Dielectric properties of Sr<inf>1-x</inf>Ba<inf>x</inf>Fe<inf>0.5</inf>Nb<inf>0.5</inf>O<inf>3</inf>; (x = 0.0, 0.1 and 0.2) ceramics prepared by the molten salt technique and their electrode effects

Abstract

© 2016 Elsevier B.V. In the present work, strontium barium iron niobate (Sr1-xBaxFe0.5Nb0.5O3; SBFN) (x = 0.0, 0.1 and 0.2) powders were synthesized via the molten salt technique. Pure phase perovskite powders were obtained at a relatively low calcination temperature of 800 °C which was 400 °C lower than for the solid-state reaction technique (conventional technique). SBFN ceramics were fabricated from the calcined powders and their properties were investigated. XRD data of the ceramics was consistent with an orthorhombic symmetry. All ceramics showed very high dielectric constants where the x = 0.1 ceramic showed an extremely high dielectric constant (εr ~ 1.98 × 105at 298 °C and 1 kHz, for an Ag electrode) when compared to SFN ceramics prepared by the conventional solid-state reaction technique. The dielectric behavior of the ceramics could be explained in terms of the Maxwell-Wagner mechanism as the ceramics exhibited heterogeneous conduction where an electrode response gave a strong effect in the low frequency and high temperature regions. In addition, the type of electrode (sample-electrode interface) also affected the dielectric constants of the ceramics.