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∼400 pC/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.