Strain driven anisotropic magnetoresistance in antiferromagnetic La$_{0.4}$Sr$_{0.6}$MnO$_{3}$

TL;DR

This study explores how strain influences anisotropic magnetoresistance in antiferromagnetic La$_{0.4}$Sr$_{0.6}$MnO$_{3}$ thin films, revealing strain-dependent AMR behaviors and magnetic ordering without ferromagnetic transition.

Contribution

It demonstrates strain-induced variations in AMR and magnetic ordering in AFM La$_{0.4}$Sr$_{0.6}$MnO$_{3}$ thin films, including a previously unreported AMR behavior under tensile strain.

Findings

Compressive strain enhances AMR up to 63%.

Tensile strain induces a metal-insulator transition.

No global ferromagnetic phase transition observed.

Abstract

We investigate the effects of strain on antiferromagntic (AFM) single crystal thin films of La$_{1-x}$Sr$_{x}$MnO$_{3}$ (x = 0.6). Nominally unstrained samples have strong magnetoresistance with anisotropic magnetoresistances (AMR) of up to 8%. Compressive strain suppresses magnetoresistance but generates AMR values of up to 63%. Tensile strain presents the only case of a metal-insulator transition and demonstrates a previously unreported AMR behavior. In all three cases, we find evidence of magnetic ordering and no indication of a global ferromagnetic phase transition. These behaviors are attributed to epitaxy induced changes in orbital occupation driving different magnetic ordering types. Our findings suggest that different AFM ordering types have a profound impact on the AMR magnitude and character.