Enhancement in Dielectric Properties of Nematic Liquid Crystal by Gamma Irradiation

Abstract

A gamma irradiation technique has been used to alter the dielectric properties of a liquid crystal system. The present paper reports a comparative dielectric study of a gamma-irradiated and an unirradiated nematic liquid crystal. This study is an attempt to see the irradiation effect in the alignment and dielectric parameters of a nematic liquid crystal. The dielectric measurements have been done with the temperature variation in the frequency range 100 Hz to 10 MHz. The dielectric data show relaxation modes that follow Cole-Cole theory. The Cole-Cole plots have been used to determine the dielectric parameters such as relaxation frequency and relaxation strength. The dielectric permittivity is found to increase for the gamma-irradiated sample as compared with the unirradiated sample with variation in temperature and frequency and well explained in this paper.

Keywords:

• Dielectric parameter
• electrical conductivity
• gamma radiation
• relaxation frequency

Acknowledgments

The authors are thankful to BRNS India for financial assistance. One of the authors (AKM) is thankful to UGC, New Delhi, for the Dr. D. S. Kothari Post Doctoral Fellowship No.F.4.2/2006 (BSR)-13–234/2008(BSR). The authors are also thankful to Mr. T. K. Srinivasan for his help in gamma irradiation.