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Scaling Behavior of the Complex Conductivity of Graphite-Boron Nitride Percolation Systems

Published online by Cambridge University Press:  10 February 2011

Jungie Wu
Affiliation:
Physics Department, University of the Witwatersrand, PO Wits 2050, Johannesburg, South Africa.
D S McLachlan
Affiliation:
Physics Department, University of the Witwatersrand, PO Wits 2050, Johannesburg, South Africa.
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Abstract

Measurements of both components of the complex AC conductivity σ*m of continuum percolation systems, based on Graphite and hexagonal Boron Nitride, over a large frequency range, for samples near the conductor insulator composition, are reported. The results of the real part of σ*m (σmr) above the critical volume fraction (φc) and the imaginary component (σmi = iωεoεmr) below φo are shown to have the correct power law dispersion behavior, but only if the non-universal exponents measured in previously described DC experiments are used. It is also shown that all the results can be scaled, as is predicted by percolation theory, so as to lie on two continuous curves, one below and one above φc. Unfortunately the actual ωc values used to scale the experimental results are found not to be in good agreement with theoretical predictions.

Type
Research Article
Copyright
Copyright © Materials Research Society 1998

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References

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