The effect of Mn doping in FePt nanopartides on the magnetic properties of the Ll_0 phase

摘要

FePtMn nanoparticles with a narrow size distribution and an average diameter of 3 nm were synthesized by the chemical reduction of Fe(acac)_3 and Pt(acac)_2 by NaBH_4 and the thermal decomposition of Mn_2(CG)_(10) in phenyl ether. The as-made nanoparticles have a disordered face-centred cubic (fcc) structure, which transformed after thermal treatment at 650 deg C to an ordered face-centred tetragonal (fct) structure, possessing coercivity values up to 13.7 kOe at room temperature. The coercivity of the annealed samples depends on the amount of Mn added to the reaction mixture, with the coercive field increasing significantly with the partial substitution of Pt by Mn, while the partial substitution of Fe by Mn does not affect the magnetic properties strongly.