Template-free synthesis and self-assembly of aligned nickel nanochains under magnetic fields.

Well-aligned and uniform Nickel nanochains with diameters ranging from 20 to 110 nm have been synthesized using a simple template-free solution-phase method using environment friendly reagents under diverse temperature and magnetic field. Our results indicate that the size and morphology of as-prepared nanochains can be controlled by adjusting the reaction temperature and the applied magnetic fields, respectively. The formation of the aligned chains can be explained by the interactions of magnetic dipoles in the presence of magnetic field. Systematical magnetic measurements demonstrate that the saturation magnetization of the synthesized samples depends crucially on the particle size. Furthermore, the magnetic anisotropy of the well-aligned nickel nanochains is dominated by the shape anisotropy.