Low-temperature synthesis of lithium tantalate powders for single crystal growth

LiTaO3 (lithium tantalate) crystal is widely used in infrared detection, acoustic surface wave devices and optical applications due to its outstanding piezoelectric, pyroelectric, and nonlinear optical properties. Over the past few decades, LiTaO3 single crystals have been studied intensively for their excellent acoustic and electro-optical properties. For the single crystal growth of LiTaO₃, raw materials of Li₂CO₃ and Ta₂O₅ need to be pretreated to form LiTaO₃ polycrystal. However, high temperature, more than 1200 &deg;C and long heating time are required for adequate crystallization. <br/><br/> In this study, we prepared LiTaO₃ polycrystalline powder by solid state reaction synthesis from the raw powder of Li₂CO₃, Ta₂O₅, and cyanuric acid, which is an additive for a short reaction time and relatively low temperatures. The cyanuric acid, added into the mixture of Li₂CO₃ and Ta₂O₅, plays a role of fuel and inducer to produce intermediate compounds. Several temperatures and cyanuric acid composition ratio were employed to optimize the synthesis condition of pretreated LiTaO₃. Structural and composition analysis were conducted to characterize the synthesized LiTaO₃ powders. The optimized synthesis shows excellent ability to reduce lithium-ion volatilization and suggests an efficient way to manufacture high-quality LiTaO₃ polycrystalline powders.