paper

Metamagnetism and anomalous magnetotransport properties in rare-earth-based polar semimetals AuGe ( Dy, Ho, and Gd)

arXiv:2405.00628 · doi:10.1103/PhysRevB.110.064409

Abstract

We report the magnetic, magnetoelastic, and magnetotransport properties of single crystals of polar magnets AuGe ( Dy, Ho, and Gd), grown by Au-Ge self-flux. Magnetization and magnetostriction measurements reveal multi-step metamagnetic transitions for the -axis magnetic field () for DyAuGe and HoAuGe, suggesting magnetic frustration in the triangular lattice of ions. The magnetic phase diagrams have clarified a close connection between the magnetoelastic property and the emergence of the intermediate metamagentic phase. The magnetic-field dependence of the resistivity and Hall resistivity reveal the semimetallic transport dominated by hole-type carriers, consistent with the behavior in a nonmagnetic analogue YAuGe. We also identify a signature of an anomalous Hall effect (AHE) proportional to the field-induced magnetization in Dy, Ho, and Gd. GdAuGe shows magnetic and transport behavior as reported in a previous study using Bi-flux grown single crystals, while the self-flux grown crystal shows larger magnetoresistance ( 345\%, at 1.8 K and 9 T) due to higher hole-type carrier mobility ( 6400 cm/Vs). Using the two-band model analysis considering the mobility change during the magnetization process, we extract the anomalous Hall conductivity: S/cm and S/cm for Dy and Ho, respectively, at 1.8 K with 9 T for . The magnitude of conductivity suggests a contribution of intrinsic origin, possibly related to the Berry curvature in the electron bands induced by the time-reversal symmetry breaking and the polar lattice.

11 pages, 9 figures

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