CATION DISTRIBUTION IN ZNFE2O4 FINE PARTICLES STUDIED BY NEUTRON POWDER DIFFRACTION

The structures of ZnFe2O4 fine particles prepared by a coprecipitation method have been studied by time-of-flight neutron powder diffraction at room temperature. The occupancy of Fe3+ ion at a tetrahedral A-site is 0.108 for sample A (crystallite size 960 angstrom) and 0.142 for sample B (290 angstrom), which indicates that the cation substitution increases with decreasing particle size. The large magnetization in ZnFe2O4 fine particles compared with bulk materials is ascribable to a strong coupling between Fe3+ ions at A- and B-sites due to the A-B interaction.