Decoration of multiwalled carbon nanotubes with CoO and NiO nanoparticles and studies of their magnetism properties.

Multiwalled carbon nanotubes (MWNTs) have been successfully decorated with magnetic CoO and NiO nanoparticles via the interaction of M(NH(3))x(2+) (M = Co,Ni) ions and the carboxyl groups on the surface of acid-treated MWNTs. The obtained composites were characterized by X-ray diffraction, scanning electron and transmission electron microscopies. The soaking time plays an important role in the preparation of the composites. Magnetic measurements indicate that both the CoO/MWNT and NiO/MWNT composites present superparamagnetic behavior which can be attributed to the small size of CoO and NiO nanoparticles.