Grain size effects on the dielectric properties of ferroelectric Bi2VO5.5 ceramics
- 196 Downloads
Dielectric properties and microstructural characteristics of ferroelectric bismuth vanadate (Bi2VO5.5) ceramics exhibiting grain sizes of 7, 10, 20 and 25 μm have been studied. Microstructural studies indicate the presence of ferroelectric 90° domain patterns on the surface as well as in the bulk of the coarse-grained ceramics. The dielectric constant and the loss tangent both at room temperature and in the vicinity of the Curie temperature have been found to increase with increasing grain size. The Curie temperature (725 K) is found to shift slightly (by about 7 K) towards higher temperatures as the grain size increases (7–25 μm). The magnitude of the dielectric anomaly around 725 K is found to be higher for coarse-grained ceramics. The dielectric constant and the loss have been found to decrease with increase in frequency (1–100 kHz) for all the ceramics studied. The increase in dielectric constant with increasing grain size is attributed to a decrease in thickness of the relatively more insulating grain boundary layer.
KeywordsPolymer Grain Size Boundary Layer Dielectric Constant Vanadate
Unable to display preview. Download preview PDF.
- 1.V. G. Osipyan, L. M. Savchenko, V. L. Elbakyan and P. B. Avakyan, Russ. J. Inorg. Mater. 23 (1987) 467.Google Scholar
- 2.V. N. Borisov, Yu. M. Poplavko, P. B. Avakyan and V. G. Osipyan, Sow. Phys. Solid State 30 (1988) 904.Google Scholar
- 3.A. A. Bush and Yu. N. Venevtsev, Russ. J. Inorg. Chem. 31 (1986) 769.Google Scholar
- 6.K. V. R. Prasad and K. B. R. Varma, (to be published).Google Scholar
- 8.W. D. Kingery, H. K. Bowen and D. R. Uhlmann, “Introduction to Ceramics” (John Wiley, New York, 1976).Google Scholar
- 11.G. Samara, “Advances in High-pressure Research” (Academic Press, New York, 1969).Google Scholar