Microstructural, dielectric, impedance and electric modulus studies on vanadium—doped and pure strontium bismuth niobate $(SrBi_2Nb_2O_9)$ ceramics

Venkataraman, BH and Varma, KBR (2005) Microstructural, dielectric, impedance and electric modulus studies on vanadium—doped and pure strontium bismuth niobate $(SrBi_2Nb_2O_9)$ ceramics. In: Journal of Materials Science: Materials in Electronics, 16 (6). pp. 335-344.

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Abstract

$SrBi_2Nb_2O_9$ (SBN) and $SrBi_2(Nb_{0.9}V_{0.1})_2O_9$ (SBVN) ceramics were fabricated from the powders consisting of $\mu m$ sized grains, obtained via the solid state reaction route. $V_2O_5$ was found to be an effective microstructure modifier and grain growth truncator for SBN ceramics. X-ray structural studies carried out on SBVN ceramics confirmed the existence of preferential orientation (c-planes) of the grains. $V_2O_5$ addition has substantially improved the sinterability of SBN and enabled to achieve high density (95%) which was otherwise difficult in the case of pure SBN. The dielectric properties of SBN ceramics were significantly enhanced by the partial replacement of Nb ions by pentavalent vanadium ions. The complex impedance diagrams of dense SBVN ceramics exhibited only one semicircle indicating a significant contribution from the grains. In contrast, the impedance plots for the porous (density 88%) SBN ceramics show an additional low-frequency semicircle which was attributed to the blocker (pore) size effects. The dielectric behavior of SBN and SBVN ceramics was rationalized using the impedance and modulus data.

Item Type: Journal Article Copyright of this article belongs to Springer. Division of Chemical Sciences > Materials Research Centre 22 Aug 2008 19 Sep 2010 04:35 http://eprints.iisc.ernet.in/id/eprint/9746