Gamma irradiation induced dielectric modulation and dynamic memory in nematic liquid crystal materials

Abstract Present studies investigate the effect of gamma irradiation in the dielectric and electro-optical properties of a nematic liquid crystal (NLC) 4 cyano-4′-pentylbiphenyl (also referred to as 5CB) at the room temperature using the dielectric spectroscopy and the polarizing optical microscopic techniques. The value of dielectric permittivity (e′) of 5CB modulates with the cumulative doses of gamma irradiation because of the generation of free radicals and ions. It has also been observed that the relaxation frequencies of 5CB are found to shift towards the higher frequency side with the increase in the effective dose of the gamma rays. Further, non-volatile memory of short duration is found to be induced in 5CB upon the gamma irradiation which is absent in the pristine 5CB. These results will pave the way to fabricate various memory devices based upon NLCs with the desired dielectric and electro-optical parameters by tuning the dose of gamma irradiations.