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High‐Temperature Electrical Conductivity of LaCr 1− x Co x O 3 Ceramics
Author(s) -
Bonet Alexander,
Baben Moritz,
Travitzky Nahum,
Greil Peter
Publication year - 2016
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/jace.14038
Subject(s) - electrical resistivity and conductivity , ceramic , materials science , sintering , conductivity , analytical chemistry (journal) , polaron , x ray photoelectron spectroscopy , atmospheric temperature range , doping , inorganic chemistry , mineralogy , chemistry , chemical engineering , metallurgy , thermodynamics , physics , optoelectronics , chromatography , quantum mechanics , electrical engineering , engineering , electron
LaCr 1− x Co x O 3 solid‐solution ceramics ( x = 0.0–0.3) were prepared by pressureless sintering of a submicrometer powder. The powder was synthesized by a modified glycine nitrate process at 800°C. The electrical conductivity of the material sintered at 1600°C was measured by AC four‐wire method from room temperature to 1200°C. While undoped ( x = 0) LaCrO 3 revealed semiconductivity dominated by thermally activated mobility of small polarons over a vast temperature range, substitution of Co for Cr gave rise for a pronounced enhancement of conductivity at temperatures >200°C. XPS analysis showed that the concentration of Cr 4+ on the Cr‐site and Co 2+ at the Co‐site increased with Co substitution suggesting a thermally activated redox reaction Cr 3+ + Co 3+ →Cr 4+ + Co 2+ to create additional charge carriers. Thus, Co doping offers a high potential for designing the electrical conductivity making LaCr 1− x Co x O 3 an interesting resistivity material for high temperature applications.