows us to obtain the theoretical limit of the minimal magnetization reversal current. The theoretical limit of minimal reversal current is far below the value of the minimal magnetization reversal current of fixed current direction. Above the theoretical limit, the magnetization reversal time under the optimal pulse is very short. These results provide a benchmark for evaluating different strategies of spin-Hall/spin-orbit torque induced magnetization reversal.

Reference: Yin Zhang et al. Phys. Rev. B 97, 144416 (2018)

报告人简介：

王向荣， 1984年本科毕业于武汉大学物理系，同年通过中美联合招收物理研究生(CUSPEA) 赴美深造；1990年在美国罗彻斯特大学(University of Rochester)获博士学位，现为香港科技大学终身教授。主要从事凝聚态理论研究，目前关注重点是磁动力学，自旋电子学及拓扑系统中的电子和磁子性质。迄今已在国际权威学术杂志发表论文100余篇。

联系人：孙阳 研究员，82648080