Magnetoresistance of polypyrrole and polyacetylene

摘要

The magnetoresistance (MR) has been measured on polypyrrole doped with tetraethylammonium toluene-4-sulfonate (PPy(TOS), sigma_RT)=25 S/cm) and on polyacetylene ((CH)_x, sigma_RT=2X10~4 S/cm) in the temperature range from 1.3 to 4.2 K up to H=10 T. The data for PPy (TOS) show a positive MR, but for (CH)_x samples they show a positive MR with a maximum, the position of which shifts towards lower fields as the temperature decreases. The obtained data are explained in terms of the effect of the magnetic field on the variable range hopping (VRH).