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

Abstract

Glass-metal nanocomposite powders in the systems Fe/SiO2 and Ni/SiO2 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/SiO2 and a maximum of 474 Oe in the case of Fe/SiO2 systems. The Mössbauer spectra of Fe/SiO2 samples are comprised of a ferromagnetic component superposed on a superparamagnetic doublet.