Synthesis of spherical FePd and CoPt nanoparticles

${\mathrm{Co}}_{48}{\mathrm{Pt}}_{52}$ nanoparticles were prepared by the simultaneous chemical reduction of platinum acetylacetonate and the thermal decomposition of cobalt tricarbonyl nitrosyl. Similarly, ${\mathrm{Fe}}_{50}{\mathrm{Pd}}_{50}$ nanoparticles were prepared by the simultaneous reduction of palladium acetylacetonate and the thermal decomposition of iron pentacarbonyl. The average diameter for the ${\mathrm{Co}}_{48}{\mathrm{Pt}}_{52}$ particles was 7 nm, while the average diameter for the ${\mathrm{Fe}}_{50}{\mathrm{Pd}}_{50}$ particles was 11 nm. Films of the particles were cast onto silicon wafers from hydrocarbon solution. Only after annealing at 700 °C for three hours did the ${\mathrm{Co}}_{48}{\mathrm{Pt}}_{52}$ films transform to the ${\mathrm{L1}}_0$ phase. However there was no evidence for the tetragonal phase for the films containing ${\mathrm{Fe}}_{50}{\mathrm{Pd}}_{50}$ particles after annealing at 700 °C for three hours.