Magnetoresistance in p-type cadmium telluride doped with sodium

This paper gives an account of the observations that were made during experiments in which temperature dependent van der Pauw (vdP) measurements were conducted on sodium doped single crystalline CdTe. With the aid of the vdP technique, the resistivity of the sample was measured in the presence of an external transverse magnetic field. The measurements were conducted at temperatures that ranged from 24K all the way up to 300 K. The measurements indicated that at low temperatures, the resistivity of the sample increased significantly as the magnitude of the magnetic field perpendicular to the sample was raised from 0 T to 1.5 T. It was observed that the magnetoresistance (MR) decreased with increasing temperature. At 24 K, for an applied field of 1.5 T, the maximum MR was over 30%. Furthermore, it was also observed that the MR below 75K exhibited a more or less linear dependence on the magnetic field. At higher temperatures, the MR as a function of the applied magnetic field exhibited a quadratic dependence. The results seem to indicate that the linear MR is most likely due to inhomogeneity in the semiconductor. (C) 2015 AIP Publishing LLC.