Growth of lithium doped silver niobate single crystals and their piezoelectric properties

Lithium doped silver niobate (Ag1-xLixNbO3, 0 < x < 0.1) is one of the candidate materials for lead-free piezoelectric materials. In this study, Ag1-xLixNbO3 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 degrees C was shifted to lower temperature while the phase transition at around 400 degrees C was shifted to higher temperature. On the basis of these peak shifts, the lithium contents in Ag1-xLixNbO3 single crystals were determined. Moreover, P-E hysteresis measurement revealed that pure silver niobate crystal was weak ferroelectrics with P-r of 0.095 mu C/cm(2) while Ag0.9Li0.1NbO3 (ALN10) crystal was normal ferroelectrics with P-r of 10.68 mu C/cm(2). About this ALN10 crystal, polling treatment was performed and finally piezoelectric properties were measured. As a result, high electromechanical coupling coefficient k(31) over 70% was observed. (c) 2005 Elsevier B.V. All rights reserved.