文摘
Solid-solution crystals play an increasing role in research and technology because their properties can be optimized by varying the concentration of their constituents for specific applications. Crystal morphology and size uniformity of cross-section are important factors to consider for obtaining high-quality crystals with excellent properties when crystals are grown by the top-seeded solution growth method. We propose effective energy models to explain the effects of growth temperature on the crystal morphology and size uniformity of KTa<sub>1–xsub>Nb<sub>xsub>O<sub>3sub> and K<sub>1–ysub>Na<sub>ysub>NbO<sub>3sub> single crystals, which are representative solid-solution crystals and have great application potential. Using the models, we could achieve the uniformity in size of cross-section by controlling the difference between growth temperature and equilibrium temperature. The as-grown KTa<sub>1–xsub>Nb<sub>xsub>O<sub>3sub> and K<sub>1–ysub>Na<sub>ysub>NbO<sub>3sub> single crystals with constant sizes of cross-section exhibited good crystallinities and had a large quadratic electro-optic coefficient s<sub>11sub> (s<sub>11sub> = 1.04 × 10<sup>–14sup> m<sup>2sup> V<sup>–2sup>) and a large piezoelectric coefficient d<sub>33sub> (d<sub>33sub> = 110 pC/N), respectively, indicating their high quality and suitability for device applications.