Temperature dependence of piezoelectric coefficients of 0.71 Pb(Mg Nb )O0.29 PbTiO₃ piezoelectric single crystals

Abstract
Piezoelectrically induced displacements were measured by the laser interferometry method for multidomain-engineered 0.71 Pb(Mg_{1 / 3}Nb_{2 / 3}) O₃-0.29 PbTiO₃ single crystals in the temperature range 260 K-333 K. It was confirmed that this single crystal has large piezoelectric coefficients if the poling is done along the [001]-direction. Assuming an effective tetragonal symmetry, we determined the piezoelectric d₃₁ coefficient by measuring the displacement on (100) and (110) crystal faces. Coefficient d₃₁ = - 611 pC/N was calculated for the [100]-direction at room temperature. Its value is higher at 330 K (-820 pC/N). Piezoelectric coefficient d₃₁ measured on a second sample in the [110]-direction exhibited a higher value than the previous one, about -808 pC/N at room temperature, -1180 pC/N at 331 K and -605 pC/N at 262 K. Temperature dependencies of piezoelectric coefficient d₃₃ were also investigated. The second sample exhibits about 15% higher d₃₃ than the first one -1598 pC/N and 1390 pC/N at RT. This difference is 50% -2355 pC/N and 1600 pC/N at 331 K.