Probing punctual magnetic singularities during magnetization process in FePd films

TL;DR

This study uses Lorentz microscopy and simulations to investigate magnetic singularities, specifically vertical Bloch lines and Bloch points, within domain walls of FePd thin films during magnetization.

Contribution

It provides direct observation and analysis of magnetic singularities like VBLs and Bloch points in FePd films, linking domain shapes to their internal structures.

Findings

Identified regions of abrupt magnetization reversal as VBLs.

Correlated bubble domain shapes with VBL structures.

Probed Bloch points within domain walls.

Abstract

We report the use of Lorentz microscopy to observe the domain wall structure during the magnetization process in FePd thin foils. We have focused on the magnetic structure of domain walls of bubble-shaped magnetic domains near saturation. Regions are found along the domain walls where the magnetization abruptly reverses. Multiscale magnetic simulations shown that these regions are vertical Bloch lines (VBL) and the different bubble shapes observed are then related to the inner structure of the VBLs. We were thus able to probe the presence of magnetic singularities as small as Bloch points in the inner magnetization of the domain walls.