Mössbauer spectra of nanocrystalline Fe and Fe-Cr particles in sol-gel-derived SiO2 glass

Abstract

Ultrafine iron particles prepared by a sol-gel route are characterized by Mössbauer spectroscopy and transmission electron microscopy. The Mössbauer absorption patterns consist of a ferromagnetic component superposed on a superparamagnetic doublet. The intensity of the superparamagnetic doublet is found to be larger for particles having smaller average diameter. For very fine particles a diffused electron diffraction pattern is observed. It is also shown that the sol-gel technique could be used to prepare fine particles of a Fe-Cr alloy.