A ferromagnetic oxide semiconductor as spin injection electrode in magnetic tunnel junction

TL;DR

This study demonstrates that ferromagnetic oxide semiconductor Ti1-xCoxO2-d can serve as a spin injection electrode in magnetic tunnel junctions, showing positive TMR at low temperatures, with potential for spintronic applications.

Contribution

It introduces Ti1-xCoxO2-d as a novel ferromagnetic semiconductor electrode for magnetic tunnel junctions, expanding materials options for spintronics.

Findings

Positive TMR of ~11% at 15 K

TMR decreases with temperature and vanishes above 180 K

TMR is affected by barrier quality and interface conditions

Abstract

A magnetic tunnel junctions composed of room temperature ferromagnetic semiconductor rutile Ti1-xCoxO2-d and ferromagnetic metal Fe0.1Co0.9 separated by AlOx barrier showed positive tunneling magnetoresistance (TMR) with a ratio of ~11 % at 15 K, indicating that Ti1-xCoxO2-d can be used as a spin injection electrode. The TMR decreased with increasing temperature and vanished above 180 K. TMR action at high temperature is likely prohibited by the inelastic tunneling conduction due to the low quality of the amorphous barrier layer and/or the junction interface.