Defect chemistry of SrFe1−xZrxO3−δ

The data on oxygen content in SrFe_1−xZr_xO_3−δ (x = 0.05, 0.10, 0.15) were obtained by coulometric titration and successfully simulated by a defect chemistry model. Zirconium introduction into the B-sublattice was found to make a portion of anion sites inaccessible for oxygen ions. Zirconium stabilizes the cubic structure of as-prepared SrFe_1−xZr_xO_3−δ oxides but does not increase the oxygen content in them, suggesting local ordering of the oxygen sublattice. 10 % zirconium in the B-sublattice of ferrite was found to prevent its phase transition to brownmillerite, whereas 5 % was insufficient for this. The brownmillerite phase SrFe_0.95Zr_0.05O_3−δ and the cubic perovskite phase SrFe_0.9Zr_0.1O_3−δ were shown to be more resistant to reductive decomposition than Sr₂Fe₂O₅ and SrFeO_3−δ, respectively.