Dielectric Relaxation and Electrical Properties of Lead-Free LiNbO_3-Substituted Na_(0.5)K_(0.5)NbO_3 Ferroelectric Ceramics

摘要

Na_(0.5)K_(0.5)NbO_3 ceramics and LiNbO_3-substituted Na_(0.5)K_(0.5)NbO_3 ceramics were prepared by the solid-state reaction method. The crystallization and grain morphology of the two types of ceramics were confirmed by X-ray diffraction and atomic force microscopy studies, respectively. The 5 mol% LiNbO_3 substituted Na_(0.5)K_(0.5)NbO_3 ceramics shows well-saturated ferroelectric P-E hysteresis loops. The dielectric and electrical properties of the ceramics were investigated in the frequency range from 10 Hz to 1 MHz and the temperature range from 25℃ to 600℃. Analysis of the complex impedance relaxation by the Cole-Cole plot showed one impedance relaxation for LiNbO_3 substituted Na_(0.5)K_(0.5)NbO_3. The contributions of electrical conduction in the above mentioned temperature and frequency ranges are discussed.