**2.8 Sodium niobate (NaNbO3)**

This is also the member of perovskite family, but with anti ferroelctric properties. Six phase transition in between −200 to 650°C range affects its structural, dielectric, and optical properties. Phase transition at 200,360 and 480°C has been observed due to off center displacement of Nb ion with tilting of oxygen octahedral. Its stable cubic structure of the *Pm3m* space group has been observed at high temperature, i.e. >640°C [127, 128]. The orthorhombic structure of the phase *Pbcm* space group has been observed at room temperature is antiferroelctric one. At 360°C the antiferroelcetric orthombic structure with *Pbma* space group undergoes phase transition to antiferroelectric orthorhombic structure with a *Pnmm* space group associated with maximum dielectric constant [129–134]. NaNbO3 single crystal exhibit low-frequency relaxation processes [135]. Distinct discontinuity is observed in mean relaxation time and relaxation parameter at Curie temperature Tc. At high temperature, low frequency relaxation increases due to crystalline structure disorder. This leads formation of local dipole in the polar region [136]. Stimulating electrical and mechanical properties of Sodium niobate-based ceramics make them a useful candidate for many technological applications [136–147]. At attainable electric fields this well-known antiferroelectric shows FE properties. Cost effective lead-free nanowire based NaNbO3 piezoelectric has a high-output [148]. So it find application in hologram and optical data storage having high density [137–143]. It also used as nanocapacitors, NGs and in the memories of nanoscale [148–150]. For large-scale lead-free piezoelectric NG may be NaNbO3 nanowires is one of useful candidate [151].

**39**

**Author details**

Paramjit Kour1

Patna, Bihar, India

\* and Sudipta Kishore Pradhan<sup>2</sup>

\*Address all correspondence to: paramjit.kour@bitmesra.ac.in

provided the original work is properly cited.

1 Department of Physics, Birla Institute of Technology, Patna, Bihar, India

2 Department of Mechanical Engineering, Birla Institute of Technology,

© 2021 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

*Perovskite Ferroelectric*

**3. Conclusions**

*DOI: http://dx.doi.org/10.5772/intechopen.98382*

Several reports on ferroelectric materials and their use for different piezoelectric application has been studied in the last few years. As discussed in this chapter the effect of perovskite structure affect its ferroelectric properties. Doping in these perovskite structures also responsible for the enhanced of its properties by tailoring its crystal structure. These materials now investigated in the composite, nanowire and the nanorods form to make the device mechanically robust and more compact.

This is a vital field for the research, as a key element in the digital world.
