Calculation of the raman frequency, damping constant (Linewidth) and the relaxation time near the tetragonal-cubic transition in PbTiO3

Date

2017-01-01

Author

KİRACI, ALİ
Yurtseven, Hasan Hamit

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Frequencies, damping constants and the relaxation times of some Raman modes including the two soft modes are calculated as a function of pressure near the tetragonal-cubic transition in PbTiO3. Calculation of the Raman frequencies is performed using the observed volume data from the literature by means of the mode Gruneisen parameter at various pressures. Pressure dependence of the damping constant and the relaxation time is predicted using the pseudospin-phonon coupled model and the energy fluctuation model by considering that the Raman frequency can be taken as the order parameter (spontaneous polarization) for the tetragonal-cubic transition in PbTiO3. Expressions from both models for the damping constants are fitted to the observed Raman linewidths of the two soft modes and for the other Raman modes the damping constant and the relaxation time are predicted close to the transition. We find that damping constants diverge and the inverse relaxation time decreases for the soft modes with increasing pressure near the critical pressure (P-c similar to 11 GPa).

Subject Keywords

PbTiO3, Tetragonal-cubic transition, Relaxation time, Raman frequency, Damping constant

URI

https://hdl.handle.net/11511/40982

Journal

OPTIK

DOI

https://doi.org/10.1016/j.ijleo.2017.06.011

Collections

Department of Physics, Article

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Citation Formats

A. KİRACI and H. H. Yurtseven, “Calculation of the raman frequency, damping constant (Linewidth) and the relaxation time near the tetragonal-cubic transition in PbTiO3,” OPTIK, pp. 311–319, 2017, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/40982.