Dielectric and pyroelectric properties of BaTiO 3 –PVC composites

Dielectric relaxation and pyroelectric response of the barium titanate–poly (vinyl chloride) BaTiO 3 –PVC composites of 0–3 connectivity and volume fraction of ceramics ϕ from 0.0 to 0.4 were investigated. Dielectric properties of the composites were found to be a combination of those of pure PVC polymer and BaTiO 3 ceramics: the value of dielectric permittivity increases with increasing volume fraction of the ceramics but the temperature dependence is determined by two relaxation processes in the polymer (at ∼270 K – the local motion of the small groups in the chain and at ∼350 K – the segmental molecular motion) and in the ceramics (dielectric anomaly at the phase transitions). The value of the pyroelectric coefficient p of poled composites increases with ϕ and depends on the light modulation frequency f m as p ∼ f – n m with n ≈ 0.9 to 1.1, dependently on ϕ . (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)