AIP Digital Archive
We investigated the magnetization of the ultrafine cadmium ferrite particles formed during the coprecipitation method and discussed the origin of enhanced magnetization based on the magnetic properties. A transmission electron microscopy micrograph shows aggregation of fine particles having two kinds of shapes, fibrous and granular. X-ray diffraction patterns of the specimens prepared by the coprecipitation method are composed of peaks corresponding to CdFe2O4, Cd(OH)2, and α-FeO(OH). The pattern indicates that the peaks of CdFe2O4 are fairly broad, suggesting the formation of a very small crystallite, with an average size of ∼8 nm. The ultrafine CdFe2O4 particles exhibit ferromagnetic behavior and have a net magnetization of 89±5 emu/g at 6 K. These results suggest that there must be many ferromagnetic clusters consisting of Fe3+ ions at the B sites around Fe3+ ions at the A site by the A–B interactions. Thus, such a change in the distribution of Fe3+ ions in the ultrafine CdFe2O4 particles results in increasing magnetization with decreasing particle size. © 1996 American Institute of Physics.
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