Electrical Transport and Magnetic Properties of PEDOT-Ferrite Nanocomposites

摘要

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 ρ = ρ_0 T~(-1/4) over the studied temperature range. This suggests that hopping is the mechanism of transport in these systems. Plots of (Inρ - lnρ_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 nanopar-ticle 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.