Crossed ratchet effects for magnetic domain wall motion

TL;DR

This paper investigates how asymmetric hole patterns influence magnetic domain wall motion, revealing two crossed ratchet effects that depend on the wall's shape, supported by experiments and a generic theoretical model.

Contribution

It demonstrates the existence of two opposite ratchet effects in magnetic domain walls due to asymmetric patterning, supported by experimental observations and a generic $$-model analysis.

Findings

Two crossed ratchet effects with opposite signs identified

The effects depend on whether the domain wall is flat or kinked

A simple $$-model captures the essential physics

Abstract

We study both experimentally and theoretically the driven motion of domain walls in extended amorphous magnetic films patterned with a periodic array of asymmetric holes. We find two crossed ratchet effects of opposite sign that change the preferred sense for domain wall propagation, depending on whether a flat or a kinked wall is moving. By solving numerically a simple $\phi^4$-model we show that the essential physical ingredients for this effect are quite generic and could be realized in other experimental systems involving elastic interfaces moving in multidimensional ratchet potentials.