Oxygen content, cobalt oxide exsolution and defect structure of the double perovskite PrBaCo2O6−δ

Abstract

Cobalt oxide exsolution as a result of reduction of A-site understoichiometric double perovskite Pr_1−xBa_1−xCo₂O_6−γ was found. The reasons for inconsistencies in the experimental data on oxygen content in PrBaCo₂O_6−δ reported by different authors were discussed. The step-like changes of the oxygen content of PrBaCo₂O_6−δ with pO₂ in the temperature range 1023–1173 K were shown to correspond to reduction of exsolved Co₃O₄ to CoO. The defect structure analysis of PrBaCo₂O_6−δ was carried out using the conventional Kröger–Vink approach. The model proposed for the defect structure of PrBaCo₂O_6−δ was shown to coincide completely with available data on the oxygen content and crystal structure of this double perovskite.