Effect of Cu doping on the structure and phase transition of directly synthesized FePt nanoparticles

L10 ordered (FePt)100−xCux NPs have been directly synthesized at 320 °C by using hexadecylamine as the solvent. Cu additive influences the grain growth, chemical ordering, and magnetic properties of the FePt NPs. A coercivity of 4800 Oe was achieved for the (FePt)100−xCux nanoparticles with composition of Fe35Pt45Cu20. The enhancement of L10 ordering is attributed to the alloying of Cu with FePt, which promotes grain growth and increases the driving force for ordering through enhancing the ordering kinetics.181