Prediction of Giant Tunneling Magnetoresistance in RuO$_{2}$/TiO$_{2}$/RuO$_{2}$ (110) Antiferromagnetic Tunnel Junctions

TL;DR

This study predicts a giant tunneling magnetoresistance effect in RuO₂/TiO₂/RuO₂ (110) antiferromagnetic tunnel junctions using first-principles calculations, highlighting its robustness and underlying physics for spintronic applications.

Contribution

The paper introduces the prediction of a giant TMR effect in AFMTJs with RuO₂ electrodes and TiO₂ barriers, emphasizing the role of momentum-dependent conduction channels and interface effects.

Findings

Giant TMR effect predicted across various energies and barrier thicknesses.

TMR oscillates with increasing barrier thickness due to interface contributions.

The effect is explained by momentum-dependent spin-polarized conduction channels.

Abstract

Using first-principles quantum-transport calculations, we investigate spin-dependent electronic and transport properties of antiferromagnetic tunnel junctions (AFMTJs) that consist of (110)-oriented antiferromagnetic (AFM) metal RuO$_{2}$ electrodes and an insulating TiO$_{2}$ tunneling barrier. We predict the emergence of a giant tunneling magnetoresistance (TMR) effect in a wide energy window, a series of barrier layer thicknesses, and different interface terminations, indicating the robustness of this effect. We show that the predicted TMR cannot be explained in terms of the global transport spin-polarization of RuO$_{2}$ (110) but is well understood based on matching the momentum-dependent spin-polarized conduction channels of the two RuO$_{2}$ (110) electrodes. We predict oscillations of TMR with increasing barrier thickness, indicating a non-negligible contribution from the perfectly epitaxial interfaces. Our work helps the understanding of the physics of TMR in AFMTJs and aids in realizing efficient AFM spintronic devices.