Creep of current-driven domain-wall lines: intrinsic versus extrinsic pinning

TL;DR

This paper introduces a model for current-driven magnetic domain-wall motion considering both intrinsic and extrinsic pinning effects, revealing how different pinning regimes influence domain-wall velocity and creep behavior.

Contribution

The study provides a novel theoretical framework linking domain-wall creep to anisotropic pinning potentials and spin transfer torque effects, aligning with recent experimental observations.

Findings

Velocity depends on current and pinning regime

Creep exponent varies with spin transfer torque

Model aligns with recent experimental data

Abstract

We present a model for current-driven motion of a magnetic domain-wall line, in which the dynamics of the domain wall is equivalent to that of an overdamped vortex line in an anisotropic pinning potential. This potential has both extrinsic contributions due to, e.g., sample inhomogeneities, and an intrinsic contribution due to magnetic anisotropy. We obtain results for the domain-wall velocity as a function of current for various regimes of pinning. In particular, we find that the exponent characterizing the creep regime depends strongly on the presence of a dissipative spin transfer torque. We discuss our results in the light of recent experiments on current-driven domain-wall creep in ferromagnetic semiconductors, and suggest further experiments to corroborate our model.