Electric field dependent attenuation constant in BaxSr1xTiO3 perovskites

Abstract

A theoretical expression is derived for attenuation constant in para-electric phase in anharmonic BaxSr1xTiO3 ferroelectric crystal, using double time temperature dependent Green’s function technique. Taking electric field as a parameter, the variation of attenuation constant with frequency and temperature has been studied by considering third and fourth order anharmonic interactions. The mass and force constant change due to the presence of impurity atoms in Silverman-Joseph Hamiltonian augmented with higher order anharmonic terms. The effect of electric field, defect and anharmonicity on stabilization of the soft mode frequency has also been studied. The attenuation constant increases with increasing temperature and frequency in the presence of an electric field. In the vicinity of the Curie temperature, the attenuation constant increases anomalously.