Real-time probing technique of domain wall dynamic in perpendicularly magnetized film

We present the study of a rarely mentioned method for measuring the magnetic domain wall velocity, which makes it possible to have a real-time probing of the domain wall movement in the perpendicularly magnetized thin film. We have compared this technique in detail with the most common Kerr imaging method. The comparison results show interesting differences if the spot size is too small. It can be explained by the dendritic shape of the domain wall. By changing the size spot, we propose a basic model that 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 depth of the dendrites. By generalizing our method, it helps people to understand magnetic domain wall dynamics from the temporal dimension and helps the academic community to obtain intrinsic domain wall motion characteristics in the film sample, ultimately promoting the development of spintronic devices.