A novel mathematical approach for defect concentration calculations proposed for oxides with rather small deviations from stoichiometry also applies to perovskite-type oxides with large ranges of O non-stoichiometry. Point-defect chemistry calculations were performed for YBa2Cu3O6.5+δ for which experimental equilibrium O partial pressure isotherms were well known. The model applied here described experimental results very well in the PO2 range of 10−5 to 10bar and for temperatures of between 450 and 800C.

Point Defect Chemistry of YBa2Cu3O6.5+δ. K.Conder, M.Stingaciu, E.Pomjakushina: Materials Research Bulletin, 2008, 43[5], 1195-202