Investigating the physical meanings of diffused phase transition models

Abstract The empirical laws, ɛ  =  ɛ m /[1 + ( T  −  T m ) γ /2 σ 2 ] and ɛ  =  ɛ m /{1 + [( T  −  T m )/ Δ ] ξ }, proposed by Burfoot et al. and Eiras et al. are usually used to describe the dielectric diffused characteristics of relaxor ferroelectric materials. In this study, we continue our previous work to present the physical and mathematical meanings of the parameters in these laws. Based on the experimental results in the (1 −  x )Pb(Fe 2/3 W 1/3 )O 3 – x PbTiO 3 relaxor system and theoretical modelling analysis, it is shown that the law proposed by Eiras is more suitable to explain the behaviour of both more complete relaxor systems and incomplete relaxor systems.