Electronic properties of graphite nanotubules from galvanomagnetic effects

Abstract

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 \ensuremath{\sigma} shows two dimensional weak localization behavior and the MR is negative; above 60 K and MR is positive and \ensuremath{\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.