Electrical transport properties of cobalt doped polyaniline in an aqueous ethanol medium were investigated in the temperature range 77 ⩽ T ⩽ 300 K, applying magnetic fields up to 1 T in the frequency range 20 Hz–1 MHz. The room temperature dc resistivity increases with increase in Co content. The dc resistivity and magnetoresistivity of these samples have been interpreted in terms of the variable range hopping theory. The frequency dependence of conductivity has been described by a power law σ(ω) ∝ ωS. The value of s is found to be temperature dependent, which shows a decreasing trend with temperature. The correlated barrier hopping model is the most likely mechanism for the electron transport. The different physical parameters were calculated from the experimental data.

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AlloysNominal Compositions (Wt Pct) Alloy I Al-7.35, Mo-0.75, V-0.75, C-0.08 max, Fe-0.3 max, Yt-0.005 max, O 2 -0.2 max, and rest Ti Alloy II Al-6.0, Zr-2.0, Mo-3.

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ABSTRACT:We investigated the electrical-transport properties of hydroiodic acid doped polyaniline in the temperature range 77-300 K, applying magnetic field strength to a maximum of 1 T in the frequency range 20 Hz-1 MHz. The direct-current conductivity was explained by variable range hopping theory, and the direct-current magnetoconductivity, which was positive, was interpreted by orbital magnetoconductivity theory. The alternatingcurrent (ac) conductivity was found to follow the universal dielectric response r 0 (f) ! f s , where r 0 (f) is the frequencydependent real part of the complex ac conductivity, f is the frequency, and s is the frequency exponent. The trend in the variation of s, the temperature dependence of the frequency exponent, corroborated the fact that the correlated barrier hopping was the dominating charge-transport mechanism. The ac conductivity also showed a positive variation with magnetic field, which could be interpreted by this theory.