Structural and dielectric characteristics of 0.50 $Bi_2O_3$ - 0.25 $V_2O_5$ - 0.25 $SrB_4O_7$ glass-ceramic.

Shankar, MV and Varma, KBR (1996) Structural and dielectric characteristics of 0.50 $Bi_2O_3$ - 0.25 $V_2O_5$ - 0.25 $SrB_4O_7$ glass-ceramic. In: Tenth IEEE International Symposium on Applications of Ferroelectrics, 1996. ISAF '96, 18-21 August, East Brunswick,USA, Vol.2, 817 -820.

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Abstract

Novel 0.50 $Bi_2O_3$-0.25 $V_2O_5$ -0.25 $SrB_4O_7$ glasses have been prepared via a conventional splat-quenching technique. Differential thermal analysis (DTA) carried out on the as-quenched samples confirms their glassy nature and shows a prominent exothermic peak at 400°C. The X-ray powder diffraction (XRD) pattern of the heat treated sample could be indexed to an orthorhombic ferroelectric $Bi_2VO_{5.5}$ phase with the lattice parameters a=5.543, b=5.615 and c=15.321 A. The presence of nano-crystallites of bismuth vanadate, $Bi_2VO_{5.5}$ (BiV) dispersed in the glassy matrix of strontium tetraborate, $SrB_4O_7$ (SBO) is confirmed in the heat treated (at 400°C for 12 h) samples, by high resolution transmission electron microscopy (HRTEM). The dielectric constant $(\epsilon_r)$, measured as a function of temperature, exhibits an anomaly around the transition temperature of the parent crystalline BiV. The $\epsilon_r$ of the glass-ceramic at 300K is comparable with that predicted by Maxwell's model and logarithmic mixture rule.

Item Type:	Conference Paper
Publisher:	IEEE
Additional Information:	Copyright 1990 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.
Department/Centre:	Division of Chemical Sciences > Materials Research Centre
Date Deposited:	06 May 2006
Last Modified:	13 Apr 2011 06:00
URI:	http://eprints.iisc.ac.in/id/eprint/6604

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