Local structure in strained manganite thin films

Abstract

We report on a polarized x-ray absorption spectroscopy study, combining experimental measurements and ab initio calculations, of La0.7Sr0.3MnO3 films, epitaxially grown on tensile and compressive substrates. Measurements show significant modifications in the coordination shell around manganese atoms in the film plane for both substrates. We show that biaxial strain is locally accommodated in the coordination shell, by distortion of the MnO6 octahedron, without change in the tilt angle. The modifications of the near edge spectra were correlated to modification in the average Mn–O bond distance and distortion of the MnO6 octahedra. This distortion tending to localize the charge carriers may account for the decrease of the Curie temperature observed in thin films with respect to bulk systems.