Structural and dielectric properties of relaxor Sr_0.5Ba_0.5Bi₂Nb₂O₉ ceramic

Authors: B. Behera, E. B. Araújo, A. F. Júnior

Source: Advances in Applied Ceramics

Publisher: Maney Publishing

Abstract:

Sr_0.5Ba_0.5Bi₂Nb₂O₉ ceramic was prepared by a conventional solid state reaction method and studied using X-ray powder diffraction and dielectric measurements. At room temperature, an orthorhombic structure was confirmed and their parameters were obtained using the Rietveld method. Dielectric properties were studied in a broad range of temperatures and frequencies. Typical relaxor behaviour was observed with strong dispersion of the complex relative dielectric permittivity. The temperature of the maximum dielectric constant T_m decreases with increasing frequency, and shifts towards higher temperature side. The activation energy E_a≈0.194±0.003 eV and freezing temperature T_f≈371±2 K values were found using the Vögel-Fulcher relationship. Conduction process in the material may be due to the hopping of charge carriers at low temperatures and small polarons and/or singly ionised oxygen vacancies at higher temperatures.

Document Type:

DOI: 10.1179/174367509X12447975734195

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