Piezoelectric coefficients of PMN-0.33PT single crystals

Lead magnesium niobate doped with 33 mol% lead titanate (PMN-0.33PT) single crystals have high piezoelectric coefficients (d₃₃ > 2000 pC/N) and thus have good potential to be used as sensors, actuators and transducers for medical ultrasound. PMN-0.33PT crystals of diameter 30 mm and length 40 mm. long have been grown. A sample plate with its normal along the [001] axis was cut from the PMN-PT crystal and was poled along the thickness direction. A sinusoidal voltage was applied across the surfaces of the plate and an interferometer was used to measure the induced displacement in the thickness direction to give the piezoelectric coefficient d₃₃. The hydrostatic piezoelectric coefficient d_h was also measured and the d₃₁ coefficient was calculated by d ₃₁ = (d_h - d₃₃)/2