High-quality K_0.47Na_0.53NbO₃ single crystal toward high performance transducer

A large-sized, high-quality single crystal of K_0.47Na_0.53NbO₃ was grown by the top-seeded solution growth method. A complete set of elastic, dielectric, and piezoelectric constants for a [001]_C-poled K_0.47Na_0.53NbO₃ single crystal was determined via combined resonance and ultrasonic methods. The [001]_C-poled K_0.47Na_0.53NbO₃ (KNN47) single crystal exhibits a large piezoelectric coefficient (d₃₃ = 220 pC N^-1), high coupling coefficients (k₃₃ = 0.759 and k_t = 0.702), high dielectric constants (ϵT11 = 2194 and ϵS11 = 2162), and relatively high elastic compliance constants (SE11 = 14.3 × 10^-12 N m^-2 and SE33 = 17.6 × 10^-12 N m^-2). Furthermore, a large electrical field induced strain of 0.16% was measured from the slope in the unipolar strain versus electric field dependence. The piezoelectric coefficient, was determined to be as high as 401 pm V^-1, likely resulting due to the morphotropic phase boundary around x = 0.5. These excellent properties make KNN47 a good candidate for application as a high-performance transducer material.