Chemical synthesis and characterization of hcp Ni nanoparticles

Hexagonal close-packed (hcp) Ni particles were prepared in the nanosize range (13–25 nm) by reduction of Ni(NO3)2 in polyethylene glycol (PEG) with various molecular weights. The reaction occurred in the presence of an equimolecular mixture of oleic acid and oleyl amine, which plays the role of a stabilizer and gives solubility to the nanoparticles in non-polar solvents. The crystal structure of Ni particles seems to be controlled by the molecular weight of the PEG molecule and subsequently the reaction temperature. The magnetic properties of the hcp Ni nanoparticles are also studied.