Bias voltage dependence of magnetocurrent in magnetic tunnel transistors

The magnetocurrent of magnetic tunnel transistors is measured as a function of emitter/base bias voltage. A nonmonotonic bias dependence is found for magnetic tunnel transistors with a GaAs collector, whereas a monotonic decrease of the magnetocurrent with bias voltage is observed for transistors with a Si collector. A model including spin-dependent inelastic electron scattering in the ferromagnetic base layer and strong electron scattering at the base/collector interface can well account for the experimental results. The different bias dependences of magnetic tunnel transistors with GaAs and Si collectors is attributed to the different conduction band structures of these semiconductor collectors.