First-principles study on tunnel magnetoresistance effect with Cr-doped RuO$_{2}$ electrode

TL;DR

This study uses first-principles calculations to explore how Cr-doped RuO₂ electrodes influence tunnel magnetoresistance in magnetic tunnel junctions, revealing a finite TMR effect driven by spin splitting.

Contribution

It demonstrates that Cr-doped RuO₂ can serve as an effective electrode material for MTJs, with a TMR effect explained by momentum-dependent spin splitting and local density of states.

Findings

Finite TMR effect observed in Cr-doped RuO₂ MTJs

TMR effect linked to momentum-dependent spin splitting

Qualitative understanding via local density of states

Abstract

We investigate the functionality of the $\mathrm{Cr}$-doped $\mathrm{RuO_{2}}$ as an electrode of the magnetic tunnel junction (MTJ), motivated by the recent experiment showing that $\mathrm{Cr}$-doping into the rutile-type $\mathrm{RuO_{2}}$ will be an effective tool to control its antiferromagnetic order and the resultant magnetotransport phenomena easily. We perform first-principles calculation of the tunnel magnetoresistance (TMR) effect in the MTJ based on the $\mathrm{Cr}$-doped $\mathrm{RuO_{2}}$ electrodes. We find that a finite TMR effect appears in the MTJ originating from the momentum-dependent spin splitting in the electrodes, which suggests that $\mathrm{RuO_{2}}$ with Cr-doping will work as the electrode of the MTJ. We also show that this TMR effect can be qualitatively captured using the local density of states inside the tunnel barrier.