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 uB). 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 110K, for Fe50Pd50 sample.