Real-time probing of magnetic domain wall dynamic

TL;DR

This paper introduces a real-time laser-based method for measuring magnetic domain wall velocity, compares it with traditional techniques, and models the influence of laser spot size on measurement accuracy.

Contribution

It presents a novel real-time probing technique for magnetic domain walls and a basic model to interpret measurements based on laser spot size and dendritic domain shapes.

Findings

The new method provides comparable velocities to traditional methods.

Laser spot size affects measurement results due to dendritic domain shapes.

A model accurately describes transit time as a function of spot size.

Abstract

We present a study of a very seldom used way of measuring magnetic domain wall velocity, which makes it possible to have a real-time probing of the domain movement in the area illuminated by a laser spot. We have compared this method to the most usual one: although the velocities are similar, the different method do not give the same results if the laser spot is too small. It can be explained by a dendritic shape of the domain wall. By changing the size spot, we propose a basic model which describes quite well the transit time in the laser spot as a function of its size and makes it possible to extract the velocity and the depth of the dendrites.