Dielectric and Mössbauer Studies of High-Permittivity BaFe_1/2Nb_1/2O₃Ceramics with Cubic and Monoclinic Perovskite Structures

Abstract

Ceramic samples of monoclinic and cubic modifications of ternary perovskite BaFe 1/2 Nb 1/2 O 3 have been obtained by solid-state reaction route. Mossbauer 57 Fe spectra and Neel temperature values appeared to be very similar for both modifications. The values and temperature dependences of the dielectric permittivity for BaFe 1/2 Nb 1/2 O 3 samples were found to depend primarily on their apparent resistivity values and not on their structure. Thus high permittivity values of BaFe 1/2 Nb 1/2 O 3 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.