Second order dielectric permittivity of PT/P(VDF-TrFE) 0-3 composites

For a fundamental understanding of a composite material comprising two ferroelectrics and also with respect to applications, it is important to know the degree of poling in the two constituent phases. The second order dielectric permittivity of 0-3 composites of lead titanate (PT) and vinylidene fluoride-trifluoroethylene (PVDF-TrFE), with various volume fractions of the ceramic phase, is reported. Composites with only the ceramic phase polarized, i.e. poled at temperature above the Curie temperature of the copolymer and below the Curie temperature of the ceramics, and composites with both the ceramic and the copolymer phases polarized have been studied. The experimental results have been analyzed with a model of ferroelectric cuboides embedded in a ferroelectric matrix. The contributions of the ceramic and copolymer phases to the second order permittivity have been separated, thereby giving the degree of poling in each of the two phases.