Articles written in Bulletin of Materials Science

    • Tuning magnetoresistance and electrical resistivity by enhancing localization length in polyaniline and carbon nanotube composites


      More Details Abstract Fulltext PDF

      We report low temperature electrical resistivity and magnetoresistance (MR) measurements of conducting polyaniline (PANI) and multiwalled-carbon nanotube (MWCNT) composites. We have used an in-situ oxidative polymer-ization method to synthesize hydrochloric acid-doped PANI composites with MWCNT weight percentages of 0, 5, 10 and 15. The temperature dependence of resistivity is studied from room temperature to 4.2 K and analysed by a Mott variable range hopping (VRH) model. The resistivity increases from 1.1 × 10⁻³ Ωm at 300 K to 65.75 Ωm at 4.2 K, almost four orders of the magnitude change with temperature for pure PANI. Whereas the PANI composite with 15% MWCNTs shows less variation from 4.6 × 10⁻⁴ to 3.5 × 10⁻² Ωm. The huge change in resistivity is due to the localization of charge carriers in the presence of disorder. At 4.2 K MR shows transition from positive to negative with higher MWCNT loading. Samples with 5 and 10% MWCNTs show positive MR, whereas the 15% MWCNT loaded sample shows negative MR. The positive and negative MR are discussed in terms of the wave function shrinkage effect and quantum interference effect on VRH conduction.

  • Bulletin of Materials Science | News

    • Editorial Note on Continuous Article Publication

      Posted on July 25, 2019

      Click here for Editorial Note on CAP Mode

© 2017-2019 Indian Academy of Sciences, Bengaluru.