Synthesis and Characterization of CoFe2O4 Nanoparticles Dispersed in a Silica Matrix by a Sol−Gel Autocombustion Method

• DOI: 10.1021/cm060650n
• Publication Date: 2006-07-17T05:00:42Z
• Authors: C. Cannas; A. Musinu; D. Peddis; G. Piccaluga
• Keywords: Superparamagnetism; Particle (ecology)

A very fast self-combustion reaction was applied for the first time to synthesis of a series magnetic CoFe2O4−SiO2 nanocomposites in wide range compositions (from 5 50 wt % CoFe2O4). Combining gelation method that adopts metal nitrates, citric acid and tetraethoxysilane as precursors with controlled thermal treatments, variety samples properties finely modulated were obtained. Particle formation evolution structural temperature investigated by analysis, X-ray diffraction, transmission electron microscopy, high-resolution nitrogen physisorption, IR, susceptibility measurements. It shown ammonium carboxylate complexes takes place all gel precursors, contributing control nucleation growth nanoparticles. Spherical particles narrow particle size distribution, uniformly dispersed matrix, are obtained diluted (N5, N10, N15), while nanoparticles more irregular shapes form high CoFe2O4 content (N30, N50). Magnetic evolve amounts treatments. The treated at 900 °C exhibit superparamagnetic behavior, expected dependence relaxation on size.