Characteristic features of oxygen exchange in lanthanum-strontium manganites doped with iron

Based on the data of thermogravimetric analysis values oxygen index (3–δ) in manganite La 0.7 Sr 0.3 Mn 0.9 Fe 0.1 O 3-δ composition, obtained by solid-phase reaction technique, have been calculated. The sorption-desorption curves showed that processes release and absorption at p 2 = 10 Pa 400 are not reversible. minima derivative dδ/d t f ( T ) corresponding to maxima extraction rate indicate complex character changes desorption from manganite. decrease heating cooling 6.6 2.6 K/min resulted a significant change value ∆δ, indicating dependence anion mobility concentration magnet structure. It has revealed kinetics is well described exponential Cramers model, which implies no return desorbed sample. This model indicates non-stationarity diffusion flux through barrier during samples. calculation activation energy Merzhanov method various partial pressures shown initial stage , minimum Е а 103.7 kJ/mol δ 0.005) as vacancies increases, it rises reaching saturation 134.3 0.06). assumed with an increase vacancies, interaction occurs between them, followed their ordering formation associates.