MAGNETIC PROPERTIES OF NANOPARTICLES FORMED IN SOL-GEL FILMS BY ION IRRADIATION OR THERMAL PROCESSING

摘要

Ion irradiation of gel films prepared from mixtures of triethoxysilane with Fe and Ni nitrates permits to obtain a precipitation of metallic particles in a glassy matrix, because of the reduction ability of the hydrido group of the precursor for Fe~(3+) and Ni~(2+) ions. The metal particles, with a narrow range of sizes, exhibit a superparamagnetic behavior in a static field of low amplitude. However, their testing by electron spin resonance put into evidence a correlation of the spins parallel to the film surface.