0.40% Bipolar Strain in Lead Free BNT–KNN System Modified with Li,Ta and Sb

In this work we demonstrate a large electric field‐induced bipolar strain ~0.40% in Li, Ta and Sb modified BNT–KNN ((1?x) Bi_0.5Na_0.5TiO₃–xK_0.47Na_0.47Li_0.06 Nb_0.74Sb_0.06Ta_0.2O₃) system. The morphotropic phase boundary (MPB) of the system between rhombohedral and tetragonal phases lies in the range 0.02 ≤ x ≤ 0.06, beyond which all compositions (up to x < 0.15) were found to be tetragonal. A clear trade‐off between the large strain values and achievable d₃₃, k_p for a particular composition was noted. It is shown that while for x = 0.03, d₃₃ 169 pC/N, k_p 49% and strain ~0.13% were obtained, for x = 0.08 with 0.40% strain, d₃₃ and k_p values decreased drastically.