Spin Transfer Without Spin Conservation

TL;DR

This paper develops a comprehensive theory of spin-transfer effects in inhomogeneous magnetic systems that does not rely on spin conservation, enabling analysis of magnetization dynamics with spin-orbit interactions.

Contribution

It introduces a general framework for spin-transfer phenomena applicable to systems with spin-orbit coupling, extending beyond traditional conservation-based models.

Findings

The theory can predict coherent magnetization precession and switching.

It estimates spin-transfer efficacy in systems with spin-orbit interactions.

Application to a toy model demonstrates the theory's practical utility.

Abstract

We propose a general theory of the spin-transfer effects that occur when current flows through inhomogeneous magnetic systems. Our theory does not rest on an appeal to conservation of total spin, can assess whether or not current-induced magnetization precession and switching in a particular geometry will occur coherently, and can estimate the efficacy of spin-transfer when spin-orbit interactions are present. We illustrate our theory by applying it to a toy-model two-dimensional-electron-gas ferromagnet with Rashba spin-orbit interactions.