Pressure dependence of the piezoelectric polarization of LiNbO 3 and LiTaO 3

Linear and nonlinear hydrostatic piezoelectric constants for lithium niobate and lithium tantalate are determined from measurements of the hydrostatic piezoelectric polarization at pressures from 0.05 GPa to 2.6 GPa. The nonlinear constants are found to be large and relatively easy to detect. In LiTaO3 the nonlinear constant is large enough to reduce the piezoelectric coefficient to zero in the vicinity of 2.2 GPa. The nonlinear constants are interpreted in terms of the pressure dependence of the electrostrictive constants. The linear constant measurements indicate that LiNbO3 should prove useful for a wide variety of piezoelectric stress transducers for impulsive loading measurements.