Epitaxial phase stabilization in thin films of complex oxides

Abstract

A survey of experimental results is given presenting the successful growth of oxide epitaxial thin films in thermodynamic conditions (T, pressure, p(O₂), composition), which are far from those necessary for the stable existence of these phases in polycrystalline state. The unstable-in-bulk BaCu₃O₄, NdMn₇O₁₂, rare earth nickelates RNiO₃ and unusual phase relations in R–Ba–Cu–O systems are the examples. The stabilizing effect was observed in thin films only if the epitaxial growth was induced. The effect is thought to be of thermodynamic origin, rather than of kinetic one, and it is supposed to be the result of the low surface energy of coherent interfaces formed at the epitaxy.