Electrical Transport and Magnetic Properties of PEDOT-Ferrite Nanocomposites

We have studied the temperature-dependent transport and magnetic properties of the nanocomposites, containing varied amounts of CoFe2O4, NiFe2O4, and Fe3O4 nanoparticles embedded in the conducting poly(3,4-ethylenedioxythiophene) or PEDOT matrix, in the temperature range 77-300 K. Resistivities of all the composites, including pure PEDOT follows the Mott VRH relation rho - rho T-0(-1/4) over the studied temperature range. This suggests that hopping is the mechanism of transport in these systems. Plots of (In rho - In rho(0))/A as a function of temperature for all the studied samples are found to collapse on a single curve. Although, the conduction mechanism does not change with nanoparticle inclusions in the polymer matrix, the hopping parameters change in the nanocomposites. Magnetic studies of ferrite nanoparticles and nanocomposites show signature of superparamagnetic blocking, with a distribution of particle size. The spin structure on the surface of any particle is different from that of the core. POLYM. COMPOS., 32: 629-638, 2011. (C) 2011 Society of Plastics Engineers