Mössbauer spectroscopic and x-ray diffraction studies of Fe/SiO2 nanocomposite soft magnetic materials

Nanocomposite high resistive soft magnetic materials Fe/SiO2 (Fe volume fraction 50%) have been synthesized using a wet chemical reaction method. A series of metal-ceramic Fe/SiO2 nanocomposite powder samples were obtained by annealing the precursor at temperatures from 400 to 900 °C in the presence of a reducing agent. The compositions of the precursor and the successive heat-treated samples have been investigated by 57Fe Mossbauer spectroscopy and x-ray diffraction, which revealed that the annealing process reduces nanosize granular ferrihydrite to α-Fe, and indicated that 800 °C is the optimum annealing temperature.