Magnetic domain wall creep and depinning: a scalar field model approach

TL;DR

This paper introduces a scalar-field model to simulate magnetic domain wall dynamics, capturing creep and depinning behaviors, and analyzing how disorder affects depinning fields in quasi-two-dimensional magnetic systems.

Contribution

The paper presents a simple scalar-field model that accurately reproduces domain wall creep and depinning phenomena, enabling direct comparison with experimental protocols.

Findings

Depinning field increases with mean grain size.

The model captures thermally activated creep regimes.

Different disorder implementations affect depinning behavior.

Abstract

Magnetic domain wall motion is at the heart of new magneto-electronic technologies and hence the need for a deeper understanding of domain wall dynamics in magnetic systems. In this context, numerical simulations using simple models can capture the main ingredients responsible for the complex observed domain wall behavior. We present a scalar-field model for the magnetization dynamics of quasi-two-dimensional systems with a perpendicular easy axis of magnetization which allows a direct comparison with typical experimental protocols, used in polar magneto-optical Kerr effect microscopy experiments. We show that the thermally activated creep and depinning regimes of domain wall motion can be reached, and the effect of different quenched disorder implementations can be assessed with the model. In particular, we show that the depinning field increases with the mean grain size of a Voronoi tessellation model for the disorder.