Pinning theory of domain walls in helical magnets

TL;DR

This paper develops a theoretical framework for understanding the elasticity and pinning behavior of domain walls in helical magnets, highlighting effects of disorder, anisotropy, and vortex structures.

Contribution

It introduces a comprehensive theory describing domain wall elasticity, pinning mechanisms, and vortex array formations in helical magnets, including effects of disorder and anisotropy.

Findings

Domain walls perpendicular to the helical axis exhibit non-local elasticity.

Weak anisotropy and magnetic dilution cause non-local bulk pinning.

Pinning force varies with wall orientation, pitch angle, and impurity concentration.

Abstract

The theory of elasticity and pinning of domain walls in helical magnets is presented. Domain walls perpendicular to the helical axis show non-local elasticity and are marginally pinned by local disorder. Weak anisotropy combined with magnetic dilution leads however to a non-local bulk pinning effect. Domain walls with other orientations include generically vortex arrays, similar to type-II superconductors. Their pinning force is calculated as a function of wall orientation, pitch angle and impurity concentration. It is shown that metastable domains can vary between needle and pancake like shape.