Electrical conductivity and seebeck coefficient of nonstoichiometric La sub 1 minus x Sr sub x CoO sub 3 minus. delta

Journal Article · Sat Jul 01 00:00:00 EDT 1989 · Journal of the Electrochemical Society; (USA)

DOI:https://doi.org/10.1149/1.2097187· OSTI ID:6837087

Mizusaki, J ^[1]; Tabuchi, J ^[2]; Matsuura, T ^[3]; Yamauchi, S ^[4]; Fucki, K ^[5]

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1. Inst. of Environmental Science and Technology, Yokohama National Univ., Tokiwadai, Hodogaya-ku, Yokohama 240 (JP)
2. Fundamental Research Laboratories, NEC Corporation, Miyamae-ku, Kawasaki 213 (JP)
3. Research Inst. of Electrical Communication, Tohoku Univ., Katahira, Sendai 980 (JP)
4. Research Inst., National Rehabilitation Center of Disabled, Namiki, Tokorozawa, Saitama 359 (JP)
5. Dept. of Industrial Chemistry, Science Univ. of Tokyo, Yamazaki, Noda, Chiba 278 (JP)

This paper reports the conductivity and Seebeck coefficient of the perovskite-type oxides La{sub 1 {minus} x}Sr{sub x}CoO{sub 3 {minus} {delta}}(x = 0-0.7) measured in 10{sup {minus} 5}-1 atm O{sub 2} gas at temperatures 25{degrees}-1000{degrees}C. The results are discussed in relation to the lattice-parameter and oxygen nonstoichiometry. Close relationships were found between the temperature dependence of the conductivity and the rhombohedral angle, {alpha}. For La{sub 1 {minus} x}Sr{sub x}CoO{sub 3 {minus} {delta}} {lt} 60.3{degrees}-60.4{degrees} (LaCoO{sub 3 {minus} {delta}} above 800{degrees}C and La{sub 1 {minus} x}Sr{sub x}CoO{sub 3 {minus} {delta}} with x {gt} 0.5 at room temperature), the conductivity decreases with temperature, suggesting metallic conduction. For La{sub 1 {minus} x}Sr{sub x}CoO{sub 3 {minus} {delta}} with {alpha} {gt} 60.4{degrees}, the conductivity increases with temperature like semiconductors. In the oxides with metallic conduction, the conductivity was found to decrease with increase in the oxygen vacancy concentration. Because the conduction band is composed of the Co-O-Co network, it is considered that the band is distributed by the formation of oxygen vacancies and becomes narrower, resulting in the decrease in conductivity.

• OSTI ID: 6837087
• Journal Information: Journal of the Electrochemical Society; (USA), Journal Name: Journal of the Electrochemical Society; (USA) Journal Issue: 7 Vol. 136:7; ISSN 0013-4651; ISSN JESOA
• Country of Publication: United States
• Language: English

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ALKALINE EARTH METAL COMPOUNDS
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