Electrical tunability of a composite consisting of small ferroelectric spheres randomly dispersed into a dielectric background is studied. A new method to calculate the effective permittivity of such a nonlinear composite is introduced. The method is based on the Bruggeman effective medium theory and a specific model for the nonlinear permittivity of the ferrite. The resulting tunability (defined as a measure of the change in the permittivity due to the bias field) is a continuous function of the volume fraction of the ferroelectric material phase in the composite. As an example,SrTiO3 is studied with two different nontunable background materials.
"Tunability of Granular Ferroelectric Dielectric Composites," ,
Vol. 78, 189-207, 2008. doi:10.2528/PIER07081502
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