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 (d/sub 33/ > 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 d/sub 33/. The hydrostatic piezoelectric coefficient d/sub h/ was also measured and the d/sub 31/ coefficient was calculated by d/sub 31/ = (d/sub h/ - d/sub 33/)/2.