Electronic and magnetic properties of the diluted magnetic semiconductor Hg1-xMnxTe1-ySey

Abstract

Electrical resistivity, Hall coefficient and magnetoresistance for diluted magnetic semiconductor Hg_1-xMn_xTe_1-ySe_y crystals with y=0.01 and x=0.03, 0.06, 0.14, 0.30 have been measured in the temperature range 4.2-300 K and in magnetic fields up to 7 T. Negative magnetoresistances are observed at 4.2 K in all samples, which can be explained by the change of the acceptor activation energy in the magnetic field. The temperature and magnetic field dependences of the Hall coefficient and its sign reversal in a magnetic field can be explained quantitatively by the coexistence of three group of carriers, electrons and two types of holes with different mobilities. Magnetic susceptibility measurements using a SQUID, magnetometer in the temperature range 4.2-80 K reveal that these solid solutions show a paramagnetic behaviour and the sample with x=0.30 exhibits a spin-glass transition at a temperature lower than that of Hg_1-xMn_xTe_1-ySe_y with the same Mn content.