Mössbauer spectroscopy as a probe of magnetic states in La0.5Ca0.5FeO3−δ perovskite

Charge disproportionation in La0.5Ca0.5FeO3−δ perovskite has been detected by zero-field Mössbauer spectra from 20 K to room temperature. On the basis of the parameters of center shifts and hyperfine fields, Mössbauer spectra identified that the iron ionic states are Fe3+ and Fe5+ below 150 K, Fe3+, Fe4+ and Fe5+ in the intermediate temperature region, as well as Fe3+ and Fe4+ above 220 K. At low temperatures, the system exhibits a cluster-glass-like state resulting from competition between antiferromagnetic interaction of Fe3+–Fe3+ and ferromagnetic interaction of Fe3+–Fe5+.