Work

Scanning Transmission Electron Microscopy and Thermoelectric Properties of Sr-Doped Misfit Cobalt Oxide

Year: 2013

Type: article

Abstract: In order to clarify the role of Sr doping in the themoelectric properties of Ca3Co4O9, Ca3-x Sr x Co4O9 samples were fabricated by uniaxial compression molding and sintering in atmosphere. Their thermoelectric properties and atomic-scale structures were investigated. For x<0.3, the dimensionless figure of merit (Z T) increases with x through a decrease in the thermal conductivity κ despite the nearly constant Seebeck coefficient α and electrical resistivity ρ. 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 Z T by decreasing κ in the rocksalt layer, but it does not significantly affect electrical properties because it is an isovalent substitution.

Source: Japanese Journal of Applied Physics

DOI: 10.7567/jjap.52.071101

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

Institutions: Nagasaki University, The University of Tokyo, Tohoku University, Japan Fine Ceramics Center, Advanced Institute for Materials Research, Tohoku University

Language: English

Topic: Advanced Thermoelectric Materials and Devices

Subfield: Materials Chemistry

Field: Materials Science

Domain: Physical Sciences

Open Access status: bronze

Funders: Ministry of Education, Culture, Sports, Science and Technology, University of Tokyo, Japan Society for the Promotion of Science

Awards: G364767506, G4298611931, G4300310345, In-situ and atomic-scale observation of nano-scale ferroelectric domain structure, G8116476298