Structure and magnetic properties of Fe-Pd silica composites prepared by sequential ion implantation

The nanostructural and magnetic properties of Fe-Pd/SiO2 granular solids prepared by sequential ion implantation have been investigated. Nanostructural features depend on the relative Pd/Fe implanted dose and, in particular, in the Pd50Fe50 sample 2-6 nm size nanoparticles with the disordered FCC structure are formed. At low temperatures Fe-Pd composites have open hysteresis loops with coercivity fields of some mT and large magnetic moment per Fe atom (2.8 mu(B)), In only-Fe and Fe-Pd composites the nanoparticles are superparamagnetic at room temperature and the blocking temperature increases from 20 K, for the only-Fe sample, to 110 K, for Fe50Pd50 sample.