Scanning transmission electron microscopy and thermoelectric properties of Sr-doped misfit cobalt oxide

Takao Morimura; Yukio Sato; Yuichi Ikuhara; Takahiro Yamaguchi; Masayuki Hasaka

doi:10.7567/JJAP.52.071101

Scanning transmission electron microscopy and thermoelectric properties of Sr-doped misfit cobalt oxide

Takao Morimura, Yukio Sato, Yuichi Ikuhara, Takahiro Yamaguchi, Masayuki Hasaka

Research output: Contribution to journal › Article

1 Citation (Scopus)

Abstract

In order to clarify the role of Sr doping in the themoelectric properties of Ca₃Co₄O₉, Ca_3-x SrxCo ₄O₉ samples were fabricated by uniaxial compression molding and sintering in atmosphere. Their thermoelectric properties and atomic-scale structures were investigated. Forx < 0:3, the dimensionless figure of merit (ZT) increases with x through a decrease in the thermal conductivity despite the nearly constant Seebeck coefficient and electrical resistivity. Scanning transmission electron microscopy images and energy-dispersive X-ray spectroscopy maps have revealed that Sr mainly substitutes in the Ca site in the rocksalt layer. These results suggest that Sr doping enhances ZT by decreasing in the rocksalt layer, but it does not significantly affect electrical properties because it is an isovalent substitution.

Original language	English
Article number	071101
Journal	Japanese journal of applied physics
Volume	52
Issue number	7 PART 1
DOIs	https://doi.org/10.7567/JJAP.52.071101
Publication status	Published - 2013 Jan 1

ASJC Scopus subject areas

Engineering(all)
Physics and Astronomy(all)

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Morimura, T., Sato, Y., Ikuhara, Y., Yamaguchi, T., & Hasaka, M. (2013). Scanning transmission electron microscopy and thermoelectric properties of Sr-doped misfit cobalt oxide. Japanese journal of applied physics, 52(7 PART 1), [071101]. https://doi.org/10.7567/JJAP.52.071101

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abstract = "In order to clarify the role of Sr doping in the themoelectric properties of Ca3Co4O9, Ca3-x SrxCo 4O9 samples were fabricated by uniaxial compression molding and sintering in atmosphere. Their thermoelectric properties and atomic-scale structures were investigated. Forx < 0:3, the dimensionless figure of merit (ZT) increases with x through a decrease in the thermal conductivity despite the nearly constant Seebeck coefficient and electrical resistivity. Scanning transmission electron microscopy images and energy-dispersive X-ray spectroscopy maps have revealed that Sr mainly substitutes in the Ca site in the rocksalt layer. These results suggest that Sr doping enhances ZT by decreasing in the rocksalt layer, but it does not significantly affect electrical properties because it is an isovalent substitution.",

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