Anisotropic transport properties and topological Hall effect in the annealed kagome antiferromagnet FeGe

TL;DR

This study reveals anisotropic transport and a topological Hall effect in annealed FeGe kagome antiferromagnets, highlighting the interplay between charge density waves, magnetic transitions, and non-trivial spin textures.

Contribution

It reports the observation of anisotropic resistivity, Hall effects, and a field-induced topological Hall effect linked to spin textures in annealed FeGe, advancing understanding of magnetism and topology in kagome materials.

Findings

Anisotropic resistivity and Hall effects observed in FeGe.

Field-induced topological Hall effect linked to spin textures.

Charge density wave transition and spin-flop transition identified.

Abstract

Electron correlation often gives birth to various orders in quantum materials. Recently, a strongly correlated kagome antiferromagnet FeGe is discovered to undergo a charge density wave transition inside the A-type antiferromagnetic state, providing an opportunity to explore the interplay between charge order and magnetism. Here, we reported the observation of anisotropic resistivity and Hall effect, along with a topological Hall effect, in the annealed FeGe crystals. As the current flows along the \emph{ab}-plane, the temperature dependence of $\rho_{ab}$ exhibits a distinct resistivity loop related to a first-order transition at $T_{cdw}$. The applied magnetic fields do not alter $T_{cdw}$ but can induce a spin-flop transition at $H_{sf}$. Consequently, a field-induced large topological Hall effect is observed in the canting antiferromagnetic (CAFM) state below $T_{cant}$, which is possibly attributed to the non-trivial spin texture during the spin-flop process. Whereas, as current is parallel to \emph{c}-axis, both the field-induced transitions in $\rho_{c}$ and $\chi_{c}$ disappear. Instead, the Hall resistivity in the annealed FeGe significantly exhibits a deviation from the linear field-dependent. These findings provide valuable insight into revealing the interplay among magnetism, charge order and topology in the kagome magnets.