The Proton Motion Effect in the Ferroelectric Phase of NH4H(ClCH2COO)2

1986 ◽  
Vol 41 (1-2) ◽  
pp. 286-289 ◽  
Author(s):  
Maria Zdanowska-Fraczek
Keyword(s):  
Order Parameter ◽  
Ferroelectric Phase ◽  
Spin Component ◽  
Applied Model ◽  
Spin Lattice ◽  
Coupled Mode ◽  
Line Splitting ◽  
Motion Effect

The effects of pressure up to 3 · 102 MPa on the 35Cl NQR line splitting in the ferroelectric phase of NH4H(ClCH2COO), was studied from 77 K to Tc. The results are interpreted in terms of the so called pseudo-spin-lattice coupled mode model. A correlation was found between the magnitude of the 35Cl NQR line splitting and the pseudo-spin component <S2> (the order parameter of the applied model).

scholarly journals Analysis of the integrated intensity of the central peaks calculated as a function of temperature in the ferroelectric phase of lithium tantalate

2018 ◽  
Vol 22 (Suppl. 1) ◽  
pp. 221-227
Author(s):  
Ali Kiracı ◽  
Hamit Yurtseven
Keyword(s):  
Order Parameter ◽  
Ferroelectric Phase ◽  
Brillouin Scattering ◽  
Dynamic Properties ◽  
Mean Field Theory ◽  
Mean Field ◽  
Central Peak ◽  
Academic Disciplines ◽  
Inverse Relaxation Time ◽  
Integrated Intensity

The integrated intensity of the central peak is calculated as a function of temperature in the ferroelectric phase (T < TC) of nearly stoichiometric LiTaO3. This calculation is performed using the temperature dependence of the order parameter obtained from the mean field theory at temperatures lower than the transition temperature TC (TC = 963 K) of this crystal. The calculated values of the order parameter (squared) are fitted to the integrated intensity of the central peaks as observed from the Raman and Brillouin scattering experiments as reported in the literature in the ferroelectric phase of nearly stoichiometric LiTaO3. Our results are in good agreement with the observed behavior of LiTaO3 crystal. Because of the applications of LiTaO3 in several academic disciplines including the material science and thermal science, it is beneficial to investigate dynamic properties of this crystal such as the damping constant, inverse relaxation time and the activation energy as also we studied here.

Phenomenological explanation of the anomalous dielectric behavior of alums with pseudo-spin-lattice coupled-mode model

1982 ◽  
Vol 26 (11) ◽  
pp. 6276-6284 ◽  
Author(s):  
K. R. Chaudhury ◽  
D. Nath ◽  
S. Banerjee ◽  
B. K. Chaudhuri
Keyword(s):  
Dielectric Behavior ◽  
Spin Lattice ◽  
Coupled Mode

scholarly journals CHANGES IN FERROELECTRIC PROPERTIES OF MASD ALUM ALONG WITH TEMPERATURE BY USING PLCM MODEL

2019 ◽  
Vol 14 (2) ◽  
Author(s):  
Anubhuti Mamgain ◽  
Trilok Chandra Upadhyay
Keyword(s):  
Ferroelectric Properties ◽  
Function Technique ◽  
Temperature Dependent ◽  
Spin Lattice ◽  
Coupled Mode ◽  
Dielectric Constant And Loss ◽  
Double Time ◽  
Anharmonic Interactions ◽  
Theoretical Results ◽  
Good Agreement

With addition of third-and fourth-order phonon anharmonic interactions, and extra spin-lattice interaction term into pseudospin-lattice coupled mode (PLCM) model, MASD alum has been studied. Employing double time temperature dependent Green′s function technique expressions for shift and width of response function, normal mode frequency, dielectric constant and loss stangent have been derived for MASD alum. Numerical calculation has been done. Theoretical results have been compared with experimental results of Pepinsky et al. [16]. A good agreement has been found.

scholarly journals Эффекты, связанные с ограниченной геометрией, в нанокомпозитах на основе мезопористых матриц 2D-SBA-15 и 3D-SBA-15, содержащих наночастицы нитрита натрия

2019 ◽  
Vol 89 (12) ◽  
pp. 1965
Author(s):  
А.А. Набережнов ◽  
Е.В. Стукова ◽  
О.А. Алексеева ◽  
С.А. Новикова ◽  
A. Franz
Keyword(s):  
Phase Transition ◽  
Sodium Nitrite ◽  
Order Parameter ◽  
Pore Diameter ◽  
Ferroelectric Phase ◽  
Average Pore Diameter ◽  
Temperature Hysteresis ◽  
Average Pore ◽  
Heating And Cooling ◽  
Temperature Dependences

The temperature dependences of the ferroelectric order parameter for nanostructured sodium nitrite on heating and cooling have been obtained from the analysis of the temperature evolution of diffraction spectra of neutron scattering on nanocomposites, produced by embedding of sodium nitrite into the pores of the mesoporous matrices 2D-SBA-15 (average pore diameter 69 (4) Å) and 3D-SBA-15 (average pore diameter 94 (5) Å ). It is shown that on heating the phase transition from the ferroelectric phase to the paraelectric one occurs at TC = 433 ± 1 K for both nanocomposite materials. The sizes of nanoparticles in both nanocomposites are determined and it is established that their size decreases on heating at approaching to the ferroelectric phase transition temperature. Temperature hysteresis (~ 15–20 K) have been found in the temperature dependence of the order parameter between heating and cooling regimes.

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