The effects of O reduction treatments upon the magnetic properties of La-deficient manganites, La1-ΔMnO3+δ and Sr- and Ca-doped manganites, La1-xMxMnO3+δ (M = Sr, Ca), were investigated. It was found that O reduction treatment of La1-ΔMnO3+δ under reduced O pressures of 103 to 1Pa resulted in a continuous change in the magnetization. Reduction treatment of La1-xMxMnO3+δ resulted in a negligible change under the same reduction conditions. Several possible models were used to explain the differing behaviors of the La-deficient manganites,. The most probable model was that the vacancies generated by the La deficiency, Δ, were partially replaced by Δ2 (=Δ-Δ1 ≤ Δ1) Mn ions to give both La and Mn site vacancies according to the formula La1-ΔVΔMnO3+δ → {La1-ΔMnΔ2VΔ1}{Mn1-Δ2VΔ2}O3+δ.

The Defect Chemistry of La1-ΔMnO3+δ. K.Nakamura: Journal of Solid State Chemistry, 2003, 173[2], 299-308