PROPERTIES OF BUCKYTUBES AND DERIVATIVES

The structural, magnetic, and transport properties of bundles of buckytubes (buckybundles) have been studied. High-resolution electron microscopy (HREM) images have revealed the detailed structural properties and the growth pattern of buckytubes and their derivatives. The magnetic susceptibility of a bulk sample of buckybundles is −10.75 × 10−6 emu/g for the magnetic field parallel to the bundle axes, which is approximately 1.1 times the perpendicular value and 30 times larger than that of C60. The magnetoresistance (MR) and Hall coefficient measurements on the buckybundles show a negative MR at low temperature and a positive MR at a temperature above 60 K and a nearly linear increase in conductivity with temperature. The results show that a buckybundle may best be described as a semimetal. Using a stable glow discharge, buckybundles with remarkably large diameters (up to 200 μm) have been synthesized. These bundles are evenly spaced, parallel, and occupy the entire central region of a deposited rod. HREM images revealed higher yield and improved quality buckytubes produced by this technique compared to those produced by a conventional arc discharge.