Evolution of magnetic bubble domains in the uniaxial ferromagnet CeRu$_2$Ga$_2$B inferred from the Hall effect and ac magnetic susceptibility

TL;DR

This study investigates the evolution of magnetic bubble domains in the uniaxial ferromagnet CeRu$_2$Ga$_2$B using Hall effect, ac magnetic susceptibility, and magnetic force microscopy, revealing a transition from trivial to topological spin textures.

Contribution

It demonstrates the presence and evolution of topological Hall effect and magnetic bubbles in CeRu$_2$Ga$_2$B, highlighting uniaxial anisotropy's role in topological spin textures.

Findings

Finite topological Hall effect observed in the ordered phase.

Magnetic bubbles evolve from trivial to topological with increasing field.

Potential to discover new topological magnetic materials with uniaxial anisotropy.

Abstract

We study the Hall effect, AC magnetic susceptibility ($\chi_{\rm ac}$), and magnetic force microscopy of the uniaxial ferromagnet CeRu$_2$Ga$_2$B with a centrosymmetric crystal structure. We observe a finite topological Hall effect (THE) within the ordered phase before the magnetization is polarized by applied field. By comparing the field dependences of the area fraction of the magnetic bubbles, the derivative of $\chi_{\rm ac}$, and the THE signal, we deduce that the magnetic bubbles of CeRu$_2$Ga$_2$B evolve from the trivial to topological spin texture with field. Our findings will be utilized to expand the search for magnetic materials hosting the topological spin textures to ones with uniaxial anisotropy, and open a new possibility to tailor the topological spin texture.