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Phys. Rev. B 42, 3386–3394 (1990)

Electrical-conduction mechanisms in polymer–copper-particle composites. II. (1/f)-noise measurements in the percolation limit

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C. Pierre and R. Deltour
Physique des Solides, CP233, Université Libre de Bruxelles, boulevard du Triomphe, B-1050 Bruxelles, Belgium

J. Van Bentum and J. A. A. J. Perenboom
Research Institute for Materials and High-Field Magnet Laboratory, University of Nijmegen, Toernooiveld, NL-6525 ED Nijmegen, The Netherlands

R. Rammal
Centre de Recherche sur les Très Basses Températures, Centre National de la Recherche Scientifique, Boîte Postale 166X, F-38042 Grenoble, France

Received 5 January 1990; published in the issue dated 15 August 1990

We have investigated the mechanisms of electrical conduction of polymer–copper-particle composites in the low-particle-concentration limit (dilute limit) by electrical-noise measurements. The 1/f flicker noise, observed close to the percolation threshold, has been studied as a function of the current through the sample, frequency (10-2104 Hz), and resistance (101109 Ω). In this paper we relate the total resistance noise measured on the samples to the local noise due to the different contacts between the particles. The resistance and noise power of the inhomogeneous medium is modeled by an extended effective-medium theory that includes a transition between two different conduction mechanisms near the percolation threshold. This model gives support to our hypothesis that the noise is produced by small electrical contacts between the particles, as well as the node-link picture introduced to characterize the conductive backbone preexisting at the percolation transition in the continuous percolation models.

© 1990 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevB.42.3386
DOI:
10.1103/PhysRevB.42.3386
PACS:
72.70.+m, 72.60.+g

See Also

See Also: C. Pierre, R. Deltour, J. A. Perenboom, and P. J. Van Bentum, Electrical-conduction mechanisms in polymer–copper-particle composites. I. Temperature and high-magnetic-field dependence of the conductivity, Phys. Rev. B 42, 3380 (1990).