Electrical Transport and Magnetoresistance of Doped Polypyrrole

Tarek Fahmy, Moustafa T. Ahmed

Different doped samples of conducting polypyrrole (PPy) are prepared electrochemically at different current densities. The electrical transport of conducting polypyrrole is investigated in a wide range of temperature starting from 4.2 K to 300 K. It is observed that, for samples prepared at high current densities, the electrical conduction is dominated mainly by the mechanism based on variable range hopping in a wide temperature range. On the other hand, the magnetoresistance of polypyrrole is investigated in the temperature range from 1.2 K to 4.2 K and magnetic field from H=0 T to H= 10.3 T. It is observed that, PPy sample is characterized by large positive magnetoresistance. This obtained large positive magnetoresistance in the insulating regime is typically expected for VRH conduction.