Electrical conductivity enhanced dielectric and piezoelectric properties of ferroelectric 0-3 composites

We have investigated the effects of electrical conductivity of the constituents on the dielectric and piezoelectric properties of ferroelectric 0-3 composites. The time-dependent internal electric fields are first derived, which can be induced by an applied ac field in dielectric measurement or stress in piezoelectric measurement. Our previously developed model fC. K. Wong, Y. M. Poon, and F. G. Shin, J. Appl. Phys. 90, 4690 s2001dg has been extended to include the additional contribution from the electrical conductivities and the frequency of measurement, which can be significant for ceramic/polymer composites possessing high conductivity in the matrix phase. The model provides an explanation to the surprisingly high piezoelectric d33 values reported by, e.g., Chen et al. fSens. Actuators, A 65, 194 s1998dg. Explicit expressions for the transient and steady-state responses are given and the effective permittivity, d33, d31, and dh coefficients have been derived. © 2005 American Institute of Physics. fDOI: 10.1063/1.1862317g