Multicore magnetic FePt nanoparticles: controlled formation and properties

Research on magnetic nanoparticles (NPs) has become one of the most active and exciting fields in materials science. The challenge is to produce magnetic NPs with high magnetic saturation without exceeding the super-paramagnetic limit so that they may be used as non-permanent magnets in biomedicine and catalysis. FePt offers enhanced saturation magnetisation properties compared to iron oxide, however synthetic methods require fine-tuning to achieve these superior properties. Multicore FePt NPs up to 44 nm in diameter and composed of Pt rich FePt nanocrystals within an iron rich FePt matrix not previously seen in the literature are presented here. The results indicate that coordination of Fe and Pt intermediates with oleic acid and oleylamine respectively hinders deposition of each respective metal in the growth of discrete and multicore NPs.