Electronic Conduction Mechanisms in BaTiO3-Ni Composites with Ultrafine Microstructure Obtained by Spark Plasma Sintering
2010 (English)In: Journal of The American Ceramic Society, ISSN 0002-7820, E-ISSN 1551-2916, Vol. 93, no 12, 4075-4080 p.Article in journal (Refereed) Published
Spark plasma sintering (SPS) was used to densify BaTiO3-Ni composite powders to relative densities above 92.8%. With the increasing Ni content, a decrease in relative density is observed, suggesting that Ni hampers the consolidation process. The microstructures of the BaTiO3-Ni composites were of duplex character. The crystallite size of the BaTiO3-grains was around 100 nm in average. The ceramic matrix phase of BaTiO3 surrounded Ni inclusions of approximately 1 mu m in diameter that were completely incorporated without the formation of any elongated metallic filaments. The ac conductivity of these BaTiO3-Ni composites increased with increasing Ni content and with temperature. The dominant conduction mechanisms in SPSed BaTiO3-Ni composites showed quite a complicated behavior. A gradual change from band conduction of trapped electrons in oxygen vacancies to a hopping-type motion of small polarons between Ti4+ and Ti3+ is suggested to occur, when the Ni content increases. The influence of oxygen vacancies and other lattice defects on the electrical properties of BaTiO3-Ni composites is discussed.
Place, publisher, year, edition, pages
2010. Vol. 93, no 12, 4075-4080 p.
ELECTRICAL-TRANSPORT PROPERTIES; N-TYPE BATIO3; DIELECTRIC-CONSTANT; BARIUM-TITANATE; THIN-FILMS; CERAMICS; BEHAVIOR; ALUMINA; SIMULATION
Research subject Materials Chemistry
IdentifiersURN: urn:nbn:se:su:diva-51258DOI: 10.1111/j.1551-2916.2010.04011.xISI: 000284849300027OAI: oai:DiVA.org:su-51258DiVA: diva2:385119
authorCount :82011-01-112011-01-102011-01-11Bibliographically approved