Pinning of Domain Walls in thin Ferromagnetic Films

TL;DR

This paper provides a comprehensive quantitative analysis of magnetic domain wall pinning in thin ferromagnetic films, linking microscopic disorder parameters to macroscopic pinning behavior across various materials and temperatures.

Contribution

It introduces a self-consistent framework to extract microscopic pinning parameters from domain wall velocity data, enabling comparison across different magnetic materials.

Findings

Quantitative estimates of pinning barrier heights and depinning thresholds.

Identification of a crossover in pinning regimes at low temperatures.

Correlation of microscopic disorder with macroscopic pinning properties.

Abstract

We present a quantitative investigation of magnetic domain wall pinning in thin magnets with perpendicular anisotropy. A self-consistent description exploiting the universal features of the depinning and thermally activated sub-threshold creep regimes observed in the field driven domain wall velocity, is used to determine the effective pinning parameters controlling the domain wall dynamics: the effective height of pinning barriers, the depinning threshold, and the velocity at depinning. Within this framework, the analysis of results published in the literature allows for a quantitative comparison of pinning properties for a set of magnetic materials in a wide temperature range. On the basis of scaling arguments, the microscopic parameters controlling the pinning: the correlation length of pinning, the collectively pinned domain wall length (Larkin length) and the strength of pinning disorder, are estimated from the effective pinning and the micromagnetic parameters. The analysis of thermal effects reveals a crossover between different pinning length scales and strengths at low reduced temperature.