Nearest neighbor hopping in Cd0.83Mn0.17Te : In, controlled by persistent photoconductivity

We have measured the temperature dependence of the electrical resistivity o f a sample of the dilute magnetic persistent photoconductor Cd1-xMnxTe:In ( x = 0.17) as a function of persistent photocarrier concentration. We observ e a resistivity with the form rho = rho(3) exp(E-3/k(B)T) over the temperat ure range investigated (20-4 K), where E-3 and rho(3) vary with the carrier density in a manner that suggests a nearest neighbor hopping transport mec hanism. Magnetotransport measurements have also been made and we observe an anisotropic negative magnetoresistance (MR) at higher temperatures, which crosses over to a MR that is positive, and essentially isotropic, at low te mperatures. We interpret this behavior as a cross over from a mechanism tha t is sensitive to the length of the nearest neighbor hop (an "orbital" effe ct) to a situation where the interaction between the localized electron and the magnetic ions of the host becomes important. (C) 1999 Published by Els evier Science Ltd. All rights reserved.