Dielectric relaxation and conductivity in the PbCo0.5Ta0.5O3 ceramics

For the first time results of the dielectric properties of PbCo0.5Ta0.5O3 ceramics are reported in the frequency range of 200 Hz-1 MHz at temperatures 300-450 K. The frequency-dependent electrical data is discussed in the framework of the non-Debye relaxation using complex dielectric permittivity and electric modulus representations. The dielectric permittivity shows strong dispersion above room temperature with Arrhenius temperature dependent relaxation rate. The dielectric spectra at the low frequencies and at the high temperatures are highly influenced by the ionic conductivity. Frequency-dependent conductivity and non-Arrhenius mean electric relaxation time, obtained by the complex modulus M⁎(ω), are analyzed and similarities to ion glass state are pointed out.