Magnetic properties of glass-metal nanocomposites prepared by the sol-gel route and hot pressing

Glass-metal nanocomposite powders in the systems Fe/SiO<SUB>2</SUB> and Ni/SiO<SUB>2</SUB> have been prepared by the sol-gel technique followed by reduction treatment. Bulk nanocomposites are then fabricated by hot pressing these powders. The metal particle diameters range from 8.9 to 14.8 nm. The materials show enhanced coercivities, e.g., a maximum of 82 Oe in the case of Ni/SiO<SUB>2</SUB> and a maximum of 474 Oe in the case of Fe/SiO<SUB>2</SUB> systems. The Mössbauer spectra of Fe/SiO<SUB>2</SUB> samples are comprised of a ferromagnetic component superposed on a superparamagnetic doublet