Synthesis and oxygen permeability of the perovskite-type oxides in the La–Sr–Fe–Mn–O system

The perovskite-type oxides, La1−xSrxFe0.5Mn0.5O3−d and Sr1−wFeyMn1−yO3−x, were synthesized and investigated regarding their electrical conductivity and oxygen permeability. La1−xSrxFe0.5Mn0.5O3−d for x = 0–0.5 exhibited semiconducting behavior below 400 °C and all the compounds exhibited metallic behavior above 500 °C, indicating electronic conduction. Increase of Sr content for La1−xSrxFe0.5Mn0.5O3−d and Fe3+/Mn4+ ratio for SrFeyMn1−yO3−d led to increase in oxygen vacancies in the perovskite lattice and enhanced oxygen permeability. Introduction of cation vacancies also enhanced the permeability of Sr1−wFe0.8Mn0.2O3−d and Sr0.8Fe0.8Mn0.2O3−d had the highest oxygen permeation rate of the compounds synthesized in this work.