Low-Temperature Magnetoresistance Studies on Composite Films of Conducting Polymer and Multiwalled Carbon Nanotubes

We report on low-temperature electrical conductivity and magnetoresistance (MR) measurements on composite films of conducting polyaniline (PANI) and multiwalled carbon nanotubes (CNT). The conductivity below 150 K follows Mott’s variable-range-hopping model in three dimensions. The MR of the CNT/PANI composite films is strongly dependent on temperature, magnetic field, and CNT loading. Evident transition from negative to positive MR was observed with lowering temperature, increasing magnetic field, or decreasing CNT loading. The positive and negative MR is discussed in terms of a wave function-shrinkage effect and a quantum interference effect on hopping conduction.