Temperature dependence of the polarization, dielectric constant, damping constant and the relaxation time close to the ferroelectric-paraelectric phase transition in LiNbO3

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 data from the literature. The temperature dependences of the damping constant and the inverse relaxation time are also computed using the pseudospin-phonon coupled model and the energy fluctuation model for the ferroelectric phase of LiNbO3. The activation energy is deduced from the damping constant for both models studied and compared with the k(B)T(C) value of LiNbO3.

Suggestions

Critical behaviour of the dielectric constant for the smectic AC* transition under the electric field in ferroelectric liquid crystals
Yurtseven, Hasan Hamit (2012-01-01)
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 sa...
Temperature Dependence of the Spontaneous Polarization and the Dielectric Susceptibility near the Phase Transitions in Ammonium Sulfate
Sen, S.; Yurtseven, Hasan Hamit; Kavruk, D. (2010-01-01)
Spontaneous polarization and the dielectric susceptibility are calculated as a function of temperature close to the paraelectric-ferroelectric phase transition (T-C=223 K) in (NH4)(2)SO4 This calculation is performed using a mean field model by fitting the expressions derived for the dielectric susceptibility to the experimental data for the dielectric constant at the fixed frequencies of 100, 500 and 2000 Hz in ammonium sulfate
Critical behavior of the spontaneous polarization and the dielectric susceptibility close to the cubic-tetragonal transition in BaTiO3
Yurtseven, Hasan Hamit (2015-09-01)
Using Landau mean field model, the spontaneous polarization and the dielectric susceptibility are analyzed as functions of temperature and pressure close to the cubic-tetragonal (ferroelectric-paraelectric) transition in BaTiO3. From the analysis of the dielectric susceptibility and the spontaneous polarization, the critical exponents are deduced in the classical and quantum limits for BaTiO3. From the critical behavior of the dielectric susceptibility, the spontaneous polarization can be described for the ...
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 Raman Frequency, Damping Constant and the Activation Energy of a Soft-Optic Mode in Ferroelectric Barium Titanate
Kiraci, A.; Yurtseven, Hasan Hamit (2012-01-01)
The Raman frequency of a soft-optic mode associated with the order parameter is calculated as a function of temperature from the mean field theory for barium titanate (T-C = 222K). Using the Raman frequencies calculated, the damping constant is evaluated and it is compared with the observed one for this soft-optic mode.
Citation Formats
A. Kiraci and H. H. Yurtseven, “Temperature dependence of the polarization, dielectric constant, damping constant and the relaxation time close to the ferroelectric-paraelectric phase transition in LiNbO3,” OPTIK, pp. 183–191, 2017, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/33240.