Fabrication, assembly and magnetic properties of nickel hollow nanoballs

Nanoshells composed of close-packed nickel nanoparticles have been fabricated on silica spheres via strong interaction between the metallic cations and ions of the support. The nickel hollow nanoballs can be self-assembled via magnetic field-assisted route, which is confirmed by the transmission electron microscopy. The magnetic properties of Ni nanoshells are discussed. It is expected that the prepared method can be extended to the synthesis of other hollow metal spheres.