Numerical study on dielectric permittivity for the ferroelectric ceramic with composition KTa0.6Nb0.4O3

Based on the Debye theory, we have determined the evolution of the dielectric permittivity of the ceramic with composition KTa0.6Nb0.4O3 as a function of temperature and frequency. This evolution shows that this composition exhibits a ferroelectric–paraelectric phase transition at 360 K with dispersion at high frequencies (106–6 × 108 Hz). A comparison between experimental and numeric calculation of dielectric permittivity for this solid solution has been suggested using a Gaussian distribution of the relaxation times, which was introduced in Debye relations. The numerical results were in agreement with experimental data.

Research highlights▶ We have determined, based on the Debye theory, the evolution of the dielectric permittivity of the ceramic with composition KTa0.6Nb0.4O3 as a function of temperature and frequency. ▶ This evolution shows that this composition exhibits a ferroelectric-paraelectric phase transition at 360 K with dispersion at high frequencies (106–6 × 106 Hz). ▶ A comparison between experimental and numeric study of dielectric permittivity for this solid solution has been suggested using a Gaussian distribution of the relaxation times.