| Abstract
| - X-ray absorption fine structure (EXAFS) and X-ray absorption near-edge structure (XANES) techniques atboth Fe and Co K-edges were used to investigate the formation of CoFe2O4 nanoparticles embedded in asilica aerogel matrix as a function of calcination temperature and CoFe2O4 content. In particular, nanocompositeaerogels containing relative CoFe2O4 amounts of 5 and 10 wt % and calcined at 450, 750, and 900 °C werestudied. The evolution of the nanophase with calcination temperatures depends on the composition. In thesample containing 10 wt % of nanophase, results indicate that CoFe2O4 nanocrystals were formed aftercalcination at 750 °C, whereas in the sample containing 5 wt % of nanophase, they were obtained only aftercalcination at 900 °C. Quantitative determination of the distribution of the iron and cobalt phase in the octahedraland tetrahedral sites of the spinel structure shows that cobalt ferrite prepared by sol−gel has a partially invertedspinel structure with a degree of inversion around 0.70.
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