Mössbauer Spectroscopic Analysis of La1−xSrxFeO3−δ Perovskites

Herein, the effects of different Sr content doping on the crystal structure and electronic structure of La 1− x Sr x FeO 3− δ (LSFO‐ x , x = 0, 0.2, 0.5, 0.8, 1.0) are studied by X‐ray diffraction (XRD) and Mössbauer spectroscopy. It is shown in the XRD results that the structure of LSFO‐ x changes from orthorhombic (Pnma [#62]) to cubic (Pm‐3m (#221)) to tetragonal (I4/mmm (#139)) with increasing strontium doping. It is shown in Mössbauer spectrum analysis that with the gradual increase of Sr doping, iron ions finally change from +3 oxidation state to +4 oxidation state after passing through an intermediate oxidation state of +3.5. The Fe 3.5+ state can result from rapid electron exchange (Fe 3+ + Fe 4+ ⇋ Fe 4+ + Fe 3+ ) between iron ions of different oxidation states within the crystal structure; the study provides some reference for future research to study the effect of iron‐oxidation state on the specific activity of strontium‐doped LaFeO 3 .