Inversion degree and saturation magnetization of different nanocrystalline cobalt ferrites

The inversion degree of a series of nanocrystalline samples of CoFe2O4 ferrites has been evaluated by a combined study, which exploits the saturation magnetization at 4.2 K and Fe-57 Mossbauer spectroscopy. The samples, prepared by sol-gel autocombustion, have different thermal history and particle size. The differences observed in the saturation magnetization of these samples are explained in terms of different inversion degrees, as confirmed by the analysis of the components in the Mossbauer spectra. It is notable that the inversion degrees of the samples investigated are set among the highest values reported in the literature. (c) 2008 Elsevier B. V. All rights reserved.