Synthesis of Size-Controlled fcc and fct FePt Nanoparticles

We report the synthesis of FePt magnetic nanoparticles using Na 2 Fe(CO) 4 and Pt(acac) 2 as reagents. This method allows good control over particle stoichiometry and ensures efficient mixing of Fe and Pt atoms in the alloy at the atomic scale. The use of a variety of different high boiling solvents and different surfactants allows control over particle size. Materials can be prepared in the disordered face-centered cubic (fcc) structural form and converted to the high magnetocrystalline anisotropy face centered tetragonal (fct or L 1 0 structure) at lower temperatures than those prepared by other routes. By using solvents such as nonadecane, docosane, and tetracosane, we can prepare samples directly in the fct form. Preformed fcc particles prepared by this method can also be transformed in solution to the fct structure. Samples have been characterized by a combination of diffraction, electron microscopy, thermogravimetric, and magnetic measurements.