Strain States in YSZ/RE_2O_3 (RE = Er, Y) Multilayers as a Function of Layer Thickness and Their Effect on Interface Conductivity and Diffusion

摘要

In this study the strain states in alternating multilayers of an extrinsic O~(2-) ion conductor yttria stabilized zirconia (YSZ) and an insulator RE_2O_3 (RE = Er, Y) are investigated as a function of the layer thickness. Multilayers with narrow columnar crystallites and coherent phase boundaries were grown by pulsed laser deposition (PLD). A detailed strain analysis is performed by X-Ray Diffraction XRD, measuring distinct reflections in and perpendicular to the interface planes. Because of small columnar crystallites in the layers, the interfacial strain decays by shear with increasing distance from the interface. The extent of the strained interface regions in the YSZ layers is estimated from XRD data. By using a quantitative analytical model based on the pressure dependence of the free migration enthalpy for vacancies the results are compared to former published experimental data on O~(2-) ion conductivity and diffusion.