Anomalous Hall resistivity and possible topological Hall effect in the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>EuAl</mml:mi><mml:mn>4</mml:mn></mml:msub></mml:math> antiferromagnet
Tian Shang, Yang Xu, Dariusz Jakub Gawryluk, Junzhang Ma, T. Shiroka, M. Shi, E. Pomjakushina
Abstract
We report the observation of anomalous Hall resistivity in single crystals of ${\mathrm{EuAl}}_{4}$, a centrosymmetric tetragonal compound, which exhibits coexisting antiferromagnetic (AFM) and charge-density-wave (CDW) orders with onset at ${T}_{\mathrm{N}}\ensuremath{\sim}15.6\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ and ${T}_{\mathrm{CDW}}\ensuremath{\sim}140\phantom{\rule{0.16em}{0ex}}\mathrm{K}$, respectively. In the AFM state, when the magnetic field is applied along the $c$-axis direction, ${\mathrm{EuAl}}_{4}$ 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, ${\mathrm{EuAl}}_{4}$ would represent a rare case where the topological Hall effect not only arises in a centrosymmetric structure, but it also coexists with CDW order.