Anomalous Hall resistivity and possible topological Hall effect in the EuAl4 antiferromagnet

We report the observation of anomalous Hall resistivity in single crystals of EuAl4, a centrosymmetric tetragonal compound, which exhibits coexisting antiferromagnetic (AFM) and charge-density-wave (CDW) orders with onset at T-N similar to 15.6 K and T-CDW similar to 140 K, respectively. In the AFM state, when the magnetic field is applied along the c-axis direction, EuAl4 undergoes a series of metamagnetic transitions. Within this field range, we observe a clear humplike anomaly in the Hall resistivity, representing part of the anomalous Hall resistivity. By considering different scenarios, we conclude that such a humplike feature is most likely a manifestation of the topological Hall effect, normally occurring in noncentrosymmetric materials known to host nontrivial topological spin textures. In view of this, EuAl4 would represent a rare case where the topological Hall effect not only arises in a centrosymmetric structure, but it also coexists with CDW order.

Automated summary

The study reports an anomalous Hall resistivity in single crystals of EuAl4, possibly due to the manifestation of the topological Hall effect, which normally occurs in noncentrosymmetric materials.