  AFe$_{1 / 2}$B$_{1 / 2}$O$_{3}$(A- Ba, Sr, Ca; B-Nb, Ta, Sb) ceramics were
synthesized and temperature dependencies of the dielectric permittivity were
measured at different frequencies. The experimental data obtained show very
high values of the dielectric permittivity in a wide temperature interval that
is inherent to so-called high-k materials. The analyses of these data establish
a Maxwell-Wagner mechanism as a main source for the phenomenon observed.
