Ultrafine FePt nanoparticles have been synthesized via a novel chemical solution synthesis route. Without using a reducing agent, the stoichiometric FePt nanoparticles were produced by the decomposition of iron acetylacetonate and platinum acetylacetonate in octyl ether in the presence of oleic acid and oleyl amine as the surfactants. The particle size was found to be around 2 nm with a narrow size distribution. The particles were then deposited on substrates and heat treated afterwards. Upon annealing, the nanoparticles sintered together to form continuous thin films and at the same time to transform from disordered face centred cubic (fcc) structure to the highly anisotropic ordered face centred tetragonal (fct) structure and therefore magnetic hardening was realized in the thin films. Coercivity up to 27 000 Oe at room temperature has been obtained in the annealed samples. The very high coercivity indicates a highly completed fcc-fct phase transition which may be related to the very fine original particle size.
ASJC Scopus subject areas
- Materials Science(all)
- Mechanics of Materials
- Mechanical Engineering
- Electrical and Electronic Engineering