FeCo alloys are soft magnetic materials exhibiting low magnetic anisotropy constant (K Fe50Co50 = 1.5 x 104 J/m3) and the highest saturation magnetisation (Ms) among any other metal or alloy (bulk Ms: 240 – 245 emu/g). In addition, Co is the only element that increases the Ms when alloyed with Fe (55-65% Fe). These remarkable properties of FeCo nanoparticles (NPs) in conjunction with their high heating rate ensure high potential for biomedical applications, such as magnetic resonance imaging, magnetic particle imaging, magnetic drug targeting and especially magnetic fluid hyperthermia for cancer treatment. However, the synthesis of these NPs remains a challenging task due to their poor chemical stability. Herein we report the synthesis of FeCo NPs by thermal decomposition of organometallic precursors. The synthesis is based on the co-decomposition of Fe(CO)5 and Co(n3-C8H13)(n4-C8H12) in the presence of ligands under H2 gas pressure. During this study, we aimed to elucidate the effect of ligands, ligands’ concentration and ratio on the size, morphology and magnetic properties of the as-prepared NPs. Spherical FeCo@FexOy core-shell NPs were obtained with an average diameter less than 25 nm (Fig. 1), demonstrating high Ms values up to 194 emu/g. Among other techniques, HRTEM, XRD, SQUID and EDX mapping have been used for the determination of structural, compositional and magnetic characteristics of these NPs, as well as magnetic hyperthermia for investigating their efficiency to generate heat.

Synthesis of FeCo nanoparticles for magnetic hyperthermia

2019 Spring National Meeting

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