Intrinsic and extrinsic electric response in Bi0.5Na0.5TiO3- BaTiO3 lead-free piezoceramics

(Bi0.5Na0.5)TiO3-BaTiO3 (BNT-BT) lead-free piezoelectric ceramics with compositions near the rhombohedral-tetragonal morphotropic phase boundary (MPB) have been prepared and investigated. In this work, the best properties was observed in BNT-0.07BT, with the piezoelectric coefficient d(33) and the planar electromechanical coupling factor k(p) being 151 pC/N and 0.278, respectively. The dielectric response of the poled (Bi0.5Na0.5)TiO3-xBaTiO(3) ceramics were investigated as a function of composition and temperature using Rayleigh analysis, dielectric Rayleigh coefficient alpha and initial dielectric constant epsilon(init) increase with x increasing, and has a substantial increase in the tetragonal phase. Detailed analysis of the temperature dependence of alpha and epsilon(init) curves of all compositions revealed different temperature in the maximum value due to the dominate contributions of domain wall motion.