**5. Conclusions**

We have successfully developed the superior quality high dense microstructure BaTiO<sup>3</sup> (BT) electroceramic material with *c/a* axial ratio of ~1.0144 having an average grain size ~7.8 μm. The BT exhibits the saturation and remnant polarization of Psat. = 24.13 μC/cm2 and Pr = 10.42 μC/cm2 respectively with lower coercive field of E<sup>c</sup> = 2.047 kV/cm, which is good for ferroelectric memory device applications. The concept of peaking characteristics of the polarization current densityelectric field measurement is introduced to evidences the saturation state of polarization for most of the ferroelectric materials. The pure BT ceramics possesses the "sprout" shape nature instead of typical "butterfly loop" for strain-electric field measurements with remnant strain ~ 0.212%, converse piezoelectric constant *d*<sup>33</sup> <sup>∗</sup> ~376.35 pm/V and electrostrictive coefficient Q33~ 0.03493 m4 /C2 . The lead-free Ba0.7Ca0.3Ti1−xSnx O3 (*x* = 0.00, 0.025, 0.050, 0.075, and 0.1, abbreviated as BCST) electroceramic system showed the maximum electrostrictive coefficient (*Q33*) value of 0.0667 m<sup>4</sup> /C2 for *x* = 0.075 and it is higher than some of the significant lead based electrostrictive materials. From BCST system the compositions *x* = 0.05 and 0.075 showed the notable electrostrictive properties that may be useful for piezoelectric Ac device applications. For (1−x) BCST-xBCZT ceramics with x = 0.00, 0.25, 0.50, 0.75, and 1 we are successful to push the polymorphic phase transition temperatures (PPT) close to room temperature by Ca2+, Sn4+ and Zr4+ substitution for BT system. For BCST-BCZT system the composition x = 0.75 exhibits the d33, *d*<sup>33</sup> <sup>∗</sup> and *Q33* values of 310 pC/N, 385 pm/V and 0.089 m4 /C2 respectively which is greater than BT ceramics. Thus, the piezoelectric and ferroelectric properties of BT ceramic can significantly tune by Ca2+ and Sn4+, Zr4+ substitutions useful for electromechanical device application in future. Still there is a scope for BT based ceramics with Ca2+ and Sn4+, Zr4+ substitutions to achieve the morphotropic phase boundary composition having giant piezoelectric properties.
