Strain-Induced Non-alter Compensated Magnet and Its Application to Magnetic Tunnel Junction Device Design

TL;DR

This paper introduces a shear-strain method to transform altermagnets into non-alternated compensated magnets, significantly enhancing tunneling magnetoresistance in magnetic tunnel junctions and broadening applications of magnetic materials.

Contribution

It proposes a shear-strain strategy to modulate altermagnets into non-alternated compensated magnets and demonstrates improved TMR in magnetic tunnel junctions.

Findings

Shear strain breaks rotational symmetry in altermagnets.

Enhanced TMR from 226% to 431% in RuO2-based MTJs.

Substantial TMR achieved in spin-degenerate paths.

Abstract

The recent proposal of altermagnetism has drawn widespread attention to antiferromagnet (AFM) exhibiting spin splitting, extending beyond the realm of sign-alternating spin splitting in momentum space protected solely by rotational symmetry. Herrin, we propose a shear-strain strategy that enables significant modulation of d-wave altermagnets into an non-alter compensated magnets. A comprehensive analysis combining the magnetic moment compensation characteristics of opposite spin sublattices with the distribution of spin-resolved conduction channels in momentum space under the [001] crystal orientation reveals that shear strain breaks the rotational symmetry of alternatmagnets. To explore the application potential of non-alter compensated magnets, we designe RuO2/TiO2/RuO2 magnetic tunnel junctions (MTJ) with three crystallographic orientations ((001), (110), (100)) and investigated their transport properties under shear strain. This non-alter electronic structure not only enhances the tunneling magnetoresistance (TMR) in spin-split paths of intrinsic RuO2 (226% to 431%) but also enables substantial TMR in spin-degenerate paths (from 0-88%)). Our work provides guidelines for broadening magnetic materials and device platforms.