Improvement of magnetic properties of FePt nanoparticles by adding Mn

FePtMn nanoparticles were synthesized by the simultaneous reduction of iron acetylacetonate, platinum acetylacetonate, and manganese acetylacetonate with 1,2-hexadecanediol as the reducing reagent in the polyol process. The coercivity of annealed nanoparticles strongly depends on the amount of Mn addition. A maximum coercivity of 19 kOe at room temperature was obtained for (Fe32Pt68)(87)Mn-13 nanoparticles annealed at 700 degrees C for 1 h. The presence of Mn in the FePt L1(0) lattice may induce local strain so the ordering is accelerated. In addition, the high coercivity can presumably be partially related to the local bonding of Pt-Mn (or Fe-Mn) in the L1(0) structure.(c) 2005 American Institute of Physics.