Mechanism of spin-polarized transport in perovskite oxide heterojunctions

A model of spin-polarized transport in perovskite oxide p-n heterostructures is introduced based on the weak Hund coupling and semiconductor energy band theory. The positive colossal magnetoresistance (CMR) effect in the heterojunction of La0.9Sr0.1MnO3/SrNb0.01Ti0.99O3 (LSMO/SNTO), which is composed of the negative CMR material LSMO and the nonmagnetic material SNTO, can be explained by using this model. Our theory paves a novel way for the understanding of the spin-polarized transport mechanism in these oxide heterostructures.