1/f noise through the metal-nonmetal transition in percolating composites

Abstract

We have measured the 1/f noise through the metal-nonmetal transition in carbon black/polymer composites as a function of temperature and doping. At the electronic transition, the resistivity power spectrum Sρ varies as Sρ ∼ ρQ, with Q = 2.77, in agreement with classical three-dimensional percolation. At lower temperatures, a crossover to tunneling-dominated transport occurs with Sρ ∼ In Sρlρ2. Our results show that 1/f noise can be a more sensitive technique than resistivity itself for probing transport behavior near a percolation-induced electronic transition. © 2000 American Institute of Physics.