**Acknowledgements**

**4. Future scope and implications**

128 Ferroelectrics and Their Applications

based piezoelectric materials.

converse piezoelectric constant *d*<sup>33</sup>

The lead-free Ba0.7Ca0.3Ti1−xSnx

**5. Conclusions**

The search of lead-free piezoelectric ceramics has significantly improved over the last two decades. The deep research in ferroelectric materials can develop better ferroelectric and electrostrictive ceramics. It is necessary to develop lead free ceramic materials having morphotropic phase boundary like PZT and improve the temperature dependence of piezoelectric properties of lead free ceramics. Lower Curie temperature of BT based ceramics hinders their use in practical applications. Improvement in this regime is most welcome in the future. The improvement in piezoelectric properties of BT based ceramics has done in last few years which are attractive for various applications; though need to improve other basic properties such as Curie temperature and temperature dependent piezoelectric properties to accelerate the use of BT based materials in piezoelectric applications. It is difficult to replace the PZT by single lead free piezoelectric material. Therefore, need to develop different lead-free materials which can fulfill the different challenges and can useful for various piezoelectric applications. The BT based polycrystalline electroceramics possess inferior properties than BT based single crystal materials. In future this gap can be fulfilled by textured piezoceramics. The textured piezoelectric ceramics have potential to fulfill the gap between polycrystalline and single crystal piezoelectric ceramics. In conventional polycrystalline ceramics grains are randomly oriented while in the textured polycrystalline ceramics grain structure is oriented along one of the crystallographic direction. Due to the orientation of grain structure in specific crystallographic direction, the textured piezoelectric materials give higher performance characteristics close to single crystal materials. Also, as compare to single crystal materials the textured polycrystalline ceramics do not suffer from fracture toughness issues. In future textured BT based piezoelectric materials can become potential materials to replace the lead

We have successfully developed the superior quality high dense microstructure BaTiO<sup>3</sup>

BT exhibits the saturation and remnant polarization of Psat. = 24.13 μC/cm2

O3

electroceramic material with *c/a* axial ratio of ~1.0144 having an average grain size ~7.8 μm. The

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%,

troceramic system showed the maximum electrostrictive coefficient (*Q33*) value of 0.0667 m<sup>4</sup>

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

<sup>∗</sup> ~376.35 pm/V and electrostrictive coefficient Q33~ 0.03493 m4

(*x* = 0.00, 0.025, 0.050, 0.075, and 0.1, abbreviated as BCST) elec-

RCK thankfully acknowledge the Science and Engineering Research Board (SERB)-DST, Government of India (File No. EMR/2016/001750) for providing the research funds under Extra Mural Research Funding (Individual Centric) scheme.
