A novel method for synthesis of size-controlled L10 FePt nanoparticles

► The effect of HF on silicon surface causes the surface sufficiency for bonding to FePt NPs. ► Bonding of NPs to the surface prevent their coalescence during annealing at 600 °C. ► L10 FePt nanocrystals are synthesized and they are single size. ► Chemical ordered fct FePt NPs are 15 nm and ferromagnetic at room temperature. ► A surface with uniform distribution of ferromagnetic FePt nanocrystals were synthesized.