Interferometric measurement of the temperature dependence of piezoelectric coefficients for PZN-8%PT single crystals

Piezoelectrically induced displacements were measured by a laser interferometric method in the temperature range 150 K-333 K for two domain-engineered 0.92Pb(Zn1/3Nb2/3)-0.08PbTiO(3) single crystals poled in the [001]-direction. Assuming an effective tetragonal symmetry, we determined the piezoelectric d(31) coefficient by measuring the displacement on (100) and (110) crystal faces. Coefficient d(31)=-1280 pC/N was calculated for the [100]-direction at room temperature. Its value is reduced to -550 pC/N at 210 K. Piezoelectric coefficient d 31 measured on a second sample in the [110]-direction exhibited a smaller value than the previous one, only about -555 pC/N at room temperature and -360 pC/N at 190 K. Different domain structures in both samples might be the possible reason for this difference. Temperature dependence of piezoelectric coefficient d(33) was also investigated. The effect of aging is also discussed. The domain configuration in crystals was observed by optical microscopy.