Electronic phase transitions in Pr$_{0.5}$Ca$_{0.5}$MnO$_3$ epitaxial thin films revealed by resonant soft x-ray scattering

TL;DR

This study uses resonant soft x-ray scattering to reveal how epitaxial strain alters magnetic and orbital order in Pr$_{0.5}$Ca$_{0.5}$MnO$_3$ thin films, showing new magnetic phases and demonstrating a powerful technique for thin film magnetism analysis.

Contribution

It introduces a novel application of resonant soft x-ray scattering to investigate strain-induced magnetic and orbital modifications in manganite thin films.

Findings

Different magnetic ordering wave vector in films versus bulk

Altered magnetic easy axis due to epitaxial strain

Additional magnetic reordering transition at low temperatures

Abstract

We report the study of magnetic and orbital order in Pr$_{0.5}$Ca$_{0.5}$MnO$_3$ epitaxial thin films grown on (LaAlO$_3$)$_{0.3}$-(SrAl$_{0.5}$Ta$_{0.5}$O$_3$)$_{0.7}$ (LSAT) (011)$_c$. In a new experimental approach, the polarization and energy dependence of resonant soft x-ray scattering are used to reveal significant modifications of the magnetic order in the film as compared to the bulk, namely (i) a different magnetic ordering wave vector, (ii) a different magnetic easy axis and (iii) an additional magnetic reordering transition at low temperatures. These observations indicate a strong impact of the epitaxial strain on the spin order, which is mediated by the orbital degrees of freedom and which provides a promising route to tune the magnetic properties of manganite films. Our results further demonstrate that resonant soft x-ray scattering is a very suitable technique to study the magnetism in thin films, to which neutron scattering cannot easily be applied due to the small sample volume.