Czochralski growth of potassium lithium niobate single crystals with low Li content and their characterization

Single crystalline and crack free potassium lithium niobate (KLN) single cr ystals with low Li content were grown by the Czochralski method. The crysta l composition can be written as K2.60Li1.17Nb5.44O15 (=K2.95Li1.33Nb6.17O17 ) which contain relatively fewer Li ions than ferroelectric K3Li2Nb5O15 cry stals. Ail experimental results show that the deficiency of the Li ions in the KLN crystals strongly influences their physical properties. Especially, the as-grown crystals do not indicate any signature for a ferroelectric ph ase transition in contrast to the ferroelectric K3Li2Nb5O15 crystals. Howev er, due to ionic conduction, the temperature dependence of the dielectric c onstant of such KLN-2 crystals show a broad anomaly near 300 degreesC. in a ddition, the existence of proton defects can be revealed by infrared absorp tion spectroscopy near 3500 cm(-1) in as-grown crystals.