Complex magnetic phase diagram in noncentrosymmetric EuPtAs

Abstract

We report the observation of multiple magnetic transitions in single crystals of EuPtAs using magnetization, transport, and thermodynamic measurements. EuPtAs crystallizes in the noncentrosymmetric tetragonal LaPtSi-type structure (space group $I{4}_{1}md$) and undergoes a second-order antiferromagnetic (AFM) transition at 14.8 K, which is followed by a first-order transition at about 7.5 K. Both transitions are suppressed by magnetic fields applied parallel and perpendicular to the $c$ axis, and multiple field-induced transitions are observed for both field directions, leading to complex temperature-field diagrams with a domelike magnetic phase for fields parallel to the $c$ axis. Moreover, the dependence of the low-temperature resistivity on the application of a training field, together with a lack of remanent magnetization, suggests the presence of multiple AFM domains in zero field.