The effective medium approximations: Some recent developments

✍ Scribed by D. Stroud

• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 116 KB
• Volume: 23
• Category: Article
• ISSN: 0749-6036
• DOI: 10.1006/spmi.1997.0524

✦ Synopsis

We provide a brief and highly selective review of the Landauer-Bruggeman effectivemedium approximation as applied to random composite media. We first discuss this approximation as applied to linear composites, i.e., to those materials in which there is a linear relation between a curl-free electric field and a divergence-free current density. We then describe extensions of this approach to random composites with cubic nonlinearities in addition to a dominant linear term, and to composites in which the components have a fluctuating conductivity ('conductivity noise'). Finally, we mention one novel application: to conductivity noise in a random composite of normal metal (N ) and perfect conductor (S). It is shown that the extension of the EMA leads to a prediction of a frequency range in which the conductivity noise has a 1/ω frequency dependence, even if the noise in the individual components is frequency independent.