A metal-semiconductor composite model for the linear magnetoresistance in high magnetic field

A model for the linear magnetoresistance (MR) in high magnetic field is proposed by considering silver-rich Ag2+δSe and Ag2+δTe materials as two-phase (silver metal phase and semiconductor phase) composites. The model takes the MR as a function of magnetic field, temperature and the conductivity of the two phases without magnetic field. The model predictions are in good agreement with the available experimental data. It is inferred from the model that there is a critical volume fraction of silver metal phase, at which the MR reaches a maximum value. The values of the critical volume fraction of the silver metal phase are about 0.2 and 0.05 for the Ag2+δTe thin film and Ag2+δSe bulk, respectively. We interpret the occurrence of the critical volume fraction as a result of the percolation between silver particles in the material.