Synthesis and magnetic properties of face-centered-cubic and hexagonal-close-packed Ni nanoparticles through polyol process

The Ni nanoparticles with fcc or hcp phases have been synthesized in tetraethylene glycol by using the modified polyol process. The crystal structure has been controlled by changing the polyol/Ni mole ratio and the reaction temperature. The saturation magnetization of the as-prepared particles depends on the relative volume fraction of the hcp phase. The x-ray diffraction and extended x-ray absorption fine structure studies suggest the formation of pure fcc and hcp Ni phases. The hcp Ni particles show nonmagnetic behavior and thermally stable below 673 K.