Study of kinetics of segnetoelectric diffuse phase transition in barium-strontiun niobates

Temperature dependences of dielectric permeability has been studied in a wide temperature range up to 109 Hz and kinetics of ferroelectrics with a diffused phase transition in barium-strontium niobates have been investigated. The crystals of Basub(x)Srsub(1-x)Nbsub(2)Osub(6) have been studied in a range of x from 0.27 to 0.54. The procedure and algorythm have been proposed for solution of an electrodynamic problem of determining complex dielectric permeability epsilon = epsilon ' (1-i tg delta) at tg delta >= 1 on the basis of the exact solution for the main type of the wave coaxial with a cylindrical sample. The measurements have been performed in a wide temperature range. The data obtained are useful for evaluating the modulation characteristics of these materials as optical gates