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Influence of Ba/Ti Ratio on the Positive Temperature Coefficient of Resistivity Characteristics of Ca‐Doped Semiconducting BaTiO 3 Fired in Reducing Atmosphere and Reoxidized in Air
Author(s) -
Niimi Hideaki,
Mihara Kenjiro,
Sakabe Yukio,
Kuwabara Makoto
Publication year - 2007
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2007.01701.x
Subject(s) - reducing atmosphere , electrical resistivity and conductivity , temperature coefficient , materials science , doping , atmosphere (unit) , atmospheric temperature range , mineralogy , ceramic , analytical chemistry (journal) , composite material , optoelectronics , metallurgy , chemistry , electrical engineering , thermodynamics , physics , chromatography , engineering
The positive temperature coefficient of resistivity (PTCR) characteristics of donor‐doped BaTiO 3 fired in a reducing atmosphere and reoxidized in air are investigated. The result reveals that conventional semiconducting BaTiO 3 ceramics fired in a reducing atmosphere and reoxidized at a low temperature of 800°C in air show minimal PTCR characteristics, as reported earlier; however, Ca‐doped BaTiO 3 with compositions in the range of 1.005≤(Ba+Ca+La)/Ti≤1.010 exhibit pronounced PTCR characteristics, even when reoxidized at such a low temperature. The semiconducting BaTiO 3 ceramics with {(Ba+Ca+La)/Ti}=1.005 and Ca‐doped to 20 mol% exhibit remarkable PTCR characteristics with a resistivity jump of two orders of magnitude when they have been reoxidized at 800°C after firing in a reducing atmosphere.