Energy-dispersive surface X-ray scattering study of thin ceria overlayer on zirconia: Structural evolution with temperature

We have studied the structure of ultra-thin CeO2, overlayer on single crystals of Y stabilized cubic zirconia (ZrO2) by energy dispersive surface X-ray scattering. The overlayers were formed by depositing cerium metal and annealing in oxygen atmosphere. Three different crystallographic surfaces, (001), (011) and (111), were examined. We observed formation of CeO2, overlayer with thickness of 10-40 Angstrom and lateral coherence length of 20-70 Angstrom depending on the sample. In addition, we performed in situ temperature study of a sample with (001) surface. A zirconia crystal with cerium metal deposited on the surface was placed on a substrate heater and was annealed in air during in situ surface X-ray diffraction. We observed the formation of a ceria epitaxial him at 420 degrees C followed by a preferential grain growth at higher temperatures and finally the diffusion of Ce into the bulk above 700 degrees C. (C) 1998 Elsevier Science B.V. All rights reserved.