Anisotropic strains and magnetoresistance of La_{0.7}Ca_{0.3}MnO_{3}

TL;DR

This study investigates how anisotropic strains influence the magnetoresistance of La_{0.7}Ca_{0.3}MnO_{3} thin films grown on different substrates, demonstrating that lattice distortions can modulate their magnetic properties.

Contribution

It provides experimental evidence that external strains alter the lattice structure and magnetoresistance in La_{0.7}Ca_{0.3}MnO_{3} thin films, highlighting strain engineering as a control method.

Findings

Cubic unit cell samples exhibit smaller magnetoresistance.

Noncubic lattice structures show enhanced magnetoresistance.

Lattice distortion via strain controls magnetic properties.

Abstract

Thin films of perovskite manganite La_{0.7}Ca_{0.3}MnO_{3} were grown epitaxially on SrTiO_3(100), MgO(100) and LaAlO_3(100) substrates by the pulsed laser deposition method. Microscopic structures of these thin film samples as well as a bulk sample were fully determined by x-ray diffraction measurements. The unit cells of the three films have different shapes, i.e., contracted tetragonal, cubic, and elongated tetragonal for SrTiO_3, MgO, and LaAlO_3 cases, respectively, while the unit cell of the bulk is cubic. It is found that the samples with cubic unit cell show smaller peak magnetoresistance than the noncubic ones do. The present result demonstrates that the magnetoresistance of La_{0.7}Ca_{0.3}MnO_{3} can be controlled by lattice distortion via externally imposed strains.