Thermodynamic and bias field investigation of an antiferroelectric liquid crystal

Dielectric spectroscopy of an antiferroelectric liquid crystal material (S)-4-(1-methylheptyloxycarbonyl)phenyl-4′-(6-pentanoyloxyhex-1-oxy)biphenyl-4-carboxylate 4H6Bi(S) for its helical phases has been carried out under bias electric field in the frequency range 0.1 Hz-10 MHz. Bias field investigation has been carried out in order to explore new relaxation modes. Dielectric characterization of the material, when carried out as a function of DC bias, reveals soft mode around 350 kHz and domain mode at ∼100 Hz in the SmC⁎ phase as a consequence of suppression of Goldstone mode due to helix unwinding. In the SmC⁎A phase a field induced new relaxation mode has been investigated at 8.0 kV/cm having relaxation frequency from 100 Hz to 600 Hz with increasing bias electric field.