Temperature behaviour of the dielectric constant of tetragonal BaTiO₃

Abstract

Abstract A model is developed which assumes the temperature dependence of the dielectric constant of BaTiO 3 , along the ferroelectric axis in the tetragonal phase to be essentially determined by a relaxation mechanism involving dipole reorientation controled by tunneling across a double well potential barrier. Model parameters are determined from fits to existing data and it is shown that the fitted curves adjust well to the data within experimental error. The results support the hypothesis that the ferro‐to‐paraelectric transition in BaTiO 3 is not governed by phonon assisted processes but must be ascribed to an intrinsic type of disorder.