Growth of Incipient Ferroelectric KTaO3 Single Crystals by a Modified Self-Flux Solution Method

High-quality potassium tantalate (KTaO3, KT) single crystals are grown by a high-temperature self-flux solution modified method in which potassium carbonate (K2CO3) and boron oxide (B2O3) are utilized as a complex flux. Additions of small amounts of boron oxide, used because of its low melting temperature (450 °C) and tendency to decrease the weight losses, increased the metastable region, requiring lower temperature (≤1300 °C) for the growth of relatively large KT crystals thereby suppressing the K volatilization tendency. By changing the flux composition and flux to solute proportion growth conditions are modified. The as-grown potassium tantalate crystals exhibit a dielectric permittivity of 6600 and dielectric losses of 0.004 at 13 K and 100 kHz. These results suggest a new promising approach for growing relatively large size and high quality single crystals within KT-based system.