Dielectric and piezoelectric properties of lead-free 0.95(K_(0.5)Na_(0.5))NbO_3-0.05LiNbO_3 crystals grown by the Bridgman method

摘要

Lead-free potassium sodium niobate piezoelectric single crystals substituted with lithium 0.95(K_(0.5)Na_(0.5))NbO_3-0.05LiNbO_3 have been grown by Bridgman method and their dielectric and piezoelectric properties were studied. The orthorhombic-tetragonal and tetragonal-cubic phase transition temperatures of the single crystal appear at 192 and 426 ℃ according to the dielectric constant versus temperature loops, respectively, and the (001) plates show good piezoelectric properties with piezoelectric constant d_(33) as high as 405 pC/N, large thickness electromechanical coupling factor k_t = 61%, and low dielectric constant of 185 at room temperature. These excellent properties show that the 0.95(K_(0.5)Na_(0.5))NbO_3-0.05LiNbO_3 single crystal is a good lead-free piezoelectric material.