Controlling Spin Polarization Direction in Spin Orbit Torques

Title: Controlling Spin Polarization Direction in Spin Orbit Torques

Speaker: Prof.  John Q. Xiao

Location: Room 101, Physical science Building

Time: 14:00-15:00p.m. Nov 20th, 2018

Abstract: 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.