Debye type dielectric relaxation in carbon nano-balls' and 4-DMAABCA acid doped E7 coded nematic liquid crystal

Abstract

The electrical properties of carbon nano-balls' and 4-dimethylaminoazobenzene-2'-carboxylic acid doped dispersed nematic liquid crystal composite were investigated by impedance spectroscopy technique. The conductivity and capacitance were measured in the frequency range 100 kHz-1 MHz and temperature range 300-380 K. The loss peak was observed in the dielectric loss spectra and was identified as nearly-Debye type relaxation. Cole-Cole plots have been used to describe the characteristic changes of electrical properties in mentioned temperature interval. The sample presents monodispersive relaxation behavior with a relaxation time of similar to 10(-7) s. The relaxation process is attributed to the dipolar rotation of the long molecular axis and the activation energy is found to be 0.097 eV. (C) 2008 Elsevier B.V. All rights reserved.