Growth and magneto-optical properties of Bi25FeO40 crystals with heavy Co/Fe co-doping

This paper focuses on the magneto-optical properties of sillenite Bi25FeO40 crystals rather than optofractive, optoelectronic, piezoelectric and other properties. The Bi25FeO40 crystals with heavy Co3+ and Fe3+ co-doping were successfully grown into centimeter size by the top-seeded solution growth method. The thermal stability of crystal structure was improved. Annealing in oxygen atmosphere can greatly reduce oxygen vacancy defects, thereby improving the transmittance of the crystal. After doping Co3+ and Fe3+, Fe-O-Fe, Fe-O-Co and Co-O-Co superexchange interactionis formed in the crystal, which greatly enhances the magnetism of the crystal. Not only the magnetic but also the magneto-optical properties were significantly enhanced by co-doping Co3+ and Fe3+.