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.

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.

The mean field model withP2θ2coupling for the smectic A-smectic C* phase transition in liquid crystals

1998 ◽  
Vol 66 (1-4) ◽  
pp. 259-270 ◽  
Author(s):  
S. SalihoĞLu ◽  
H. Yurtseven ◽  
A. Giz ◽  
D. Kayişoğlu ◽  
A. Konu
Keyword(s):  
Phase Transition ◽  
Liquid Crystals ◽  
Field Model ◽  
Mean Field ◽  
Mean Field Model ◽  
Smectic A ◽  
Smectic C ◽  
The Mean

Single-Crystal Magnetic Properties of [Co(NH3)5(OH2)] [Cr(CN)6] Between 2 and 300 K

1992 ◽  
Vol 45 (11) ◽  
pp. 1899 ◽  
Author(s):  
PA Reynolds ◽  
CD Delfs ◽  
BN Figgis ◽  
B Moubaraki ◽  
KS Murray
Keyword(s):  
Ising Model ◽  
Field Model ◽  
Mean Field ◽  
Zero Field ◽  
Spin Orbit Coupling ◽  
Zero Field Splitting ◽  
Magnetic Exchange Interaction ◽  
Mean Field Model ◽  
Magnetic Exchange ◽  
The Mean

The magnetic susceptibilities along and perpendicular to the c axis (hexagonal setting) between 2.0 and 300 K at a magnetic field of 1.00 T, and the magnetizations at field strengths up to 5.00 T, are presented for single crystals of [Co(NH3)5(OH2)] [Cr(CN)6]. The results are interpreted in terms of zero-field splitting (2D) of the ground 4A2g term by spin-orbit coupling and of magnetic exchange interaction between the chromium atoms. The magnetic exchange is modelled as one of Ising or mean-field in type. The exchange is found to be quite small: J = -0.18(6) cm-1 if the Ising model is employed, and -0.03(1) cm-1 for the mean-field model. The model adopted for the exchange has a strong influence on the value of the parameter D obtained. When the Ising model is used D is deduced to be -0.28(9) cm-l; when the mean-field model is used D is -0.14(4) cm-l. The g-values deduced are in agreement with those from e.s.r. measurements at higher temperatures and do not depend on the exchange model. In any case, D is found to be sufficiently large that it must be considered in a polarized neutron diffraction experiment on the compound.

scholarly journals Phase diagram of the mean field model of simplicial gravity

1999 ◽  
Vol 542 (1-2) ◽  
pp. 413-424 ◽  
Author(s):  
P. Bialas ◽  
Z. Burda ◽  
D. Johnston
Keyword(s):  
Phase Diagram ◽  
Field Model ◽  
Mean Field ◽  
Mean Field Model ◽  
The Mean
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