Conductivity Mismatch and Voltage Dependence of Magnetoresistance in a Semiconductor Spin Injection and Detection Structure

This work studies the voltage dependence of magnetoresistance in a semiconductor spin injection and detection structure. The voltage dependence of the spin dependent interface resistance at a ferromagnet semiconductor interface is investigated and spin diffusion models are used to evaluate the voltage dependence of magnetoresistance. We find that the voltage dependence of magnetoresistance is similar to that in magnetic tunnel junctions. Using our model for spin injection in a ferromagnet-oxide-semiconductor junction, the variation of magnetoresistance ratio with semiconductor doping and oxide thickness has been studied.