Study of diffuse phase transition in Pb(Cd_1/3Nb_2/3)O₃ compound

Highlights: • Pb(Cd_1/3Nb_2/3)O₃ is very new and still has not been reported. • Characterized by XRD, FESEM, temperaure dependence of dielectric study, impedance spectroscopy and hysteresis loop study. • Dielectric study exhibits diffuse phase transition due to oxygen vacancies and charge carriers. • Value of dielectric permittivity is quite high ∼4532 at frequency 5 kHz. • Electric impedance spectroscopy revealed that material has grain (bulk) resistance contribution. - Abstract: Present paper contains study of phase evolution, dielectric properties and complex impedance spectroscopy of lead based ferroelectric ceramic Pb(Cd_1/3Nb_2/3)O₃ synthesized by double step solid state reaction route. X-ray diffraction pattern shows that the material has single cubic phase. Temperature dependence of relative dielectric constant exhibits diffuse phase transition in the present compound. Frequency dependence of the real (Z′) and imaginary (Z′′) parts of the electric impedance spectroscopy reveal contribution due to grain (bulk) resistance in a wide temperature range and indicate that the relaxation mechanism is less temperature dependent and strongly influenced by oxygen vacancies and charge carrier. The conductivity spectrum has been observed to follow the Jonscher's universal power law. The existence of week ferroelectricity is confirmed from hysteresis loop study