Large electric-field induced strain in new ternary lead-free piezoelectric solid solution Na0.5Bi0.5TiO3-BaTiO3-Sr (Ta0.5Al0.5) O3

Ternary lead-free piezoelectric ceramics Na0.5Bi0.5TiO3-BaTiO3-Sr(Ta0.5Al0.5)O3 were synthesized via conventional solid-phase synthesis. All samples exhibited pure perovskite structure, indicating that Sr(Ta0.5Al0.5)O3 can be solidified into the Na0.5Bi0.5TiO3-BaTiO3 perovskite structure. The remanent polarization Pr and coercive field EC of the undoped Na0.5Bi0.5TiO3-BaTiO3 ceramic were Pr∼35.23µC/cm2 and EC∼42.46 kV/cm, respectively. The introduction of Sr(Ta0.5Al0.5)O3 sharply affected the ferroelectric properties of the substrate Na0.5Bi0.5TiO3-BaTiO3 ceramics. Increase in the content of Sr(Ta0.5Al0.5)O3 induces transition of this ternary system from a ferroelectric phase to an antiferroelectric-like phase, accompanied by double hysteresis loops in the 0.003SAT, 0.005SAT, and 0.01SAT components. The high dielectric constant ε′∼4300 was obtained for the 0.005SAT composition. The 0.015SAT composition yielded the maximum bipolar electric-field strain S (%) ∼0.53 % and high-field piezoelectric strain coefficient d33*∼ 996 pm/V. This result shows that a ternary Na0.5Bi0.5TiO3-BaTiO3-Sr(Ta0.5Al0.5)O3 solid solution is a promising alternative to lead-based piezoelectric materials in the field of high-performance actuators.