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 + PbSeO3 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 (εhf) and static (εlf) permittivities of the PbSe and PbSeO3 phases are determined. The permittivities εhf = 20–45 and εlf = 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 + PbSeO3 composite undergoes a phase transition at a temperature Tc ≅ 363 K.