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Structural and electrical properties of bismuth magnesium tantalate pyrochlores.


Tan, P. Y. and Tan, Kar Ban and Khaw, Chwin Chieh and Zainal, Zulkarnain and Chen, Soo Kien and Chon, Mun Ping (2012) Structural and electrical properties of bismuth magnesium tantalate pyrochlores. Ceramics International, 38 (7). pp. 5401-5409. ISSN 0272-8842


The subsolidus cubic pyrochlore phases in the Bi2O3–MgO–Ta2O5 (BMT) system were prepared with the proposed formula, Bi3+(5/2)xMg2−xTa3−(3/2)xO14−x (0.12 ≤ x ≤ 0.22). Replacement of smaller cations, Mg2+ and Ta5+ by larger Bi3+ cations with considerable oxygen non-stoichiometry within structure was proposed. The synthesised samples were confirmed phase pure by X-ray powder diffraction and their refined lattice parameters were in the range of 10.5532(4)–10.5672(9) Å. The grain sizes of the samples determined by SEM analysis were in the range of 0.6–10.60 μm and their average relative densities were more than 80%. Five infrared-active modes were also observed in their FTIR spectra due to their metalsingle bondoxygen bonds. The BMT pyrochlores were highly electrical resistive with high dielectric constants, ɛ′ in the range of ∼70–85; dielectric losses, tan δ in the order of 10−3 at frequency 1 MHz and a negative temperature coefficient of permittivities, TCɛ′ of ∼−158 to −328 ppm/°C.

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Additional Metadata

Item Type: Article
Divisions: Faculty of Science
DOI Number: https://doi.org/10.1016/j.ceramint.2012.03.050
Publisher: Elsevier Limited
Keywords: C. Dielectric properties; D. Tantalates; Pyrochlores; Ceramics.
Depositing User: Nur Farahin Ramli
Date Deposited: 24 Oct 2013 00:07
Last Modified: 12 Jan 2016 01:29
Altmetrics: http://www.altmetric.com/details.php?domain=psasir.upm.edu.my&doi=10.1016/j.ceramint.2012.03.050
URI: http://psasir.upm.edu.my/id/eprint/25309
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