Defect formation in double perovskites PrBaCo2−xCuxO5 +δ at elevated temperatures

• Oxygen disordering is incorporated in equilibrium defect model.
• Changes in concentration of oxygen defects with T and p(O2) are calculated.
• The pathway for oxygen transport in double perovskite structure is considered.
• The copper doping is shown to enhance electrical conductivity in PrBaCo2 -xCuxO5 +δ.

The variations of equilibrium oxygen content with oxygen pressure and temperature were measured in copper doped double perovskite cobaltite PrBaCo2 −xCuxO5 +δ. The results of thermodynamic analysis show that oxygen pressure decrease and temperature increase both favor the appearance of oxygen vacancies in O2 structural positions. It is suggested that oxygen migration over O3 positions in double perovskite cobaltites occurs via mediation of O2 positions. Copper doping is shown to facilitate formation of oxygen vacancies in O2 positions, which is expected to be advantageous for enhanced oxygen ion transport.