Critical behaviour of the dielectric constant for the smectic AC* transition under the electric field in ferroelectric liquid crystals

Date

2012-01-01

Author

Yurtseven, Hasan Hamit

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

240
views

0
downloads

The temperature dependencies of the dielectric constant and the tilt angle (order parameter) are calculated under the electric field for the smectic A-smectic C* (AC*) transition in 4-(3-methyl-2-chlorobutanoyloxy)-4'-heptyloxybiphenyl (A7). The dielectric constant is fitted to the experimental data by using our mean field model with the biquadratic coupling between the spontaneous polarisation P and the tilt angle theta. Our results show that the mean field model with the P-2 theta(2) coupling describes satisfactorily the observed behaviour of the AC* transition in A7. It is indicated here that a first-order AC* transition occurring at low electric fields changes its character towards a second order as the electric field increases in A7.

Subject Keywords

Dielectric constant, Order parameter

URI

https://hdl.handle.net/11511/39439

Journal

PHYSICS AND CHEMISTRY OF LIQUIDS

DOI

https://doi.org/10.1080/00319104.2011.651209

Collections

Department of Physics, Article

Suggestions

OpenMETU
Core

Calculation of the damping constant and the order parameter for the lattice mode in ferroelectric PbTiO3 Kiraci, A.; Yurtseven, Hasan Hamit (2013-07-25) The temperature dependences of the damping constant and the order parameter are calculated for the lattice mode of E (1TO) in PbTiO3 using the experimental data by the pseudospin- phonon coupled model and the enrgy fluctuation model. Calculation of the damping constant of soft mode is performed in the temperature range of 400- 490 degrees C close to the ferroelectric- paraelectric transition (T-C= 493 degrees C) in PbTiO3. By relating the frequency to the order parameter, the temperature dependence of the R...
Temperature dependence of the polarization, dielectric constant, damping constant and the relaxation time close to the ferroelectric-paraelectric phase transition in LiNbO3 Kiraci, A.; Yurtseven, Hasan Hamit (2017-01-01) We calculate the order parameter (spontaneous polarization) and the inverse dielectric susceptibility at various temperatures in the ferroelectric phase of LiNbO3 for its ferroelectric-paraelectric phase transition (T-C =1260 K) using the Landau phenomenological model. For this calculation, the Raman frequencies of the soft optic mode (TO1) are used as the order parameter and the fitting procedure is employed for both the order parameter and the inverse dielectric susceptibility by means of the observed dat...
A First-Order Transition of the Smectic A-Smectic C* in Ferroelectric Liquid Crystals Kilit, E.; Yurtseven, Hasan Hamit (2012-01-01) The static dielectric constant is calculated as a function of temperature using a mean field model close to the smectic A-smectic C* transition for the ferroelectric liquid crystal 4-(3-methyl-2-chlorobutanoyloxy)-4'-heptyloxybiphenyl (A7). This calculation of the dielectric constant is performed for the pure optically active compound (T-c = 73.4 degrees C) and the temperature range is determined for a first-order smectic A-smectic C* transition from the mean field model. Our predicted values describe adequ...
Calculation of the Dielectric Constant of a Ferroelectric Liquid Crystal From a Mean Field Model YURTSEVEN, HASAN HAMİT; Yurtseven, Hasan Hamit (2011-01-01) The static dielectric constant epsilon(perpendicular to) of the ferroelectric liquid crystal 4-(3-methyl-2-chlorobutanoyloxy)-4'--heptyloxybiphenyl (A7) with high spontaneous polarization is calculated as a function of temperature using a mean field model. This calculation is performed close to the smectic A-isotropic liquid (SmA-I) transition for pure optically active compound (T-c = 81.6 degrees C). For this calculation of epsilon(perpendicular to), the free energy of the SmA phase is expanded in terms of...
Spontaneous polarization close to phase transitions in NaNO2 Yurtseven, Hasan Hamit; Tari, O (2001-08-01) We give here the calculation of the order parameter and the spontaneous polarization as functions of temperature using the mean field model close to the phase transitions in NaNO2. We have fitted our calculated order parameter to the observed one from the literature. From this fitting, we have then calculated the spontaneous polarization as a function of temperature close to the phase transitions in NaNO2. Our calculated spontaneous polarization is in good agreement with the observed spontaneous polarizatio...

Citation Formats

H. H. Yurtseven, “Critical behaviour of the dielectric constant for the smectic AC* transition under the electric field in ferroelectric liquid crystals,” PHYSICS AND CHEMISTRY OF LIQUIDS, pp. 367–377, 2012, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/39439.