Temperature-dependent hysteresis model for relaxor ferroelectrics

This paper addresses the development of a temperature- dependent constitutive model for relaxor ferroelectrics which is based on the assumption that the material is comprised of an aggregate of micropolar regions having a range of Curie temperatures. The diffuse transition behavior of the material is due to its chemical heterogeneity, and thermodynamic models for the microregions are developed by considering near neighbor interactions for varying cation ratios.. The result in micropolar model can be used to predict the saturation polarization and distribution of regions as a function of temperature. Hysteresis below the freezing point is incorporated through the quantification of energy required to bend and translate domain walls pinned at inclusions inherent to the material. The resulting ODE model quantities the constitutive non linearities and hysteresis exhibited by the materials through a wide range of temperatures and input drive levels. The predictive capabilities of the model are illustrated through a comparison with PMN-PT-BT data collected at temperatures ranging from 263 degrees K to 313 degrees K.