Monodispersed FePt nanoparticles are synthesized by reduction of iron(II) acetylacetonate and platinum(II) acetylacetonate with 1,2-hexadecanediol as the reducing reagent in the polyol process.As-prepared FePt nanoparticles are chemically disordered with fcc phase.Transmission electron microscopy (TEM) images show a self-assembled particle array with an average particle size of 3 nm and a standard deviation about 10%.The transformation from chemically disordered fcc to chemically ordered Ll_0 phase is achieved by annealing at 650 deg C for 30 min in Ar atmosphere where the oxygen level is less than 1 ppm.Magnetic hysteresis measurements show a coercivity of 9.0 kOe at 293K,and 16.7 kOe at 5 K for the annealed FePt nanoparticles.
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