Investigation of the radial extensional mode of ln piezoelectric crystal

Piezoelectric materials functional at elevated temperatures without failure are desirable for various piezoelectric applications. In this paper, the lithium niobate (LiNbO
₃
, LN) crystal and the radial extensional (RE) properties were studied. Based on the crystal symmetry, the equations to evaluate the k
_p
value with Z- and Y-oriented discs were deduced. Using the deduced equations, the k
_p
values of the Z-oriented and Y-oriented LN crystal discs were calculated and obtained to be 3.83% and 24.7%, respectively. In addition, the radial extension mode was studied experimentally by impedance method, where the k
_p
values were found to be on the order of 3.80% and 24.5%, respectively. Moreover, the temperature dependence of RE electromechanical properties were investigated from room temperature to 500°C, where the variation of the k
_p
was found to be <;8% for the Y-oriented discs. The large k
_p
value and minimal temperature dependent behavior of Y-oriented crystal cuts indicating the potential uses for high temperature piezoelectric application.