Phase separation and epitaxial stabilization in BaCe0.5Zr0.5O3-films on SrTiO3

Thin perovskite films of the nominal composition BaCe0.5Zr0.5O3 on (001)-or iented SrTiO3 substrates were prepared by a chemical solution-deposition me thod to study epitaxial growth mechanisms for a high lattice mismatch (epsi lon approximate to 9.6%). The films were heat-treated to pyrolyze the precu rsor and initiate epitaxial growth. Experimental investigations by X-ray di ffraction (XRD) and conventional transmission electron microscopy (CTEM) ha ve shown that the films contain a high degree of grains that an slightly ti lted with respect to the normal of the substrate after heat treatment at 80 0 degrees C. Epitaxial stabilization of BaZrO3 (epsilon approximate to 7.4% ) is observed at the film -substrate interface ([100](001)BaZrO3) ([100](00 1)SrTiO3) after heat treatment at 1000 degrees C instead of the prepared co mposition, BaCe0.5Zr0.5O3, which is easily synthesized as a powder. The inf luence of the lattice mismatch on the destabilization of a solid solution i s discussed.