Analysis of the α-β Transition in Bismuth Titanate as a Function of Pressure and Temperature

Abstract

The temperature and pressure dependence of the damping constant (half-width) for the soft Raman mode in bismuth titanate, Bi2Ti4O11, was calculated using the pseudospin-phonon coupled (PS) and the energy fluctuation (EF) models in the vicinity of the transition at T-C = 513 K and P-C = 3.7 GPa. The order parameter that is associated with the observed soft Raman mode frequency and also the pressure-temperature phase diagram was used for this calculation of the damping constant. Our calculated values of both the Raman frequency and the damping constant were compared with the observed data from the literature. Finally, the values of the activation energy were deduced using our calculated damping constant via the Arrhenius plots.