Complete set of material constants of single domain (K, Na)(Nb, Ta)O3 single crystal and their orientation dependence

Abstract

A self-consistent complete set of dielectric, piezoelectric, and elastic constants for single domain Ta modified (K, Na)NbO₃ (KNN) crystal was determined. This full set constant for single domain KNN-based crystals allowed the prediction of orientation dependence of the longitudinal dielectric, piezoelectric, elastic coefficients, and electromechanical coupling factors. The maximum piezoelectric and electromechanical properties were found to exist near [001] _<i>C</i> . In addition, material constants of [001] _<i>C</i> poled domain engineered single crystal with 4 mm symmetry were experimentally measured and compared with the calculated values. Based on this, extrinsic contribution to the piezoelectricity was estimated to be ∼20%.