High Dielectric Permittivity in AFe$_{1 / 2}$B$_{1 / 2}$O$_{3}$   Nonferroelectric Perovskite Ceramics (A - Ba, Sr, Ca; B - Nb, Ta, Sb)
  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. 
I.P. Raevski, S.A. Prosandeev, A.S. Bogatin, M.A. Malitskaya