Anomalous increasing and recovery of the electrical resistivity and their sample-dependent suppression by the magnetic field in α-Sm2S3 single crystal

Rare earth sesquisulfide alpha-Sm2S3 having the orthorhombic crystal structure exhibits successive weakferromagnetic transitions at TC1 = 3.6 K and TC2 = 1.8 K. The alpha-Sm2S3 single crystals with apparently different directions of easy magnetization were grown using a chemical transport reaction method. In this study, we report on the anomalous electrical resistivity observed in samples with different easy magnetization axes (caxis or a-axis) and the influence of the magnetic field on it. Significant anisotropy and sample dependence in electrical resistivity were found. In the absence of a magnetic field, a sharp increase in electrical resistivity was noted around 5.5 K, followed by a subsequent decrease. The magnitude of this increase is enormous, exceeding a factor of 105. However, these anomalies were rapidly suppressed by applying a magnetic field, especially when the magnetic field was applied along the easy magnetization axis, regardless of the direction of electrical resistivity. The easy magnetization axis of the sample, the direction and magnitude of the applied magnetic field and the direction of current flow influenced the rho(T) in various ways and showed a close relation to the complicated variation of the magnetic structure. It was also clarified that the electrical resistivity along the easy magnetization axis is the smallest among the axes even at 300 K in both samples.