Temperature dependence of the damping constant and the relaxation time close to the tetragonal-cubic phase transition in SrZrO3

• Tetragonal-cubic phase transition in SrZrO3 is studied.
• Damping constant and the relaxation time are calculated for SrZrO3 using two models.
• They are fitted to the experimental data fom the lterature.
• Activation energy is extracted from the damping constant of soft modes in SrZrO3.
• Calculations explain the observed behavior of SrZrO3 near TC.

The damping constant Γsp due to the pseudospin-phonon coupling is calculated as a function of temperature using the pseudospin-phonon coupled model and the energy fluctuation model close to the tetragonal-cubic transition (TC = 1443 K) in SrZrO3. Using the observed Raman frequencies and the linewidth (FWHM) of the soft modes (Eg and A1g) from the literature, predictions of both models studied, are examined for the tetragonal-cubic transition in this crystalline system. Values of the activation energy U are extracted and also the inverse relaxation time is predicted as a function of temperature close to the phase transition studied in SrZrO3.Divergence behaviour of the damping constant (FWHM) of the soft modes is predicted from both models as also observed experimentally when TC is approached from the tetragonal to the cubic phase in SrZrO3. The relaxation time also diverges close to the TC in this crystal. It is indicated that the tetragonal-cubic transition is of a second order as predicted from both models studied here, as also observed experimentally in SrZrO3.