DIELECTRIC, PIEZOELECTRIC AND PYROELECTRIC RESPONSE OF PBTIO3-PVDF COMPOSITES

Dielectric, pyroelectric and piezoelectric properties of PVDF loaded w ith PbTiO3 ceramics of the mean grain size similar to 3 mu m were stud ied at room temperature. The low frequency dielectric absorption of co mposites with ceramic volume fraction x > 0.4 can be described by powe r epsilon '' similar to f(-n). The exponent n amounts tb about 1/2 in the frequency range 0.3 mHz-30 mHz and is about 1/3 at higher frequenc ies, i.e., 1 Ha to 10 kHz. In the MHz region the relaxation process, c haracteristic of the polymer, was overlapping with the dielectric abso rption characteristic of perovskites. Pyroelectric response was found to decrease with the light modulation frequency and the piezoelectric d(h) coefficient was observed do decrease slightly with pressure in th e range up to 60 MPa.