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

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](C). In addition, material constants of [001](C) poled domain engineered single crystal with 4mm symmetry were experimentally measured and compared with the calculated values. Based on this, extrinsic contribution to the piezoelectricity was estimated to be similar to 20%. (C) 2014 AIP Publishing LLC.