LAUSR

Abstract The effect of cerium insertion in sol-gel derived (Ba0.5Sr0.5)(Fe1-xCex)O3-δ (x = 0 – 1) powders has been investigated by Raman spectroscopy and findings correlated with crystalline phases present. A perovskite-type (ABO3) cubic phase of composition (x = 0) displays no Raman band but cerium substitution of iron is shown to induce distortion via BO6 octahedra tilt and to displace B-ion from its centro-symmetrical location besides expansion (due to its large ionic radius) with formation of an orthorhombic structure of lower symmetry (space group Pmnb or D4h16), characterized by several Raman bands including ~ 342 and 350 cm−1, 467 cm−1, and ~599 cm−1 associated with symmetric stretching of oxygen ions around B-ion, occupation of some cerium at A-site and/or F2g mode of CeO2, and occurrence of oxygen vacancies, respectively. The creation of anion vacancies makes the compounds useful for industrial application, viz., for obtaining pure oxygen from air.