Microscopic Region Effect on the Dielectric Property of the Diffused Phase Transition Ferroelectrics: A Reasonable and Effective Diffuse ness Characterizing Parameter

摘要

Based on the microscopic composition fluctuation model and phenomenological theory, a reasonable and effective characterizing parameter of the diffuseness degree of the diffused phase transition (DPT) was defined. The parameter equals to the temperature interval of T_((δε(T)δT))_(min) and T_((δε(T)δT))_(min) which correspond to the temperatures when δε(T)/δT reaches the minimum and maximum, respectively. The parameter reflects the diffuse-ness degree macroscopically and can be easily calculated. This characterizing parameter has been proved to be useful for ferroelectric materials including normal ferroelectrics, common DPT ferroelectrics, and typical relaxor ferroelectrics.