Effective complex permittivity of random composite media PVDF / 0.5(Ba0.7Ca0.3)TiO3-0.5Ba(Zr0.2Ti0.8)O3: A comparative study

Lead-free nanoceramic powder of a morphotropic phase boundary composition 0.50(Ba0.7Ca0.3)TiO3– 0.50Ba(Zr0.2Ti0.8)O3 (BCZT50) was prepared by utilizing solid-state synthesis route followed by high-energy ball milling. The ceramic-polymer nanocomposites (1-x)PVDF/xBCZT50; x=0.025, 0.05, 0.10, 0.15, 0.20, 0.25 were fabricated utilizing a melt-mixing technique. The real and imaginary parts of complex permittivity displayed an increasing trend of variation with the increasing filler concentration. Five dielectric mixture equations for the high volume fractions of the filler material in the mixture have been tested to see their acceptability. It was observed that equations given by Bruggeman, Rother-Lichtenecker, and Knott showed their consistency with the experimental results of real and imaginary parts of complex permittivity for all the chosen test materials over the entire range of measurements of volume fractions.