The O non-stoichiometry, δ, of La1−xCaxCrO3−δ (x = 0.1 to 0.3) was measured by means of thermogravimetry as a function of PO2 between 1073 and 1373K, and the content of calcium, x. In any composition, δ became larger and was got closer to δ = x/2 with decreasing PO2. For a given PO2, the δ of La1−xCaxCrO3−δ increased with increasing temperature and x-value. There was almost no difference in O non-stoichiometry between Ca-doped lanthanum chromite and Sr-doped lanthanum chromite. Defect chemical analysis was performed taking defect interaction into consideration. The non-stoichiometry curves were reproduced well by the proposed defect model and the obtained thermodynamic parameters. The influence of defect interaction on defect formation energy could be mainly attributed to change in interatomic potential due to defect-induced lattice expansion.

Oxygen Non-Stoichiometry of the Perovskite-Type Oxide La1−xCaxCrO3−δ (x = 0.1, 0.2, 0.3). S.Onuma, K.Yashiro, S.Miyoshi, A.Kaimai, H.Matsumoto, Y.Nigara, T.Kawada, J.Mizusaki, K.Kawamura, N.Sakai, H.Yokokawa: Solid State Ionics, 2004, 174[1-4], 287-93