Synthesis and magnetic properties of aligned carbon nanotubes by microwave-assisted pyrolysis of acetylene

Aligned carbon nanotubes with high quality were synthesized at low temperature by microwave-assisted pyrolysis of acetylene in nitrogen atmosphere. The morphology and structure of the products were characterized by field-emission scanning electron microscopy, high resolution transmission electron microscopy, X-ray diffraction and Raman spectroscopy. The results indicated that the ACNTs with high crystallinity are densely packed, and some Fe3C nanoparticles are encapsulated in all parts of carbon tubes. In addition, the effect of the reaction temperature on the morphologies of the CNTs was also studied in detail. Magnetic measurements showed that the Fe3C-filled ACNTs display ferromagnetic properties at room temperature, and can be easily manipulated by an external magnetic field.