Gamma-radiation-induced dielectric relaxation characteristics of layered crystals of phlogopite mica

• Phlogopite mica was used in the present investigation.
• Dielectric relaxation of gamma irradiated phlogopite mica was analyzed.
• The data have also been fitted with the Havriliak-Negami function.

In the present investigation, the influence of gamma irradiation on the dielectric relaxation characteristics of phlogopite mica was studied over the frequency range of 0.1 Hz–10 MHz and in the temperature range of 593–813 K by measuring the dielectric permittivity, electric modulus and conductivity. By comparing the dielectric spectra obtained for pristine and irradiated samples, it was observed that gamma irradiation significantly enhances the dielectric constants (ε′ and ε″) of phlogopite mica because of the production of defects and lattice disorder by the gamma irradiation. The values of the activation energy for pristine and irradiated mica (determined from the electric modulus and the conductivity) were found to be substantially similar, suggesting that the same types of charge carriers are involved in the relaxation mechanism. The experimentally measured electric modulus and conductivity data could be well interpreted by the Havriliak–Negami dielectric relaxation function. The scaling of the electric-modulus spectra of both pristine and irradiated mica results in a master curve, which indicates that the relaxation mechanism is independent of temperature. Cole–Cole plots were also employed to analyze the non-Debye relaxation mechanism. This research will boost the reader’s interest concerning the emerging contributions of irradiation and materials such as mica in electrical engineering.