Interface Structure of an Epitaxial Cubic Ceria Film on Cubic Zirconia

Abstract

A cubic CeO2 (001) film with a thickness of ∼58 nm was grown epitaxially on Y2O3‐stablized cubic ZrO2 by oxygen‐plasma‐assisted molecular‐beam epitaxy (OPA‐MBE). The interface was characterized using high‐resolution transmission electron microscopy (HRTEM). The interface exhibited coherent regions separated by equally spaced misfit dislocations. When imaged from the [100] direction, the dislocation spacing is 3.3 ± 0.5 nm, which is slightly shorter than the expected value of 4.9 nm calculated from the differences in lattice constants given in the literature, but is fairly consistent with that of 3.9 nm which was calculated using the lattice mismatch measured by electron diffraction. Thus, the results presented here indicate that the lattice mismatch between the film and the substrate is accommodated mainly by interface misfit dislocations above some critical thickness.