Oxide Ion Conduction of BaCe_0.80Zr_0.10Y_0.10O_3-δ Thin Film with Oxygen Vacancies

Abstract

A BaCe_0.80Zr_0.10Y_0.10O_3-δ (BCZY) thin film with a- and c-axes orientations has been deposited on Al₂O₃ (0001) substrates by Radio Frequency magnetron sputtering. The lattice constants of a- and c-axes decrease with increasing the substrate temperature (T_sub) during sputtering deposition. The as-prepared BCZY thin film has the mixed valence states of Ce⁴⁺ (4f⁰) and Ce³⁺ (4f¹L) with oxygen vacancies created by high T_sub. The electrical conductivity increases with increasing T_sub, but it does not depend on oxygen partial pressure in the intermediate temperature (IMT) region between 400 and 600°C. The Ce³⁺ state at the LUMO level of the BCZY thin film is larger than that of BCZY bulk ceramic in which oxide ion conduction has not been observed. These results indicate that the BCZY thin film with oxygen vacancies has the high oxide ion conduction, which is required for electrolytes of solid oxide fuel cells in IMT region.