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

Thin perovskite films of the nominal composition BaCe 0.5 Zr 0.5 O 3 on (001)-oriented SrTiO 3 substrates were prepared by a chemical solution-deposition method to study epitaxial growth mechanisms for a high lattice mismatch (e 9.6%). The films were heat-treated to pyrolyze the precursor and initiate epitaxial growth. Experimental investigations by X-ray diffraction (XRD) and conventional transmission electron microscopy (CTEM) have shown that the films contain a high degree of grains that are slightly tilted with respect to the normal of the substrate after heat treatment at 800 °C. Epitaxial stabilization of BaZrO 3 (e7.4%) is observed at the film-substrate interface ([100](001)BaZrO 3 ∥[100](001)SrTiO 3 ) after heat treatment at 1000 °C instead of the prepared composition, BaCe 0.5 Zr 0.5 O 3 , which is easily synthesized as a powder. The influence of the lattice mismatch on the destabilization of a solid solution is discussed.