Summary

A dielectric material is characterized by parameters such as dielectric constant or dielectric permittivity which is greater than 1. Other parameters which define dielectric beahviour are dielectric susceptibility and polarization where the former shows the response of a dielectric material upon application of electric field. Polarization in dielectrics happens because of variety of reasons and is a frequency dependent phenomenon as characterized by electronic, ionic and dipolar or orientation polarizations. Application of an alternating field on real dielectrics results in real and imaginary part of dielectric constant and in a loss tangent which define the quality of a dielectric. Frequency dependence of dielectric constant is also characterized by the presence of resonance phenomenon for electronic and ionic polarization mechanisms, occurring at frequencies typically above 10¹² Hz and relaxation phenomenon for orientation or dipolar polarization in polar materials which is a typically low frequency mechanism. The frequency dependence can also be modeled by impedance spectroscopy and Cole-Cole plots which give an insight into various relaxation mechanisms in a dielectric material arising due to various microstructural features.