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Microstructural, dielectric, pyroelectric and ferroelectric studies on partially grain-oriented SrBi2Ta2O9 ceramics

Murugan, Senthil G and Varma, KBR (2002) Microstructural, dielectric, pyroelectric and ferroelectric studies on partially grain-oriented SrBi2Ta2O9 ceramics. In: Journal of Electroceramics, 8 (1). pp. 37-48.

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Abstract

Partially grain-oriented (48%) ceramics of strontium bismuth tantalate (SrBi2Ta2O9) have been fabricated via conventional sintering. The grain-orientation factor of the ceramics was determined, as a function of both the sintering temperature and duration of sintering using X-ray powder diffraction (XRD) techniques. Variations in microstructural features (from acircular to plate like morphology) as a function of sintering temperature of the pellets were monitored by Scanning Electron Microscopy (SEM). The dielectric constant and loss measurements as functions of both frequency and temperature have been carried out along the directions parallel and perpendicular to the pressing axis. The anisotropy (epsilon(rn)/epsilon(rp)) associated was found to be 2.21. The effective dielectric constant of the samples with varying porosity was predicted using different dielectric mixture formulae. The grain boundary and grain interior contributions to the dielectric properties were rationalized using the impedance spectroscopy. The pyroelectric coefficient for strontium bismuth tantalate ceramic was determined along the parallel and perpendicular directions to the pressing axis and found to be -23 muC/m(2)K and -71 muC/m(2)K, respectively at 300 K. The ferroelectric properties of these partially grain-oriented ceramics are superior in the direction perpendicular to the pressing axis to that in the parallel direction.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to Springer.
Keywords: electroceramics;grain-orientation;strontium bismuth tantalate;scanning electron microscopy;dielectric;hysteresis loop
Department/Centre: Division of Chemical Sciences > Materials Research Centre
Date Deposited: 20 Jul 2011 07:19
Last Modified: 20 Jul 2011 07:19
URI: http://eprints.iisc.ernet.in/id/eprint/39282

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