X-ray photoelectron diffraction study of dopant effects in La0.7X0.3MnO3 (X = La, Sr, Ca, Ce) thin films

Abstract

We present and discuss element-specific x-ray photoelectron diffraction (XPD) patterns of La, Mn, O and the dopant ions Ca, Sr and Ce of various La0.7X0.3MnO (LXMO) films grown epitaxially on SrTiO3(001) substrates. The recorded XPD polar scans are explained in the framework of multiple-scattering cluster calculations, where in general a very good agreement between experimental and theoretical data has been found. Results for all thin films are compatible with a tetragonally distorted cubic perovskite structure with similar MnO6 network. Strong evidence for Mn-site termination was found in all thin films. Dopant locations on A-type sites were clearly confirmed for Sr in LSMO and Ca in LCMO films by means of XPD polar scans. The absence of surface-sensitive Ce3d diffraction features for Ce in LCeMO points to non-equivalent Ce sites and related near-surface disorder.