The dielectric behaviors of (1−x)Pb(Mg 1/3 Nb 2/3 )O 3 −xPb(Zr 0.53 Ti 0.47 )O 3 (PMN-PZT) relaxor ferroelectric ceramics of several compositions (x = 0.05-0.30) have been studied under high bias electric field. The dielectric constant decay with dc electric field was observed in the range of diffuse phase transitions. The nonlinear dielectric response was considered in frames of thermodynamic approach. It was shown also that all dielectric features may be understood using a model involving heterogeneous polar micro-and nanoregions.

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The temperature dependence of the local order parameter and relaxation time distribution function have been determined in (1 – x)PMN–xPZT ceramic samples via dielectric permittivity. Above the Burns temperature, the permittivity was found to follow the Currie–Weiss law, and with temperature decreasing the deviation was observed to increase. A local order parameter was calculated from the dielectric data using a modified Landau–Devonshire approach. These results are compared to the distribution function of relaxation times. It was found that a glasslike freezing of reorientable polar clusters occurs in the temperature range of diffuse relaxor transition. The evolution of the studied system to more ordered state arises from the increased PZT content. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

O 3 solid solutions has been studied in the frequency range 40 ÷ 10 6 Hz. Cole-Cole plots analysis of experimental data showed that the dielectric spectrum diffuseness degree α is high in a very wide temperature range in the case of relaxor compound but α is fast decreased below phase transition in the case of ferroelecrtic compound. The computer simulation of relaxor compound dielectric spectrum revealed that the average relaxation time to be almost temperature independent below some temperature. The temperatures of ε and ε maxima follow the Vogel-Fulcher equation but the distribution of relaxation times remains finite in the whole temperature range and the distribution function is very large, nearly uniform and temperature independent below the VogelFulcher temperature in the case of relaxor compound.

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