Quantum Kinetic Theory of Current-Induced Torques in Rashba Ferromagnets

TL;DR

This paper develops a quantum kinetic theory to explain current-induced magnetic torques in Rashba ferromagnets, highlighting the role of spin-dependent lifetimes and spin-orbit coupling in switching behavior.

Contribution

It introduces a quantum kinetic framework for understanding current-induced torques in Rashba ferromagnets, emphasizing the importance of spin-dependent quasiparticle lifetimes and spin-orbit coupling.

Findings

Spin-dependent quasiparticle lifetimes are crucial for current-induced spin densities.

Analytic expressions for torque limits are derived from a simple model.

Spin-orbit coupling in the adjacent layer significantly influences switching strength.

Abstract

Motivated by recent experimental studies of thin-film devices containing a single ferromagnetic layer, we develop a quantum kinetic theory of current-induced magnetic torques in Rashba-model ferromagnets. We find that current-induced spin-densities that are responsible for the switching behavior are due most essentially to spin-dependent quasiparticle lifetimes and derive analytic expressions for relevant limits of a simple model. Quantitative model parameter estimates suggest that spin-orbit coupling in the adjacent metal normal magnetic layer plays an essential role in the strength of the switching effect.