Abstract
Silica gel films prepared from mixtures of triethoxysilane (TH) and Fe nitrate Fe(NO)3·9H2O were irradiated with various fluences of 3 MeV Au ions. Silicon 2p x-ray absorption (XAS) and L2,3 x-ray emission spectra of irradiated TH:Fe films are found to be very similar to those of SiO2, providing direct evidence of the formation of a glassy matrix. Fe L2,3 XAS shows the reduction of Fe3+ ions at low fluence, initially attributed to the formation of Fe metallic nanoparticles. Mössbauer spectra of films irradiated with higher ion fluences are well fitted by a singlet associated with superparamagnetic Fe particles and a doublet associated with Fe2+ ions in Fe–Si–O complexes.