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

TL;DR

This study explores how interface quality and bias influence the tunneling magnetoresistance in Fe/GaAs/Fe junctions, revealing bias-dependent inversion linked to band structure effects, relevant for spintronics applications.

Contribution

It provides the first experimental evidence of bias-dependent TMR inversion caused by band structure effects at Fe/GaAs interfaces.

Findings

Hydrogen plasma cleaning enhances TMR at room temperature.

Epitaxial Fe/GaAs(001) interfaces show bias-dependent TMR inversion.

Band structure effects are significant in spin injection experiments.

Abstract

We investigated spin dependent transport through Fe/GaAs/Fe tunnel junctions. The tunneling magnetoresistance effect (TMR) was probed for different types of Fe/GaAs interfaces. For interfaces cleaned by hydrogen plasma the TMR effect is increased and 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 a Fe/GaAs interface and relevant for spin injection experiments.