Asymmetric Magnetoresistance of Single-Walled Carbon Nanotubes Filled by Nickel

Paper presents the results of experimental investigations of magnetoresistance of single-walled carbon nanotubes in wide interval of magnetic field at room temperature Single-walled carbon nanotubes have been obtained by the electric arc method using nickel particles as a catalyst. For purification synthesized carbon nanotubes have been treated with hydrochloric acid. It is shown that for bulk specimen of purified carbon nanotubes there is effect of asymmetric magnetoresistance. This effect arises due to the presence in the specimen of inhomogeneous transverse Hall voltages caused by small inclusions of the magnetic phase. Thus, the presence of even a small amount of magnetic impurity remaining in the carbon nanotubes after the purification process causes the appearance of asymmetric magnetoresistance, while other magnetoresistive effects associated with the presence of a magnetic phase, in particular, the giant magnetoresistive effect, are not detected for investigated carbon nanotubes.