Crystallographically engineered BaTiO3 single crystals for high-performance piezoelectrics

Abstract

Dielectric and piezoelectric properties of BaTiO3 single crystals polarized along the 〈001〉 crystallographic axes were investigated as a function of temperature and dc bias. Electromechanical coupling (k33)≃85% and piezoelectric coefficients (d33)≃500 pC/N, better or comparable to those of lead-based Pb(Zr,Ti)O3 (PZT), were found from 〈001〉-oriented orthorhombic crystals at 0°C, as a result of crystallographic engineering. A rhombohedral BaTiO3 crystal polarized along 〈001〉 also exhibited enhanced piezoelectric performance, i.e., k33≃79% and d33≃400pC/N at -90°C, superior to PZTs at the same temperature. It was found that the crystal structure determined the (in)stability of the engineered domain state in BaTiO3 single crystals. Rhombohedral (3m) crystals at -100°C exhibited a stable domain configuration, whereas depoling occurred in crystals in the adjacent orthorhombic phase upon removal of the E field. © 1999 American Institute of Physics.