The microstructure and magnetic properties of nanocomposite Fe-x(SiO2)(1-x) materials

Nanocomposite Fe-x(SiO2)(1-x) samples were prepared using high energy ball milling. The microstructure and magnetic properties of these samples with d ifferent Fe contents and different ball milling time were studied using X-r ay diffraction (XRD), transmission electron microscopy (TEM), Mossbauer spe ctroscopy, and magnetic balance over a wide temperature range. The results indicated that the microstructure and magnetic properties were closely rela ted to the ball milling time and Fe contents. When the Fe content was less than 20 wt%, the sample after ball milling 80 hours demonstrated a very com plex microstructure. The small alpha-Fe grains and Fe clusters were implant ed in the SiO2 matrix, and there were also nanometer-scale sandwich network -like structures. The nanocomposite Fe,(SiO2), samples also displayed the c hange of magnetic properties, which results from their unique nanostructure , the grain size effect, the strong interface interaction and the interface -osmosis effect at the Fe-SiO2 boundaries. (C)1999 Acta Metallurgica Inc.