Defect structure of xY2O3 · (1 − x)TiO2 (x = 0.5–0.58) solid solutions

Abstract

X-ray diffraction characterization with monochromatic synchrotron X-rays has demonstrated that xY2O3 · (1 − x)TiO2 (x = 0.5–0.58) solid solutions consist of a fluorite-like (Fm3m) disordered phase and a nanoscale (≃40–1000 nm) pyrochlore-like (Fd3m) ordered phase of the same composition, coherent with the disordered phase. In the composition range of the solid solutions (0.5 ≤ x ≤ 0.58), the lattice parameter of the fluorite-like phase follows Vegard’s law. The formation of nanodomains with different degrees of order is shown to be caused by the internal strain due to the high density of structural defects in their unit cells. The materials obtained in this study possess enhanced sorption capacity and can be used as catalysts, catalyst supports, gas sensors, etc.