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Relation between Seebeck Coefficient and Lattice Parameters of (Ca2−y Sr y CoO3) x CoO2

Kwon, O-Jong and Jo, Wook and Yoon, Sejin and Shin, Dongmin and You, Hyunwoo and Choi, Kyeongdal and Kim, Jin-Sang and Park, Chan (2012):
Relation between Seebeck Coefficient and Lattice Parameters of (Ca2−y Sr y CoO3) x CoO2.
In: Journal of Electronic Materials, pp. 1513-1518, 41, (6), ISSN 0361-5235, [Online-Edition: http://dx.doi.org/10.1007/s11664-012-1983-z],
[Article]

Abstract

The effect of dopant content on the Seebeck coefficient of the Sr2+-doped (Ca2−y Sr y CoO3) x CoO2 (y = 0 to 0.4) system was investigated. This system can be described as a misfit layered structure of (CoO2) and (Ca2−y Sr y CoO3) layers, which have different b lattice parameters denoted by b 1 and b 2, respectively. Due to the solubility limit of Sr in (Ca2CoO3) x CoO2, systematic investigations were available only up to y = 0.2. Nevertheless, the structural uniqueness enabled partially quantitative analysis of the correlation between the crystal structure and Seebeck coefficient of the system. Substitution of Sr for Ca leads to lattice expansion which accompanies an anisotropic change of the lattice parameters. Among the lattice parameters considered, the increase in the lattice parameter b 2 of the insulating layer was larger than the change of any other lattice parameter, which induced in-plane stress in the conducting layer. As a result, as the b 1/b 2 misfit ratio of (Ca2−y Sr y CoO3) x CoO2 is decreased, the Seebeck coefficient also decreases. Practical guidance for selecting dopants to enhance thermoelectric performance is proposed.

Item Type: Article
Erschienen: 2012
Creators: Kwon, O-Jong and Jo, Wook and Yoon, Sejin and Shin, Dongmin and You, Hyunwoo and Choi, Kyeongdal and Kim, Jin-Sang and Park, Chan
Title: Relation between Seebeck Coefficient and Lattice Parameters of (Ca2−y Sr y CoO3) x CoO2
Language: English
Abstract:

The effect of dopant content on the Seebeck coefficient of the Sr2+-doped (Ca2−y Sr y CoO3) x CoO2 (y = 0 to 0.4) system was investigated. This system can be described as a misfit layered structure of (CoO2) and (Ca2−y Sr y CoO3) layers, which have different b lattice parameters denoted by b 1 and b 2, respectively. Due to the solubility limit of Sr in (Ca2CoO3) x CoO2, systematic investigations were available only up to y = 0.2. Nevertheless, the structural uniqueness enabled partially quantitative analysis of the correlation between the crystal structure and Seebeck coefficient of the system. Substitution of Sr for Ca leads to lattice expansion which accompanies an anisotropic change of the lattice parameters. Among the lattice parameters considered, the increase in the lattice parameter b 2 of the insulating layer was larger than the change of any other lattice parameter, which induced in-plane stress in the conducting layer. As a result, as the b 1/b 2 misfit ratio of (Ca2−y Sr y CoO3) x CoO2 is decreased, the Seebeck coefficient also decreases. Practical guidance for selecting dopants to enhance thermoelectric performance is proposed.

Journal or Publication Title: Journal of Electronic Materials
Volume: 41
Number: 6
Uncontrolled Keywords: Thermoelectricity – oxide thermoelectric materials – layered structure – Ca3Co4O9 – Rietveld refinement
Divisions: 11 Department of Materials and Earth Sciences > Material Science > Nonmetallic-Inorganic Materials
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences
Date Deposited: 30 May 2012 07:23
Official URL: http://dx.doi.org/10.1007/s11664-012-1983-z
Identification Number: doi:10.1007/s11664-012-1983-z
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