Resonant tunnel magnetoresistance in epitaxial metal-semiconductor heterostructures

We report on resonant tunneling magnetoresistance via localized states (LS) through a ZnSe semiconducting barrier which can reverse the sign of the effective spin polarization of tunneling electrons. Experiments performed on $\mathrm{Fe}∕\mathrm{Zn}\mathrm{Se}∕\mathrm{Fe}$ planar junctions have shown that positive, negative, or even its sign-reversible magnetoresistance can be obtained, depending on the bias voltage, the energy of LS in the ZnSe barrier, and spatial symmetry. The averaging of conduction over all LS in a junction under resonant condition is strongly detrimental to the magnetoresistance.