Spin torque due to non-uniform Rashba spin orbit effect

摘要

Following the early theoretical descriptions of the spin-orbit-induced spin torque[S. G. Tan et al., arXiv:0705.3502 (2007); S. G. Tan et al., 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 et al., Nature Mater9, 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 = ?log 10(|Δ M |/| M |) is a measure of the magnetization change across the device.