Top-Seeded Solution Growth and Properties of K1–xNaxNbO3 Crystals

A series of large-sized (maximum 16 × 16 × 20 mm 3 ), high-quality K 1– x Na x NbO 3 ( x = 0.118, 0.378, 0.462, 0.545, and 0.666) single crystals were successfully cultivated using the top-seeded solution growth method. The crystallization and structures of the K 1– x Na x NbO 3 single crystals were studied using first-principles calculations and X-ray diffraction, respectively. The segregation of the K 1– x Na x NbO 3 single crystals was investigated, which enabled precise control of the individual components of the crystals during growth. Excellent properties were obtained without annealing, including a low dielectric loss (minimum 0.2%), a saturated hysteresis loop with a low coercive field E c, a large piezoelectric coefficient d 33 ( d 33 = 161 pC/N when x = 0.378), and a low leakage current density J (10 –6 A/cm 2 ). These results indicated that the K 1– x Na x NbO 3 ( x = 0.118, 0.378, 0.462, 0.545, and 0.666) crystals can be used as a high-quality, lead-free piezoelectric material.