Anomalies in the dynamics of ferrimagnets near the angular momentum compensation point

TL;DR

This paper develops an analytical theory for domain wall dynamics in ferrimagnets near the angular momentum compensation point, revealing how spin oscillations and magnetic fields influence domain wall behavior.

Contribution

It introduces a new analytical model describing domain wall dynamics near the angular momentum compensation point in ferrimagnets, including post Walker regime analysis.

Findings

Spin oscillations suppress domain wall dynamics near Walker breakdown.

Increasing magnetic field enhances domain wall speed and mobility.

Anomalous domain wall behavior observed near the compensation point.

Abstract

In this paper, we elaborate analytical theory of domain wall dynamics close to the angular momentum compensation point based on non-linear dynamic equations derived from the effective Lagrangian of a ferrimagnet. Analysis of the precession angle and domain wall velocity oscillations in post Walker regime in a ferrimagnet is performed. In the framework of the proposed model, we explore dynamic processes in the Walker and post Walker regimes. We show that although spin oscillations quench the dynamics of domain walls near the Walker breakdown field, a further increase of the driving magnetic field increases domain wall speed and mobility. An anomalous behavior of domain wall dynamic properties near the angular momentum compensation point in ferrimagnets is discussed.