Magnetic and Dielectric Properties of Materials Consisting of Oriented,Iron Flake Filler within a Thermoplastic Host: Part II Transport Model Review and Evaluation

Abstract

Materials that contain both an electric permittivity and magnetic permeability greater than unity (magneto-dielectrics) are currently being investigated for microwave applications. Magneto-dielectric composite materials based upon flake-like iron inclusions were fabricated and the iron flakes oriented within a low loss thermoplastic host. The electrical and magnetic properties of the magneto-dielectric composites were predicted using mean field and effective medium approximations, as well as the Wu—McCullough generalized transport model. Predicted values were compared to measured properties as a function of the filler’s aspect ratio, surface characteristics and volume fraction. The Wu—McCullough model was found to be the most accurate in predicting the transport properties, but required an accurate description of the microstructure (flake aspect ratio and alignment).

Keywords

magneto-dielectric composite high-aspect ratio filler ferromagnetic flakes.

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