Controlling Spin Polarization Direction in Spin Orbit Torques

报告题目：Controlling Spin Polarization Direction in Spin Orbit Torques

报告人：Prof.John Q. Xiao   University of Delaware

报告时间：11月20日（周二）下午14:00-15:00

报告地点：物理科技楼101

报告邀请人：汤如俊  

报告摘要：Modern spintronic devices demand an efficient method to manipulate or switch a nanomagnet often with perpendicular magnetization. One of heavily investigated method is current driven spin orbit torques (SOTs). Such spin-orbit effect (SOE), including the spin Hall effect in the bulk of a nonmagnetic film and the Rashba-Edelstein effect at the interface between dissimilar films, enables interconversion between a charge current and a spin current. It is usually believed that the symmetry of these SOEs requires that the spin current, charge current and spin polarization are all orthogonal to each other. Therefore, for an in-plane current along the x-axis, it generates our-of-plane spin current (z-axis) with in-plane spin polarization (y-axis).The SOTs from such a spin current is not most efficient to switch a perpendicular magnetization.In this talk, we will demonstrate how the spin polarization can be rotated to be perpendicular direction (z-axis).We will discuss the implications of our observations on the fundamental understanding of the spin-orbit effects, as well as on the potential application in spin-orbit torque based magnetic memories.  

报告人简介：John Q. Xiao, a Fellow of American Physical Society, received his BS degree in physics from Nanjing University, China.He received his MS and Ph.D degrees in physics from the Johns Hopkins University in 1989 and 1993, respectively.Between 1993 and 1995, he was a post doctoral fellow at the Department of Physics and Astronomy at the Johns Hopkins University.He joined the University of Delaware as an Assistant Professor in 1995 and he is now a Unidel professor of Physics and Astronomy, affiliated professor at the Center of Composite Materials and Department of Electrical and Computer Engineering at the University of Delaware.His current research interests ranges over spintronics, soft magnetic materials, magnetic sensors, and microwave magnetic materials and devices.