Curvature-driven AC-assisted creep dynamics of magnetic domain walls

TL;DR

This paper demonstrates that a weak AC magnetic field can significantly accelerate the curvature-driven collapse of magnetic domains in disordered ferromagnetic films, which is otherwise too slow to observe at room temperature.

Contribution

It introduces a novel AC-assisted method to observe and analyze the creep dynamics of magnetic domain walls affected by quenched disorder.

Findings

AC field enhances domain wall collapse rate

Analytical model accurately predicts the effect

Curvature-driven collapse becomes observable with AC assistance

Abstract

The dynamics of micrometer-sized magnetic domains in ultra-thin ferromagnetic films is so dramatically slowed down by quenched disorder that the spontaneous elastic tension collapse becomes unobservable at ambient temperature. By magneto-optical imaging we show that a weak zero-bias AC magnetic field can assist such curvature-driven collapse, making the area of a bubble to reduce at a measurable rate, in spite of the negligible effect that the same curvature has on the average creep motion driven by a comparable DC field. An analytical model explains this phenomenon quantitatively.