Dielectric and Mossbauer Studies of High-Permittivity BaFe1/2Nb1/2O3 Ceramics with Cubic and Monoclinic Perovskite Structures

Ceramic samples of monoclinic and cubic modifications of ternary perovskite BaFe1/2Nb1/2O3 have been obtained by solid-state reaction route. Mossbauer Fe-57 spectra and Neel temperature values appeared to be very similar for both modifications. The values and temperature dependences of the dielectric permittivity for BaFe1/2Nb1/2O3 samples were found to depend primarily on their apparent resistivity values and not on their structure. Thus high permittivity values of BaFe1/2Nb1/2O3 are due not to the ferroelectric relaxor behavior but rather to the relaxation of the Maxwell-Wagner type and/or relaxation contributed by the oxygen vacancies.