Structural and Magnetic Properties of Fe55Co45 Nanoparticles Synthesized by Different Methods

Nanostructured Fe₅₅Co₄₅ powders were produced by two methods: a high energy ball milling and a polyol reduction process. All the synthesized samples of FeCo nanoparticles were annealed at 600°C for distinct durations under argon. Structural properties of samples were analyzed by XRD, using the Rietveld method, and by transmission electron microscopy. We showed the formation of a bcc single phase structure for all samples with an average size of 41 nm and 20 nm for nanoparticles prepared by the polyol method and by the high energy ball milling, respectively. No additional peaks were observed which indicates the high purity of the samples. The magnetic measurements of all samples were done using the PPMS system. The highest saturation magnetization of 235 emu/g with a low coercivity of 76 Oe was obtained for the Fe₅₅Co₄₅ nanoparticles synthesized by the polyol process. The Fe₅₅Co₄₅ prepared by high energy ball milling showed only 225 emu/g.