Magnetic properties of Co, Ni, Pt and their alloy nanoparticles formed in SiO2 by ion beam synthesis

Nanoparticles of metallic platinum, nickel, cobalt and a Co–Pt alloy have been synthesized within a 100 nm silica film by ion implantation and thermal annealing. The spatial distribution, size and structure of the resulting nanoparticles are shown to depend on the specific metal species, even for chemically similar metals such as Co and Ni. Dual implantation with Co and Pt is further shown to be an effective means of producing Co–Pt alloy nanoparticles, with the alloy nanoparticles exhibiting a higher magnetic remanence and coercivity than Co or Pt nanoparticles alone.