Dear Dr Madan Lal ,

welcome!

Cole-Cole plots can be made at any specific temperature.

It reflects how the real and imaginary dielectric constant depend on the frequency of the applied electric field. The shape of the curves themselves depend on the type of polarization.

The Curie temperature is that temperature at which the material begins to loose its ferro electric properties.

After loosing the ferroelectric properties the permanent dipoles will be randomly oriented and the polarization type will be the orientation polarization.

Please see the lecture notes:Book properties of dielectric materials BY abdelhalim zekry

Best wishes

Dear Dr. Lal

Both Nyquist and Cole-Cole plots were used to calibrate semiconducting nature of the material under study. The critical temperature has important role to define magnetic properties in the sample. Therefore, after Tc almost magnetic properties died out............

thank you

Respected S. K. Parida sir and Abdelhalim abdelnaby Zekry sir I am agree with both answers and grateful to you for your reply.

Dear Parida,

There exist a direct relation between the dielectric constant, which is tightly relation to the polarization mechanism in the dielectric material, and its crystal structure (e.g., cubic, hexagonal,..etc). In general, there exist 3 basic types of electric polarization sources in a dielectric solid material, namely: electronic, ionic and dipolar. However, both ionic and dipolar polarizations depend on the crystal structure. Most of ionic crystals are cubic and hence have ionic polarization. Also, the ferroelectric materials, which show spontaneous electrical polarization (below Tc), have a crystal direction-dependent polarization. In addition, the unit cell of Cubic lattices lacks a center of inversion and don't show piezoelecric polarization (pressure-induced polarization).