High strain in (K_0.40Na_0.60)(Nb_0.955Sb_0.045)O₃-Bi_0.50Na_0.50ZrO₃ lead-free ceramics with large piezoelectricity

We have attained both large piezoelectricity and high strain in (1 - x)(K_0.40Na_0.60)(Nb_0.955Sb_0.045)O₃-xBi_0.50Na_0.50ZrO₃ [(1 - x)KNNS-xBNZ] lead-free ceramics by forming a rhombohedral (R) and tetragonal (T) phase boundary. The ceramics with 0.035 < x < 0.05 possess R and T phases' coexistence. A large d₃₃ value of ∼450 pC N^-1 has been attained when the x value reached 0.04 owing to the involved R-T phase boundary, which is higher with respect to d₃₃ ∼ 416 pC N^-1 of textured (K,Na,Li)(Nb,Ta,Sb)O₃ ceramics reported by Saito et al. [Nature, 2004, 432, 84]. In addition, it is worth noting that such a ceramic simultaneously possesses a high electric field-induced strain (0.2%) under a low driving electric field of ∼2 kV mm^-1, and its S_max/E_max value is equal to be 1071 pm V^-1. As a result, we can believe that the (1 - x)KNNS-xBNZ ceramics will become one of the promising material systems in the practical applications of electrical devices.