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

Abstract

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 ($\mathrm{\Gamma }$) 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 $\mathrm{\Gamma }$ values, the pressure dependence of the inverse relaxation time (${\tau }^{-1}$) is predicted close to the cubic-tetragonal phase transition in SrTiO₃. Our calculated damping constant from both models explains the observed FWHM satisfactorily and our prediction of the inverse relaxation time can also be compared with the experimental measurements when they are available in the literature.

Keywords:

• Damping constant
• inverse relaxation time
• X-ray diffraction intensity
• cubic-tetragonal transition. SrTiO3