The mechanism of negative magnetoresistance in nondegenerate p-type Hg _1-xMn _xTe (x > 0.17) monocrystal

It is important to study the mechanism of negative magnetoresistance (MR) in magnetic semiconductors for the correct understanding of the sp-d interactions between carriers and magnetic ions. In this work, temperature-dependent Hall effect (10-300 K) and magnetic susceptibility (5-300 K) are measured for the study of negative MR and paramagnetic enhancement of nondegenerate p-type Hg _1-xMn _xTe (x > 0.17) monocrystal. As temperature decreases, both negative MR and susceptibility show the same behaviors, each of which contains an exponentially changing temperature function exp(-K/T). According to the theory of impurity energy level in semimagnetic semiconductor, magnetic field can lead to the spin-splitting of acceptor level and result in reducing the binding energy of acceptors, which is responsible mainly for the negative MR in nondegenerate p-type Hg _1-xMn _xTe monocrystal.