Calculation of the Raman frequency and the damping constant of a coupled mode in the ferroelectric and paraelectric phases in KH(2)PO(4)

Date

2010-04-01

Author

KARACALİ, HUSEYİN
Kiraci, A.
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

201
views

0
downloads

The Raman frequency of the coupled mode omega_ associated with the order parameter is calculated as a function of pressure from the mean field theory in the ferroelecric phase of KDP. Using the frequencies of the coupled mode, the pressure dependence of the damping constant Gamma_ is calculated by the proton spin lattice relaxation time and by the energy fluctuation of this mode of KDP in the ferroelectric (FE) phase. For the paraelectric (PE) phase, the Raman frequency of the coupled mode omega is calculated as a function of temperature at 6.54 kbar. The temperature dependence of the damping constant Gamma_ is performed only by the energy fluctuation of the coupled mode omega_ in the PE phase of KDP. The values of the activation energy U are extracted from the pressure and temperature dependence of the damping constant Gamma_ of this coupled mode omega_ for both FE and PE phase of KDP. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Subject Keywords

Electronic, Optical and Magnetic Materials, Condensed Matter Physics

URI

https://hdl.handle.net/11511/40764

Journal

PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS

DOI

https://doi.org/10.1002/pssb.200945181

Collections

Department of Physics, Article

Suggestions

OpenMETU
Core

Calculation of the Infrared Frequencies as a Function of Temperature Using the Volume Data in the Ferroelectric Phase of NaNO2 Yurtseven, Hasan Hamit (Informa UK Limited, 2014-02-17) We calculate the temperature dependence of the infrared frequencies of the TO and LO modes with the symmetries of A(1), B-1 and B-2 mainly in the ferroelectric phase of NaNO2. This calculation is carried out using the volume dependence of the infrared frequencies through the mode Gruneisen parameter in this crystal. The volume dependences of the infrared frequencies are fitted to the observed frequencies by using constant mode Gruneisen parameter in the ferroelectric phase of NaNO2. Our results show that th...
Analysis of the Spontaneous Polarization and the Dielectric Constant Near the Ferroelectric Phase Transition in TSCC Yurtseven, Hasan Hamit (Informa UK Limited, 2008-01-01) The temperature dependence of the spontaneous polarization and the dielectric constant has been analyzed for the fixed pressures of 0.001,1 and 2.2 kbar close to the phase transitions in TSCC. This analysis is performed using the experimental data for TSCC according to a power-law formula. From our analysis, using the experimental data for the spontaneous polarization, we deduce the values of the critical exponent = 0.32 (1 bar), 0.28 (1 kbar) and 0.26 (2.2 kbar) for the spontaneous polarization near the tr...
Calculation of the T-P Phase Diagrams for the Halogenomethane Compounds (CCl4-nBrn, n=0, 1, 2, 4) Using the Mean Field Theory Yurtseven, Hasan Hamit; Dogan, E. Kilit (Pleiades Publishing Ltd, 2019-02-01) The T-P phase diagrams of the halogenomethane compounds (CCl4-nBrn, n = 0, 1, 2, 4) are calculated using a mean field model. By expanding the free energy in terms of the order parameters for the transitions of the liquid (L), rhombohedral (R), face-centered cubic (FCC) and monoclinic (M) phases in those compounds, the phase line equations are derived and they are fitted to the experimental data from the literature. This method of calculating the T-P phase diagram is satisfactory to explain the T-P measureme...
Damping constant and the inverse relaxation time calculated as a function of pressure using the X-ray diffraction data close to the cubic-tetragonal phase transition in SrTiO3 Yurtseven, Hasan Hamit (Informa UK Limited, 2019-10-01) The damping constant is calculated as a function of pressure at room temperature using the normalized intensity as an order parameter near the cubic-tetragonal phase transition in SrTiO3. The observed X-ray diffraction data are used for the normalized intensities to calculate the damping constant () from the pseudospin-phonon (PS) coupled model and the energy fluctuation (EF) model, which is fitted to the observed FWHM data from the literature for comparison. Using the calculated values, the pressure depend...
Calculation of the heat capacity Cp from the temperature-induced and pressure-induced Raman frequency shifts for solid benzene, naphthalene and anthracene Ozdemir, Hilal; Yurtseven, Hasan Hamit (Elsevier BV, 2019-02-01) The heat capacity Cp is calculated from the temperature-induced and pressure-induced Raman frequency shifts by means of the mode Griineisen parameter for the I-II transition of solid benzene, naphthalene and anthracene. For this calculation, contributions to Cp are considered due to the six lattice modes of solid benzene, six librational modes of naphthalene and, six phonons and nine vibrons of anthracene with their mode Griineisen parameters at various temperature (P = 0) and pressures (T=300 K). Our calcu...

Citation Formats

H. KARACALİ, A. Kiraci, and H. H. Yurtseven, “Calculation of the Raman frequency and the damping constant of a coupled mode in the ferroelectric and paraelectric phases in KH(2)PO(4),” PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS, pp. 927–936, 2010, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/40764.