Electronic transport properties of multiwall carbon nanotubes/yttria-stabilized zirconia composites

The electrical conductivity of a composite prepared by dispersing multiwall carbon nanotubes in yttria-stabilized tetragonal zirconia matrix, and subsequent spark plasma sintering, is studied. The dc conductivity of the composites follows a scaling law of the type sigma proportional to(p-p(c))(t), yielding for the percolation concentration p(c) = 0.017 and for exponent t = 3.3. The experimental result of the temperature of the conductivity suggests that for temperatures larger than 35 K, conduction can be attributed to thermal fluctuation induced tunneling of the charge carriers through the insulating zirconia separating by the multiwall carbon nanotube clusters. At lower temperatures, variable range hopping conduction may be a dominant conduction mechanism. (c) 2007 American Institute of Physics.