Mechanism of formation of gamma-Fe2O3 particles in a silica gel

Isolated gamma-Fe2O3 nanoparticles in a silica matrix have been obtained by heating a gel obtained from a solution of nitrate salt and TEOS in ethanol at 400 degrees C. By changing the preparation conditions such as the concentration of iron salt and the treatment temperature, particles with an average diameter from 5 to 15 nm can be prepared. The presence of organic species inside the gel pore has been determined as essential to obtain the magnetic iron oxide phase which mechanism of formation takes place through a reduction-oxidation process. The magnetic properties of these nanocomposites indicate that this material has good potential for important technological applications. Further efforts are being conducted to narrow the particle size distribution.