Sign Reversal of anisotropic magnetoresistance in La0.7Ca0.3MnO3/STO ultrathin films

TL;DR

This study reports strain-induced sign reversal of anisotropic magnetoresistance in ultrathin La0.7Ca0.3MnO3 films on STO, revealing how tensile strain influences magnetic properties near the Curie temperature.

Contribution

It demonstrates the first observation of strain-induced AMR sign reversal in ultrathin LCMO/STO films and links it to tensile strain effects on magnetization orientation.

Findings

Sign reversal of AMR observed at 4 nm thickness

Large AMR values near Curie temperature in 6 nm films

Tensile strain influences magnetization easy axis rotation

Abstract

We present the observation of strain induced sign reversal of anisotropic magnetoresistance (AMR) in LCMO (LCMO) ultrathin films (thickness 4 nm) deposited on STO (001) substrate (STO). We have also observed unusually large AMR in LCMO/STO thin films with thickness of 6 nm below but close to its Curie temperature (TC) which decrease as the film thickness increases. The sign reversal of AMR (with a maximum value of - 6) with magnetic field or temperature for the 4 nm thin film may be attributed to the increase in tensile strain in the plane of the thin film which in turn facilitates the rotation of the magnetization easy axis.