Magneto-oscillatory behavior of carbon nanotube bundles

Low-temperature magnetoresistance measurements on pristine bundles revealed non-oscillatory magnetoresistance behavior comprising positive and negative components. However, upon intercalation of K-atoms, random oscillations about a large negative underlying trend were revealed—features that were also seen for some pristine bundles taken from the same source material. When plotted as magneto-conductance, the amplitude of these oscillations is comparable to that of the ‘universal’ conductance fluctuations recently observed for a single multiwall nanotube [Langer, L. et al, Phys. Rev. Lett. 76 (1996) 479]. This amplitude is temperature-independent below Tc∼3 K. An explanation of these observations is given within the framework of 3D weak localization theory.