Dielectric response of ferroelectric relaxors

The real and imaginary parts of dielectric permittivities of a ferroelectric relaxor are studied by the Monte Carlo (MC) simulation as a function of frequency and temperature. The simulation results are analyzed by the fluctuation–dissipation theory (FDT). In contrast to the previous results (Appl. Phys. Lett. 69 (1996) 2353), the imaginary part of permittivity qualitatively agrees with the experimental results very well. The measuring frequency and Tpi, the temperature at which the imaginary part of dielectric permittivity reaches its maximum, follow the Vogel–Fulcher relationship. The 1/f type of noise is also found, which implies a glassy phase at low temperature. We suggest that the dipolar glass model can explain the observed non-Debye relaxation and non-Arrhenius temperature dependence of the relaxation time. The conduction loss assumption is not necessary for explaining the imaginary part of dielectric permittivity behaviors.