**6. Conclusion**

The present chapter describes the fundamental understanding of normal ferroelectrics to relaxor ferroelectrics and its possible applications in the modern technologies. The intriguing properties of relaxor ferroelectrics originate due to the presence of polar nano regions as a result of compositional fluctuation at the crystal structure. Although there are several theories available to explain the origin and dynamic of PNRs with external stimulus, it needs to establish the proper structure-properties relation for relaxor ferroelectrics. As per the material aspect, lead-based materials are dominating in the current markets. Therefore, the design of new lead-free relaxor ferroelectrics with enhanced physical properties is required for future applications.

#### **Acknowledgements**

Ths work was supported by Indian Institute of Technology Patna (IIT Patna).

### **Conflict of interest**

The authors declare no conflict of interest.
