Dielectric response of doped [Bi.sub.12]Ti[O.sub.20] : Ru crystals in an alternating electric field

The results of examination of AC dependences of capacitance and dielectric loss tangent of sillenite [Bi.sub.12]Ti[O.sub.20] crystals doped with ruthenium on frequency are presented. Non-Debye dispersion of dielectric coefficients is found in the frequency interval of 5 x [10.sup.2] - [10.sup.5] Hz, and a resonance phenomenon is observed. Polarization processes in the studied samples are attributed to relaxators associated with metal-oxygen vacancies and structural elements incorporating [6s.sup.2] lone-pair electrons.