Growth and relaxation of (Zr,Y)O2 epitaxial layers analyzed by XRD reciprocal space mapping

Very thin polycrystalline and epitaxial yttria doped zirconia films have been realized using sol–gel processing. The lattice mismatch between the sapphire substrate and the zirconia crystals induces high misfit strain that we have determined using X-ray diffraction. Epitaxial films made of islands with sizes of several tens of nanometers are under very high stresses which are relaxed by the appearance of structural defects into the cubic zirconia crystals or by structural phase transition from the cubic to tetragonal zirconia form.