Strain properties of (1-x)Bi0.5Na0.4K0.1TiO3-xBi(Mg2/3Ta1/3)O3 electroceramics
© 2020 Elsevier Ltd and Techna Group S.r.l. A ternary solid solution of Bi0.5Na0.5TiO3–Bi0.5K0.5TiO3–Bi(Mg2/3Ta1/3)O3 (BNKT-xBMT) lead-free electroceramics was synthesized by a solid-state reactive sintering technique. The electrostrain, dielectric, and ferroelectric properties as well as the impedance characteristics and the microstructure were systematically assessed. With the increase of BMT, the BNKT-xBMT ceramics gradually transformed from non-ergodic relaxor phase to ergodic relaxor phase, manifested as the ferroelectric-to-relaxor temperature (TF-R) shifts towards below room temperature. Additionally, the ferroelectric hysteresis curves became pinched, and the strain curve changed from butterfly-shaped into sprout-shaped. At the ergodic relaxor composition of x = 0.04, a large electrostrain value (S = 0.4%; under an electric field of 60 kV/cm, d33* = 632 pm/V) was achieved, which is mainly attributed to the electric-field-induced transition from the ergodic relaxor phase to the ferroelectric phase.