Domain instability during precessional magnetization reversal

TL;DR

This paper investigates the instability of spin waves during precessional magnetization reversal, revealing domain formation, chaos, and a novel effective dissipation concept in ferromagnetic systems.

Contribution

It introduces a new analysis of spin wave instabilities and domain chaos in precessional magnetization reversal, with a focus on non-equilibrium dynamics and effective dissipation.

Findings

Identification of spin-wave instability leading to domain formation

Observation of non-stationary domain chaos during instability

Introduction of an effective Gilbert dissipation with variable sign

Abstract

Spin wave equations in the non-equilibrium precessing state of a ferromagnetic system are found. They show a spin-wave instability towards growing domains of stable magnetization. Precession of the uniform magnetization mode is described by the Landau Lifshitz equation with the exponentially growing in time effective Gilbert dissipation constant that could have both signs. On the developed stages of the domain instability a non-stationary picture of domain chaos is observed.