Description:
Spin filter devices based on resonant tunneling antisymmetrical magnetic-barrier structures are proposed and the spin-polarization properties are described. These devices can be realized by depositing one or two ferromagnetic stripes with perpendicular magnetization on top of two-dimensional electron gas. It is remarkable that the spin-filter efficiency of the transmission probability and the conductance through these devices could be reached completely (∼100%) in resonance, and that constant voltage applied to the metallic stripe of the systems could tune the spin polarization. These interesting features may lead to a practical voltage controlled spin filter.