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Please use this identifier to cite or link to this item: http://bura.brunel.ac.uk/handle/2438/5636

Title: Electronic properties of SnO2-based ceramics with double function of varistor and humidity sensor
Authors: Glot, AB
Sandoval-García, AP
Gaponov, AV
Bulpett, R
Jones, BJ
Jimenez-Santana, G
Keywords: Electrical conduction
Grain boundary
Varistor
Electroceramics
Humidity sensor
Tin dioxide
Publication Date: 2009
Publisher: AD-TECH
Citation: Advances in Technology of Materials and Materials Processing 10: 21-32, Apr 2009
Abstract: Tin dioxide based varistor ceramics SnO2-Co3O4-Nb2O5-Cr2O3-xCuO (x=0; 0.05; 0.1 and 0.5) were made and their electrical properties were studied. The highest nonlinearity coefficient and electric field (at current density 10-3 A cm-2) were obtained for 0.1 mol.% CuO addition. It was observed that low-field electrical conductivity is increased with relative humidity, therefore, materials obtained exhibit double function of varistor and humidity sensor. The highest humidity sensitivity coefficient is found for SnO2-Co3O4-Nb2O5-Cr2O3 ceramics (without CuO). Observed varistor and humidity-sensitive properties are explained in the frames of grain-boundary double Schottky barrier concept as a decrease of the barrier height with electric field or relative humidity. Using suggested simple theory and data obtained on isothermal capacitance relaxation, the energy of the grain-boundary monoenergetic trapping states were estimated. These values are less than found for activation energy of electrical conduction (as a measure of the barrier height). These observations confirm the barrier concept.
Description: This is the post-print version of the article. The official published version can be obtained from the link below - Copyright @ 2010 AD-Tech.
Sponsorship: This work is funded by the Royal Society, United Kingdom (2007R1/R26999).
URI: http://www.azom.com/article.aspx?ArticleID=4718
http://bura.brunel.ac.uk/handle/2438/5636
DOI: http://dx.doi.org/10.2240/azojomo0277
ISSN: 1440-0731
Appears in Collections:Materials Engineering
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