Polarization and Piezoelectric Properties of High Performance Bismuth Sodium Titanate Single Crystals Grown by High-Oxygen-Pressure Flux Method

(Bi0.5Na0.5)TiO3 (BNT) single crystals were grown by flux method at a high oxygen pressure (PO2) of 1 MPa, and their polarization and piezoelectric properties were investigated. BNT single crystals exhibited a saturated polarization hysteresis with remanent polarizations (P-r) of 31 mu C/cm(2) along [100](c), 44 mu C/cm(2) along [110](c) and 54 mC/cm(2) along [111](c). These results show that spontaneous polarization of BNT is approximately 55 mC/cm(2) or larger. Strain measurements of rhombohedral BNT crystals suggest that the polarization reversal along [111](c) is achieved by non-180 degrees P-s rotation whereas that along [100](c) is accomplished by 180 degrees Ps switching. (C) 2010 The Japan Society of Applied Physics