The electromechanical features of LiNbO3 crystal for potential high temperature piezoelectric applications

Lithium niobate (LiNbO3, LN) crystal is a multi-functional material with favorable piezoelectric, nonlinear optical and electro-optic properties. In this study, the electromechanical properties of the radial extensional (RE) and the thickness extensional (TE) modes of the congruent LN are studied and the temperature dependent behaviors are revealed. The RE mode electromechanical coupling factors (kp) for the Y- and Z-oriented discs are calculated and found to be 3.8% and 24.7%, respectively, which are nearly the same as the experimental results of 3.8% and 25.2%, respectively. The maximum RE and thickness shear (TS) modes electromechanical coupling factors are obtained to be 47.6% and 68.5% for the Yx/25° and Yx/167° crystal cuts, respectively. The LN crystal possesses good temperature stability of the electromechanical coupling factors (RE and TE modes) from 20 °C to 500 °C, where the variations of kp and kt for the Y-oriented discs are