Ferromagnetic relaxation by magnon-induced currents

TL;DR

This paper develops a theory to calculate spin wave relaxation times caused by magnon-electron interactions, highlighting the significant damping effects in high conductivity metals like permalloy, especially at high wave vectors.

Contribution

It introduces a comprehensive theoretical model for magnon-induced damping in thin film geometries across a wide frequency and wave vector range.

Findings

Wave vector dependent damping constant can reach 0.2 in permalloy.

Magnon-electron interactions can dominate observed relaxation.

The theory applies to various magnon frequencies and wave vectors.

Abstract

A theory for calculating spin wave relaxation times based on the magnon-electron interaction is developed. The theory incorporates a thin film geometry and is valid for a large range of magnon frequencies and wave vectors. For high conductivity metals such as permalloy, the wave vector dependent damping constant approaches values as high as 0.2, showing the large magnitude of the effect, and can dominate experimentally observed relaxation.