Preparation and magnetic properties of nickel nanoparticles via the thermal decomposition of nickel organometallic precursor in alkylamines

Nickel nanoparticles were prepared from the thermal decomposition of nickel(II) acetylacetonate in alkylamines and characterized by powder x-ray diffraction, transmission electron microscopy and magnetic measurement. The reaction temperature, heating rate and solvent type play an important role in the control over the crystalline phase. Depending on the reaction conditions, face-centered cubic (fee) or hexagonal close-packed (hcp) nickel nanoparticles can be obtained. Monodisperse nickel nanoparticles were also obtained by introducing surfactants. The results of magnetic characterization showed that the magnetic properties of the hcp nickel nanoparticles are quite different from those of the fee nickel nanoparticles.