TY - JOUR
T1 - Synthesis, crystal structures and high-temperature thermoelectric properties of spinel-type cobalt ruthenium oxides
AU - Kawano, Tetsuya
AU - Takahashi, Junichi
AU - Okutani, Takeshi
AU - Yamada, Takahiro
AU - Yamane, Hisanori
N1 - Funding Information:
This work was partly supported by Grant of Izumi Science and Technology Foundation, and performed under the interuniversity cooperative research program of the Institute for Materials Research, Tohoku University. The authors would like to thank Dr. Kunio Takada and Mr. Kazuo Sakata for their cooperation in the analyses of compositions. Useful discussion on the thermal conductivity with Prof. Michitaka Ohtaki was appreciated.
PY - 2009/1/22
Y1 - 2009/1/22
N2 - Solid solutions of spinel-type cobalt-ruthenium oxides Co3-xRuxOy (0.50 ≤ x ≤ 0.70, y = 3.8-3.9) were prepared from Co3O4 and RuO2 powders by solid-state reaction at 1173-1273 K in air. The crystal structures of the solid solutions were refined by Rietveld analysis of powder X-ray diffraction (XRD) patterns. The solid solutions crystallized in cubic cells (space group: F d over(3, ̄) m) with formal compositions of (Co)tet[Co2-xRux]octOy, where tet refers to the tetrahedral site and oct the octahedral one. The electrical transport property of the solid solutions exhibited semiconducting behavior and positive Seebeck coefficient in the temperature range from 298 to 1073 K. The thermal conductivity increased with increasing temperature. The maximum dimensionless figure of merit of 0.024 was measured for Co2.35Ru0.65O3.86 at 973 K.
AB - Solid solutions of spinel-type cobalt-ruthenium oxides Co3-xRuxOy (0.50 ≤ x ≤ 0.70, y = 3.8-3.9) were prepared from Co3O4 and RuO2 powders by solid-state reaction at 1173-1273 K in air. The crystal structures of the solid solutions were refined by Rietveld analysis of powder X-ray diffraction (XRD) patterns. The solid solutions crystallized in cubic cells (space group: F d over(3, ̄) m) with formal compositions of (Co)tet[Co2-xRux]octOy, where tet refers to the tetrahedral site and oct the octahedral one. The electrical transport property of the solid solutions exhibited semiconducting behavior and positive Seebeck coefficient in the temperature range from 298 to 1073 K. The thermal conductivity increased with increasing temperature. The maximum dimensionless figure of merit of 0.024 was measured for Co2.35Ru0.65O3.86 at 973 K.
KW - Powder X-ray diffraction
KW - Rietveld analysis
KW - Solid-state reaction
KW - Spinel-type structure
KW - Thermoelectric materials
KW - Transition-metal oxides
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U2 - 10.1016/j.jallcom.2008.01.024
DO - 10.1016/j.jallcom.2008.01.024
M3 - Article
AN - SCOPUS:58049206592
SN - 0925-8388
VL - 468
SP - 447
EP - 451
JO - Journal of Alloys and Compounds
JF - Journal of Alloys and Compounds
IS - 1-2
ER -