Liquid precursor route for hetero-epitaxy of Zr(Y)O2 thin films on (001) cubic zirconia

ZrO2-3 mol% Y2O3 single-crystal thin films with multiple variants were epitaxially formed on (100) cubic zirconia substrates. The films were prepared by spin-coating an aqueous zirconium acetate/yttrium nitrate solution onto the cubic zirconia substrates and subsequently heat-treated at temperatures between 1,100 and 1,400C. Electron diffraction and dark-field TEM observations showed that the film has tetragonal symmetry and consists of 50-100 nm variants with their c-axes aligned with one of the three substrate cube axes. Unrelaxed strain energy estimates indicate that the two variants with their ct-axis parallel to the substrate/thin film interface are energetically favorable