Growth of silver lithium niobate single crystals and their piezoelectric properties

Silver lithium niobate (Ag_1-xLi_xNbO₃, 01-xLi_xNbO₃ single crystals were successfully grown by a slow cooling method. Crystal structure was assigned to perovskite-type orthorhombic (monoclinic) phase. Dielectric properties were measured as a function of temperature. As a result, with increasing lithium contents, the phase transition at around 60°C was shifted to lower temperature while the phase transition at around 400°C was shifted to higher temperature. On the basis of these peak shifts, the lithium contents in Ag_1-xLi_xNbO₃ single crystals were determined. Moreover, P-E hysteresis measurement revealed that pure silver niobate crystal was a weak ferroelectric with Pr of 0.095 μC/cm² while Ag_0.9Li_0.1NbO₃ (ALN10) crystal was normal ferroelectrics with Pr of 10.68 μC/cm². About this ALN10 crystal, polling treatment was performed and finally piezoelectric properties were measured. As a result, high electromechanical coupling coefficient k₃₁ over 70% was observed.