NUMERICAL ANALYSIS OF DIELECTRIC RESPONSE IN RELAXOR FERROELECTRICS

The dielectric response of complex perovskite relaxor ferrolectrics Pb(Mg1/3Nb2/3) O3 with respect to temperature and frequency was carefully measured. Using a normalized method of the 'universal' many-body theory, the relaxation process was analyzed around the temperature of dielectric absorption maximum. There is no structural phase transition near this temperature and the behavior is closely like that of a polar dipole medium. The functional relationship about frequency and temperature of dielectric pormittivity maximum was also fitted to discuss the dynamic behavior of polar microregion. It is confirmed that a new power exponential Arrhenius relation is better to characterize the relaxation behavior than the Vogel-Fulcher and Debye relations. Based on the polarization theory of polar dipoles, we analyzed the relaxation mechanism of ferroelectric microdomains of relaxor ferroelectrics, and get an ideal distribution function of relaxation time. Consequently, a simulated dielectric response dependence on temperature and frequencies can be expressed, which is well coincided with experiment results.