ELECTRONIC-PROPERTIES OF GRAPHITE NANOTUBULES FROM GALVANOMAGNETIC EFFECTS

We have measured the magnetoresistance (MR) and Hall coefficient of state-of-the-art graphite nanotubule bundles. The apparent Hall coefficient is positive in the temperature and field ranges studied. At low temperatures, the conductivity or shows two dimensional weak localization behavior and the MR is negative; above 60 K the MR is positive and sigma increases approximately linearly with temperature, which is mainly due to an increase in the carrier concentration. The results show that a bundle of graphite nanotubules may best be described as a semimetal.