E) curves of the seed, matrix, and composite were measured at 0.1 Hz, as shown in Fig. [6(a,b)](#Fig6){ref-type="fig"}. Room-temperature strain (bipolar and unipolar curves) for the ST26 composite with the seed ST10 were obtained for different soaking times. The P-E loop of the t-ST26-ST10 composite shows a pinched-type curve with a decrease in the remnant polarization (P~r~ from 9.7 to 8.7 µC/cm^2^) and coercive field (E~c~ from 1 to 0.4 kV/cm) due to the change from a ferroelectric to relaxor nature. The opposite trends were also observed and were more prominent in the r-ST26-ST10 composite (P~r~ from 7.3 to 14.4 µC/cm^2^ and E~c~ from 0.4 to 1 kV/cm). However, the saturation polarizations were almost the same as the soaking time increased for both types of seed content. In the case of bipolar strain, maximum strain (S~max~) of 0.30% and 0.26% were achieved at 40 kV/cm for t-ST26-ST10 and r-ST26-ST10 composites sintered for 4 h. Overall, the field-induced strain tends to decrease with increasing the soaking time. The increase in the soaking time accelerates the phase transformation from short-range ordering RF phase to long-range ordering FE phase or vice versa. Under a unipolar strain, the minimum triggering field required to achieve the high strain is 25--30 kV/cm. A large dynamic normalized strain (d~33~\*) is achieved in case of t-ST26-ST10 with \~890 pm/V and r-ST26-ST10 with \~700 pm/V at 40 kV/cm with soaking time of 4 h. The highest unipolar d~33~\* is attained in t-ST26-ST10 (\~890 pm/V) at soaking time of 4 h, while in r-ST26-ST10 (\~775 pm/V) at soaking time of 12 h. With the further increasing soaking time, the negative strain also increased due to the absorption of the seed into the matrix, resulting in a homogenous solution and the disappearance of the core-shell structure, as shown in Fig. [2](#Fig2){ref-type="fig"}. The d~33~, d~33~\*, and S~max~ values of the seed, matrix, and composite are shown in Fig. [7(a,b)](#Fig7){ref-type="fig"}. In the case of the t-ST26