Growth of potassium lithium niobate-tantalate single crystal for piezoelectric applications

(K,Li)NbO₃ single crystals were successfully grown from a melt with potassium enriched composition under the condition of shallow temperature gradient using the TSSG technique. The growth was along the <100> direction in the pseudo-cubic phase. The crystal was allowed to grow laterally from around 10-30h to obtain the cross section desired. The growing crystal was then lifted up above the melt surface or lifted intermittently at the rate of about 4mm/h, while the melt was cooled. Cracking occurred at the phase transition temperatures of 457 and 220°C for (K,Li)NbO₃. Slow cooling fairly eliminated the cracking at the both phase transition points. The completeness of the poling was checked by the dielectric measurements. After poling, the dielectric constant reduced to be around 150.