Dielectric Properties and Phase Transition in the PbSe + PbSeO3 Composite Material

Electrochemical cells in the form of pressed pellets and polycrystalline films prepared from the PbSe + PbSeO^sub 3^ two-phase composite are investigated by impedance spectroscopy. The dispersion analysis of the frequencies of the real and imaginary parts of the complex impedance made it possible to reveal a unified equivalent electric circuit for these cells and to calculate its parameters. The optical (ε^sub hf^) and static (ε^sub lf^) permittivities of the PbSe and PbSeO^sub 3^ phases are determined. The permittivities ε^sub hf^ = 20-45 and ε^sub lf^ = 200-280 obtained for the PbSe phase are in reasonable agreement with the data available in the literature. The temperature dependences of the ac and dc resistances indicate that the PbSe + PbSeO^sub 3^ composite undergoes a phase transition at a temperature T^sub c^ 363 K.[PUBLICATION ABSTRACT]