Bias dependent inversion of tunneling magnetoresistance in Fe∕GaAs∕Fe tunnel junctions

Abstract

The authors investigated spin dependent transport through Fe∕GaAs∕Fe tunnel junctions. The tunneling magnetoresistance (TMR) effect was probed for different types of Fe∕GaAs interfaces. For interfaces cleaned by hydrogen plasma the TMR effect is increased and is observable at room temperature. If an epitaxial Fe∕GaAs(001) interface is involved, the tunnel junction exhibits a bias dependent inversion of the TMR effect. This is a first experimental signature for band structure effects at an Fe∕GaAs interface and is relevant for spin injection experiments.