Relaxation Mechanism for Ordered Magnetic Materials

TL;DR

This paper introduces a continuum-based relaxation mechanism for ordered magnetic materials that explains key experimental phenomena such as FMR linewidth scaling, temperature dependence, and anisotropy without adjustable parameters.

Contribution

It presents a novel continuum model for magnetic relaxation that aligns well with experimental data, contrasting previous microscopic approaches.

Findings

Explains the frequency scaling of FMR linewidth.

Accounts for 1/M temperature dependence.

Describes anisotropic magnetic relaxation.

Abstract

We have formulated a relaxation mechanism for ferrites and ferromagnetic metals whereby the coupling between the magnetic motion and lattice is based purely on continuum arguments concerning magnetostriction. This theoretical approach contrasts with previous mechanisms based on microscopic formulations of spin-phonon interactions employing a discrete lattice. Our model explains for the first time the scaling of the intrinsic FMR linewidth with frequency, and 1/M temperature dependence and the anisotropic nature of magnetic relaxation in ordered magnetic materials, where M is the magnetization. Without introducing adjustable parameters our model is in reasonable quantitative agreement with experimental measurements of the intrinsic magnetic resonance linewidths of important class of ordered magnetic materials, insulator or metals.