scholarly journals Critical behavior of the spontaneous polarization and the dielectric susceptibility close to the cubic-tetragonal transition in BaTiO3

2015 ◽  
Vol 05 (03) ◽  
pp. 1550024
Author(s):  
H. Yurtseven ◽  
F. Oğuz
Keyword(s):  
Critical Behavior ◽  
Critical Exponents ◽  
Spontaneous Polarization ◽  
Field Model ◽  
Mean Field ◽  
Dielectric Susceptibility ◽  
Mean Field Model ◽  
Temperature And Pressure ◽  
Quantum Limits

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 [Formula: see text]. From the analysis of the dielectric susceptibility and the spontaneous polarization, the critical exponents are deduced in the classical and quantum limits for [Formula: see text]. From the critical behavior of the dielectric susceptibility, the spontaneous polarization can be described for the ferroelectric–paraelectric (cubic to tetragonal) transition between 4 and 8 GPa at constant temperatures of 0 to 200 K in [Formula: see text] within the Landau mean field model given here.

scholarly journals Analysis of the Dielectric Constant as a Function of Temperature at Constant Electric Fields for the Smectic A-Smectic G Transition in A6

2012 ◽  
Vol 2012 ◽  
pp. 1-5
Author(s):  
H. Yurtseven ◽  
E. Kilit
Keyword(s):  
Dielectric Constant ◽  
Electric Fields ◽  
Field Model ◽  
Mean Field ◽  
Dielectric Susceptibility ◽  
Ferroelectric Liquid Crystal ◽  
Mean Field Model ◽  
Smectic A ◽  
Observed Behaviour ◽  
The Mean

The temperature dependence of the dielectric constant is studied under some fixed electric fields for the smectic G- (tilted-) smectic A (orthogonal) transition of the ferroelectric liquid crystal of compound A6. For this study, a mean field model with the quadrupole-quadrupole interactions is introduced. By fitting the inverse dielectric susceptibility from the mean field model to the experimental data from the literature, the observed behaviour of the dielectric constant is described satisfactorily for the smectic AG transition in A6. The transition temperature induced by an external electric field is also discussed for this ferroelectric compound.

scholarly journals Statistics of Dislocation Slip Avalanches in Nanosized Single Crystals Show Tuned Critical Behavior Predicted by a Simple Mean Field Model

2012 ◽  
Vol 109 (9) ◽  
Author(s):  
Nir Friedman ◽  
Andrew T. Jennings ◽  
Georgios Tsekenis ◽  
Ju-Young Kim ◽  
Molei Tao ◽  
...  
Keyword(s):  
Single Crystals ◽  
Critical Behavior ◽  
Field Model ◽  
Mean Field ◽  
Dislocation Slip ◽  
Mean Field Model

Calculation of the Spontaneous Polarization and the Dielectric Constant for the Ferroelectric N(CH3)4HSO4 Using the Mean Field Model

2017 ◽  
Vol 36 (9) ◽  
pp. 863-869
Author(s):  
H. Yurtseven ◽  
M. Celik ◽  
H. Karacali
Keyword(s):  
Experimental Data ◽  
Dielectric Constant ◽  
Spontaneous Polarization ◽  
Field Model ◽  
Mean Field ◽  
Mean Field Model ◽  
Temperature Dependences ◽  
Inverse Susceptibility ◽  
The Mean ◽  
Fitting Parameters

AbstractThe temperature dependences of the spontaneous polarization and the dielectric constant (susceptibility) are calculated using the mean field model for the ferroelectric N(CH3)4HSO4. Expressions derived from the mean field model for the spontaneous polarization and the inverse susceptibility are fitted to the experimental data from the literature. The fitting parameters in the expansion of the free energy in terms of the spontaneous polarization are determined within the temperature intervals in the ferroelectric and paraelectric phases of N(CH3)4HSO4. Our results show that the temperature dependences of the spontaneous polarization and the dielectric constant as predicted from our mean field model, describe adequately the observed behavior of N(CH3)4HSO4 in the ferroelectric and paraelectric phases.

scholarly journals On the Singularity of the Liquid-Gas Coexistence Curve Diameter

2020 ◽  
Vol 65 (9) ◽  
pp. 802
Author(s):  
O. Bakai ◽  
M. Bratchenko ◽  
S. Dyuldya
Keyword(s):  
Field Model ◽  
Mean Field ◽  
Power Series Expansion ◽  
Coexistence Curve ◽  
Mean Field Model ◽  
The Mean ◽  
Temperature And Pressure ◽  
Complete Scaling ◽  
Asymmetry Parameters ◽  
Reduced Temperature

A simplified Anisimov–Wang variant of the complete scaling approach makes it possible to determine the amplitudes of singularities for the diameter of the phase coexistence curve (CXC) on the basis of the coefficients in the power series expansion of the mean-field free energy in the reduced temperature and pressure near the critical point. This method is applied to obtain the amplitudes for the leading critical singularities of the CXC diameter in the case of a fluid described in the framework of the mesoscopic mean-field model. The results obtained demonstrate that the amplitudes of leading singularities of the CXC diameter are determined by the mesoscopic asymmetry parameters of the heterophase fluid.

scholarly journals Revisiting a low-dimensional model with short range interactions and mean field critical behavior

2021 ◽  
Author(s):  
Peter Grassberger
Keyword(s):  
Critical Exponents ◽  
Field Model ◽  
Mean Field ◽  
Dimensional Model ◽  
Mean Field Model ◽  
Small Deviations ◽  
Dimensional Version ◽  
Low Dimensional ◽  
2D And 3D ◽  
Non Equilibrium

Abstract In all local low-dimensional models, scaling at critical points deviates from mean field behavior – with one possible exception. This exceptional model with “ordinary” behavior is an inherently non-equilibrium model studied some time ago by H.-M. Bröker and myself. In simulations, its 2-dimensional version suggested that two critical exponents were mean-field, while a third one showed very small deviations. Moreover, the numerics agreed almost perfectly with an explicit mean field model. In the present paper we present simulations with much higher statistics, both for 2d and 3d. In both cases we find that the deviations of all critical exponents from their mean field values are non-leading corrections, and that the scaling is precisely of mean field type. As in the original paper, we propose that the mechanism for this is “confusion”, a strong randomization of the phases of feed-backs that can occur in non-equilibrium systems.

scholarly journals Quark mean-field model for single and double   and   hypernuclei

2014 ◽  
Vol 2014 (1) ◽  
pp. 13D02-0 ◽  
Author(s):  
J. N. Hu ◽  
A. Li ◽  
H. Shen ◽  
H. Toki
Keyword(s):  
Field Model ◽  
Mean Field ◽  
Mean Field Model

EVOLUTION OF SHELL STRUCTURE IN NUCLEI

2011 ◽  
Vol 20 (08) ◽  
pp. 1663-1675 ◽  
Author(s):  
A. BHAGWAT ◽  
Y. K. GAMBHIR
Keyword(s):  
Shell Structure ◽  
Crucial Role ◽  
Field Model ◽  
Mean Field ◽  
Mass Region ◽  
The Other ◽  
Mean Field Model ◽  
Relativistic Mean Field ◽  
Shell Closures ◽  
Low Mass

Systematic investigations of the pairing and two-neutron separation energies which play a crucial role in the evolution of shell structure in nuclei, are carried out within the framework of relativistic mean-field model. The shell closures are found to be robust, as expected, up to the lead region. New shell closures appear in low mass region. In the superheavy region, on the other hand, it is found that the shell closures are not as robust, and they depend on the particular combinations of neutron and proton numbers. Effect of deformation on the shell structure is found to be marginal.

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