Growth and characterization of filled carbon nanotubes with ferromagnetic properties

Strong vertically aligned Fe-filled multiwalled nanotubes have been synthesised by decomposition of ferrocene in a liquid source CVD process. By varying the reaction parameter such as deposition time, reaction temperature and precursor concentration we determined the influences on the length, diameter and filling yield of the carbon nanotubes. The length and the diameter of the nanotubes are only controlled by the ferrocene concentration in the gas phase and there is no influence on the deposition time. The filling yield achieved about 45 wt.%. Using alternating gradient magnetometry measurements really high coercivities, high magnetization moments and strong magnetic anisotropies with an easy magnetic axis parallel to the aligned nanotubes are observed. In addition, this LSCVD is highly suited for the high scale production of filled multiwalled carbon nanotubes with selected properties. (C) 2006 Elsevier Ltd. All rights reserved.