Effect of sintering temperature on the growth of (K 0.5 Na 0.5 )NbO 3 single crystals fabricated by the solid-state crystal growth method

Abstract The effect of sintering temperature on the growth of (K 0.5 Na 0.5 )NbO 3 (KNN) single crystals fabricated by a solid-state crystal growth method with a sintering aid of 2 wt%Co 3 O 4 and the seed crystals of (110) and (100) KTaO 3 was investigated. For the KNN single crystals fabricated with the (110) KTaO 3 seed crystal, crystal growth length was gradually increased with increasing sintering temperature at the temperatures of 1020 °C–1120 °C. At the temperatures of 1130 °C–1200 °C, rapid growth was observed and a grown single crystal reached the surfaces of the ceramic compact containing the seed crystal. The length of the KNN crystal sintered at 1140 °C for 24 h was 690 μ m. On the other hand, such rapid growth was not observed for the KNN single crystals fabricated with the (100) KTaO 3 seed crystal. The length of the KNN crystal sintered at 1140 °C for 24 h was 160 μ m. The dielectric, ferroelectric, and piezoelectric properties of the KNN single crystal fabricated with the (110) KTaO 3 seed crystal at a sintering temperature of 1140 °C were reported.