Nonlinear microscopic relaxation of uniform magnetization precession

TL;DR

This paper analyzes nonlinear microscopic relaxation mechanisms in magnetization precession, revealing how different processes affect relaxation rates and damping, with implications for magnetic dynamics modeling.

Contribution

It provides a unified analysis of both direct and indirect nonlinear relaxation processes in magnetization dynamics, extending the understanding beyond linear approximations.

Findings

Relaxation rate for direct processes scales with oscillation frequency.

Indirect processes introduce additional relaxation proportional to excitation level.

Effective damping exceeds Landau-Lifshitz-Gilbert damping in nonlinear regimes.

Abstract

Dynamic relaxation for nonlinear magnetization excitation is analyzed. For direct processes, such as magnon-electron scattering and two-magnon scattering, the relaxation rate is determined from the linear case simply by utilizing the magnetization oscillation frequency for nonlinear excitation. For an indirect process, such as slow-relaxing impurities, the analysis gives an additional relaxation term proportional to the excitation level. In all cases the effective magnetization damping is increased compared to Landau-Lifshitz-Gilbert damping.