Synthesis and magnetic properties of CoFe2O4 nanoparticles confined within mesoporous silica

We report here the synthesis and magnetic properties of cobalt ferrite (CoFe2O4) nanoparticles inside the nanoscale channels of highly ordered mesoporous silica SBA-15. Formation of CoFe2O4 nanoparticles inside the mesoporous channels was realized by impregnation of cobalt salt and iron salt precursors into the channels of the SBA-15, followed by calcination at different temperatures (400–1000 °C) in air. The products were characterized by X-ray diffraction (XRD), field emission scanning and transmission electron microscopies (FESEM and TEM), and nitrogen adsorption–desorption isotherm measurements. As per results, a typical characteristic of the obtained materials is that the mesoporous channels of SBA-15 are partially filled by CoFe2O4 nanocrystallites. In consequence, these materials exhibit open, ordered 2D hexagonal frameworks, which are very similar to that of the pristine SBA-15 except for the reduced dimension and specific surface area. Magnetic properties of the obtained materials show strong dependence on the calcination temperature. The maximum-value combination of the saturation magnetization (Ms), the remnant magnetization (Mr) and the coercivity (Hc) is obtained from the sample prepared at 1000 °C. Moreover, compared with the pure CoFe2O4 powder prepared at the same temperature, the CoFe2O4 incorporated SBA-15 composite possess higher magnetic parameters (Ms, Mr and Hc).