Bridgman Growth of Large-size and Compositionally Uniform Relaxor Ferroelectric PMN-PT Crystals

Relaxor ferroelectric single crystal, PMN-PT, has great potential to be an innovative piezoelectric material in both actuator and transducer applications. Large-size PMN-PT single crystals with diameter of 40-50mm have been successfully grown along different crystallographic directions, including < 111 >, < 110 > and < 001 >, by Bridgman technique at TRS Technologies. The current status of Bridgman growth will be presented with emphasis on the longitudinal and lateral uniformity of the differently oriented boules evaluated by composition analysis and properties characterization. In < 001 >-oriented Bridgman growth, very high lateral uniformity has been achieved with the maximum variation in a whole (001) wafer less than +/- 4% for both piezoelectric coefficient and dielectric constant, which show the significant advantage of < 001 >-oriented growth.