Correlation between the electronic and atomic structure, transport properties, and oxygen vacancies on La0.7Ca0.3MnO 3 thin films

We present a study of the role of oxygen vacancies on the atomic and electronic structure and transport properties on a 20 nm thick La 0.7Ca0.3MnO3 film grown by the pulsed laser deposition method on a SrTiO3 (001) substrate. The results show that oxygen vacancies induce an atomic structure modification characterized by the movement of the La/Ca cations to the perovskite regular position, by the reduction of the MnO6 basal plane rotation, and by a cooperative tilting of the octahedra along the out-of-plane direction. The out-of-plane lattice parameter increases due to the reduction of the Mn valence upon oxygen vacancies creation. As a consequence, a shift of the Metal-to-Insulator transition to lower temperatures is found to occur. We discuss the influence of the competitive phenomena of manganese valence and Mn-O-Mn bond distortion on the transport properties of manganite thin films. © 2014 AIP Publishing LLC.The authors are grateful to the SpLine staff for their valuable help and to the financial support from the Spanish MINECO and Consejo Superior de Investigaciones Cientificas under Grant Nos. MAT2011-23785 and 20106OE013.Peer Reviewe