Theory of magnetoresistance in ferromagnetic junctions with a semimetal

Abstract We theoretically study the magnetoresistive effects in semimetal junctions with ferromagnetic electrodes. By using a simple tight-binding model and linear response theory, we show that the magnetoresistance ratio is enhanced in a region of crossover between semimetal and semiconductor, and that the enhancement can be understood from the partial density of states of the ferromagnets at the interface of the junction.