Electronic structure and unusual magnetic properties of diluted magnetic semiconductors Pb1-x-ySnxScyTe

Abstract

We synthesize a single-crystal Pb1-x-ySnxScyTe ingot and investigate the magnetic properties (2.0 ≤ T ≤ 300 K, B ≤ 3 T) of alloys cut from it (x = 0.045–0.175, y ≤ 0.04). At low temperatures, all samples exhibit paramagnetic contribution to the magnetization, which contradicts the generally accepted model of doping-induced rearrangement of the electronic structure of alloys and is most likely due to the paramagnetism of electrically neutral Sc2+ ions or their clusters. In p-type samples, a high-temperature ferromagnetic ordering with a Curie temperature as high as TC = 145–150 K is found, presumably due to the RKKY hole-mediated interaction of Sc2+ ions. We obtain dependences of the concentration of paramagnetic ions, of the paramagnetic Curie-Weiss temperature Θ and of the Curie temperature TC on the concentrations of scandium and tin. At temperatures T < 100 K, the spin-glass-like behavior of magnetization and ferromagnetic hysteresis loops in the field dependences of magnetization are detected, indicating the formation of a mixed ferromagnetic–spin glass phase.