Magnetic field effects on the electric modulus properties of nematic mixture E7

Abstract

The molecular dynamics of the homogeneously aligned nematic liquid crystal mixture E7 subject to a magnetic field has been studied. The dielectric spectra study has revealed a low bias magnetic field effect on the evolution of dielectric relaxation spectra occurred at lower (∼kHz) (δ-relaxation) and higher (∼MHz) (α-relaxation) frequency regions. The complex electric modulus, which converted from experimental dielectric spectra, has been analyzed with theoretical model of Debye relaxation. The obtained fitting parameters of relaxation time and strength of dielectric components are shown to vary systematically with the strength of applied magnetic field. A microscopic molecular dynamic model has been proposed to describe the two-step variation of E7 molecular under the bias magnetic field. The results provide implication for magneto-modulation of liquid crystal molecular dynamics under the bias magnetic field.