The magneto-optical Barnett effect and spin momentum transfer:Magnetization switching by circularly polarized light

TL;DR

This paper explores how circularly polarized light can induce ultrafast magnetization switching through a magneto-optical Barnett effect and spin transfer, challenging traditional models and aligning with recent experimental observations.

Contribution

It introduces a new understanding of spin transfer via optical Barnett-like effects and predicts femtosecond magnetization reversal in thin films.

Findings

Optical Barnett effect can cause ultrafast magnetization switching.

Traditional Bloch and Landau-Lifshitz models do not capture this ultrafast process.

Predicted femtosecond reversal matches recent experimental results.

Abstract

The interaction of polarized light with a spin in the presence of dissipation is shown to be equivalent to a spin transfer process that can cause switching. In plasmas, the spin transfer is dominated by a spin-spin exchange term while at lower energy densities it is dominated by an optical Barnett-like effect. This latter effect is used in conjunction with optical phonons to predict femtosecond magnetization reversal believed to be recently measured in GdCoFe thin films. Conventional approaches based on the Bloch and the Landau-Lifshitz equations do not reproduce this ultrafast switching.