KNbO3 plate crystal grown by micro-pulling-down method from stoichiometric melt

Abstract Growth of plate potassium niobate (KNbO 3 ; KN) crystal from stoichiometric melt has been investigated by a micro-pulling-down (μ-PD) method. KN plate crystal with 1-2 mm×4-5 mm×35 mml dimensions was successfully grown using a platinum crucible with rectangular die of 4 mm×1 mm having a hole of 0.5 mm in diameter in its center. Obtained KN plate crystal did not contain K 4 Nb 6 O 17 phase, coexisting with the potassium niobate phase when crystallization follows the phase equilibrium diagram. It appeared that sufficient supercooling was attained during the growth, and that the potassium niobate phase was stabilized in the melt. The parameters necessary for the reproducible growth of KN plate crystal were associated with a solid–liquid interface during the growth. Phase transition temperatures of the grown plate crystal agreed well with previously reported data, and sharp transitions were observed.