CRYSTAL-GROWTH AND ELECTRICAL-PROPERTIES OF PB((ZN1 3NB2/3)(0.91)TI-0.09)O-3 SINGLE-CRYSTALS PRODUCED BY SOLUTION BRIDGMAN METHOD/

Piezoelectric Pb((Zn1/3Nb2/3)(0.91)Ti-0.09)O-3 (PZNT 91/9) single crys tals 40 mm in diameter were successfully grown from solution by the Br idgman method with a PbO flux. The crystals were grown in a platinum c rucible heated to 1130 degrees C, Growth rate was 0.35 mm/h. The obtai ned crystals were similar to 40 mm in diameter x 20 mm in length and w ere a rust-brown color. The Curie temperature, T-C, ranged from 175 de grees to 185 degrees C, and the dielectric constant before poling at r oom temperature was 2000-8900 within a wafer. After electrical poling, specimens had electromechanical coupling coefficients in rectangular bar mode, k(33'), of 79%-88%, which were larger than for PZT ceramics (k(33') < 70%), These PZNT 91/9 single crystals grown by the Bridgman process satisfy the requirements for array-type transducers used in ec hocardiographic equipment. Results confirm that the Bridgman method is useful for mass-producing large crystals of PZNT 91/9.