Bending Vibrator Consisting of a LiNbO₃ Plate with a Ferroelectric Inversion Layer

Abstract

An anti-polarity ferroelectric laminar domain (inversion layer) can be formed in a LiNbO 3 plate without applying any external fields by heat treatment at somewhat lower temperatures than the Curie point. A plate with such an inversion layer can be used as a bending vibrator with no bonding layer. This paper reports the characteristics of the bending vibrators. The 137° rotated Y -cut of LiNbO 3 is shown to be the optimum plate orientation for the bending vibrators because it exhibits a high transverse electromechanical coupling factor of about 0.51. It is also demonstrated that a bending vibrator fabricated using 128° rotated Y -cut LiNbO 3 has a capacitance ratio as low as 7.82, which is slightly higher than the theoretically predicted value.