X-RAY-ABSORPTION SPECTROSCOPIC AND MOSSBAUER STUDIES OF REDOX AND CATION-ORDERING PROCESSES IN MANGANESE FERRITE

MnFe2O4 samples were prepared by the thermal decomposition of a freeze -dried MnFe2-formate precursor. Depending on the decomposition conditi ons, such as temperature and oxygen partial pressure, ferrites with di fferent oxidation state and cation distribution were formed. X-ray abs orption spectra of the ferrite samples were recorded at the Fe-K-and M n-K-edges to determine the Fe-and Mn-valence states. The site occupati on ratio of Fe cations on tetrahedral (A) and octahedral (B) sites of the spinel structure was obtained from Mossbauer spectra taken at 4.2 K in an external magnetic field of 6 tesla.