Dielectric and piezoelectric anisotropy of lithium niobate and lithium tantalate single crystals

摘要

The dielectric and piezoelectric coefficients of lithium niobate (LiNbO3) and lithium tantalite (LiTaO3) single crystals have been theoretically calculated and experimentally measured for different cutting orientation directions. For LiNbO3 and LiTaO3, the measured effective dielectric ε33 and piezoelectric d33 exhibit the same trend with the calculated ones in YOZ plane. Their longitudinal piezoelectric coefficient d33 can be enhanced greatly near 60° direction canted away from the [111] rhombohedral direction. The enhancement of longitudinal piezoelectric coefficient d33 along a nonpolar direction can be understood as a consequence of the large shear piezoelectric coefficients.