X-Ray Imaging of Mixed States of Skyrmions and Helices in FeGe

TL;DR

This study uses advanced X-ray microscopy to visualize and analyze the coexistence and transition between helical and skyrmion magnetic states in FeGe, revealing their topological relationship and transition mechanisms.

Contribution

It provides direct imaging evidence of the topological equivalence and transition states between helical and skyrmion magnetic configurations in FeGe.

Findings

Finite helices are deformable to skyrmions, indicating topological equivalence.

Transition states involve frozen Bloch points across the sample thickness.

Clear identification of magnetic states via X-ray microscopy.

Abstract

We report scanning transmission X-ray microscopy of mixed helical and skyrmion magnetic states in thin FeGe lamellae. This imaging of the out-of-plane magnetism allows clear identification of the different magnetic states, and reveals details about the coexistence of helical and skyrmion states. In particular, our data show that finite length helices are continuously deformable down to the size of individual skyrmions and are hence topologically equivalent to skyrmions. Furthermore, we observe transition states between helical and skyrmion states across the thickness of the lamella that are evidence for frozen Bloch points in the sample after field cooling.