Magnetoresistance of carbon nanotubes: From molecular to mesoscopic fingerprints

A magnetoresistance study of carbon nanotubes demonstrates that, for small diameters, the location of the chemical potential and the orientation of the magnetic field are parameters that enable tuning from positive to negative magnetoresistance, a phenomenon not related with weak localization. For larger diameters (greater than or equal to 10 nm), the conventional mesoscopic behavior of magonetotransport is recovered.