Hydrothermal synthesis of chain-like nickel microstructures with enhanced magnetic properties

Novel nickel chains assembled by submicrometre-sized spheres have been synthesised via a simple hydrothermal approach. Hydrazine was employed as both a ligand and a reducing agent, and polyvinylpyrrolidone (PVP) was used as the soft template. The nickel products were characterised by means of X-ray diffraction, scanning electron microscopy and transmission electron microscopy techniques. It was found that the amount of PVP and its long molecular chains played important roles in the formation of such microchains with a few branches. Magnetic measurement by a vibrating sample magnetometer illustrated that the nickel chains possessed ferromagnetic behaviour and significantly enhanced coercivity of 195 Oe compared with that of the bulk counterpart. The presented hydrothermal process could be adopted to fabricate chain-like micro/nanostructures of other materials.