119Sn and 57Fe M?ssbauer study of the local structure of perovskite-type ferrites CaFe2 ? x N x O5 ( N = Sc, Al) and manganite CaMn7O12

Anion-deficient substituted ferrites Ca₂Fe_{2 − x} N _x O₅ (N = Sc³⁺, Al³⁺) and mixed manganite CaMn₇O₁₂ have been investigated by ¹¹⁹Sn and ⁵⁷Fe probe M?ssbauer spectroscopy. The mechanism of charge compensation for heterovalent impurity Sn⁴⁺ ions in the structure of the ferrite Ca₂Fe₂O₅ has been established. The presence of nonequivalent crystallographic positions of manganese cations, caused by their charge ordering in the structure of the manganite CaMn₇O₁₂, is shown. Magnetic ordering of Mn³⁺ and Mn⁴⁺ cations in the octahedral sublattice of CaMn₇O₁₂ at T < T _M2 ≈ 90 K is established. Original Russian Text ? A.V. Sobolev, I.A. Presnyakov, K.V. Pokholok, V.S. Rusakov, T.V. Gubaidulina, A.V. Baranov, G. Demazeau, 2007, published in Izvestiya Rossiiskoi Akademii Nauk Seriya Fizicheskaya, 2007, Vol. 71, No. 9, pp. 1347–1354.