Dielectric relaxation of free charge carriers in some fluorite-type solid solutions

Low-frequency dielectric relaxation was observed in solid solutions Ba1 − xThxF2 + x and Cd1 − xErxF2 + x of fluorite type. The relaxation can be satisfactorily described by the Havriliak-Negami formula: e∗(f) − e∞ = Δe/ {1 + [if/fr]1 − β}1 − γ. The activation energy for relaxation turned to be equal to that for DC-conductivity in the system under study. This suggests that the relaxation is closely related to the ion transport and agrees with the model of a dipole-like behavior of free charge carriers. The relaxation is of strongly non-Debye type and contributes to the high frequency conductivity in the form: σ = σDC[1 + (f/fh)α] with α = β + γ − βγ.