Dielectric properties of 65PMN-35PT/P(VDF-TrFE) 0-3 composites

Lead magnesium niobate-lead titanate (PMN-PT with 35 mol.% PT) single crystal powder has been incorporated into a polyvinylidene fluoride-trifluoroethylene (P(VDF-TrFE) 70/30 mol.%) copolymer matrix to form 0-3 composites. With 65/35 mol.% composition, PMN-PT has high piezoelectric properties as a result of the enhanced polarizability arising from the coupling between two equivalent energy states. P(VDF-TrFE) ferroelectric copolymer films can be poled to give piezoelectric and pyroelectric performance without prior mechanical stretching. The composites were prepared using solvent casting to disperse the single crystal powder homogeneously in the matrix. Composites with PMN-PT volume fraction phi ranging from 0.05 to 0.4 were fabricated using a hot-press method. The relative perinittivity and pyroelectric coefficients of the composites were measured as a function of phi. Good agreement has been obtained between the theoretical and experimental values. Under the same poling condition, the composites have higher pyroelectric coefficient than the pure copolymer films. Hysteresis measurements reveal that the remanent polarization of composites increases as phi increases. (C) 2002 Published by Elsevier Science B.V.