CoFe2O4 nanoparticles hosted in silica xerogels

Magnetic nanocomposites CoFe2O4/SiO2 were synthesized by a sol–gel process. By controlling the thermal treatment temperature and through the addition of hydrochloric acid, it was possible to obtain composites with different particle sizes and magnetic properties. It was remarkable that the addition of acids to the sols provided a way to increase average particle size and to narrow the particle size distribution of cobalt ferrite in the composites.