Spin torque due to non-uniform Rashba spin orbit effect

Abstract

Following the early theoretical descriptions of the spin-orbit-induced spin torque [S. G. Tan, arXiv:0705.3502 (2007); S. G. Tan, Ann. Phys. 326, 207 (2011)]10.1016/j.aop.2010.11.014, the first experimental observation of such effect was reported by L. M. Miron, Nature Mater 9, 230 (2010). We present in this article three additional spin torque terms that arise from the non-uniformity in magnetization space of the Rashba spin-orbit effect. We propose a simple Rashba gradient device consisting of a heterogeneous trilayer structure, which could potentially lower switching current by n orders of magnitude, where n = -log10(|ΔM|/|M|) is a measure of the magnetization change across the device. © 2012 Copyright 2012 Author(s). This article is distributed under a Creative Commons Attribution 3.0 Unported License.