In this study, a method in which an electric field-induced phase transition in bismuth-based ceramics is used at a relatively low field of 40 kV/cm is proposed. This study investigated the electrical properties and electric field-induced strain of Bi_0.5Na_0.5TiO₃ (BNT) single particle-added Bi_0.5(Na_0.75K_0.25)_0.5TiO₃-BiAlO₃ (BNKT-BA) ceramics. Strains of 0.27% and 0.29%, for 0.94BNKT-0.06BA with 10% BNT and 0.93BNKT-0.07BA with 20% BNT, were observed, respectively. These strains were attributed to the transition from non-polar to ferroelectric phases in BNKT-BA small grains with ferroelectric BNT large grains during external electric field execution.

In this study, electromechanical characteristics of (1-x) Bi_0.5Na_0.5TiO₃–xSrTiO₃ (ST26, x = 0.26)/(1-y) Bi_0.5Na_0.5TiO₃–ySrTiO₃ (ST10, y = 0.1) (matrix/seed) composites were studied. The ST26 (high relaxor phase) and ST10 (a relaxor ferroelectric (RF), high ferroelectric phase) composite with large (r-ST26-ST10) and small (t-ST26-ST10) grains exhibited frequency-related dielectric properties and large strain response at a low triggering electric field (an incipient piezoelectricity). It is ascribed to a matrix-seed effect originating from the inhomogeneous composition due to the presence of two phases. The r-ST26-ST10 composite sintered at 4 h, prominent material, showed a high normalized dynamic strain (d₃₃*) of ~700 pm/V (large grains) with stable frequency dependence properties at a low field of 40 kV/cm. The properties of the r-ST26-ST10 composite exhibit less decay with frequency-related polarization and strain compared to those of t-ST26-ST10 composite. The increase in soaking time promotes the diffusion and homogenization of the microstructure in composites, leading to changes in the core-shell structure in the solid solution. The polarization and strain of the ST26-ST10 composites with the frequency are linked to the stability of the internal random fields created by non-ergodic relaxor phase of seed and the amount of phase change in the ergodic relaxor matrix.