Crystal structure and thermoelectric properties of the composite crystal [(Ca1-xSrx)2CoO3]pCoO2

Y. Miyazaki, T. Miura, Y. Ono, T. Akashi, T. Goto, T. Kajitani

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

9 Citations (Scopus)


Polycrystalline samples of [(Ca1-xSrx)2CoO3]pCoO2 with 0 ≤5 x≤0.25 have been synthesized at 920°C in flowing oxygen gas. The modulated crystal structure of the samples has been determined in accordance with a four-dimensional formalism from powder neutron diffraction data. With increasing x, the modulation amplitudes in Co-Co conduction paths become less marked. The non-doped sample (x=0) exhibits the resistivity ρ =15 mΩcm and the thermoelectric power S=130 μV/K at 300 K. Both the ρ and S values decrease with x but the decrease in ρ values is steeper than that of the S values. The power factor S2/ρ increases with x, from 1.1×10-4 W/mK2 (x=0) to 1.4×10-4 W/mK2 (x=0.20) at 300 K. This improvement in thermoelectric performance can be explained in terms of the reduction of displacive modulation of the Co-Co conduction paths in the CoO2 sheets.

Original languageEnglish
Title of host publicationProceedings ICT 2002
Subtitle of host publication21st International Conference on Thermoelectrics
PublisherInstitute of Electrical and Electronics Engineers Inc.
Number of pages4
ISBN (Electronic)0780376838
Publication statusPublished - 2002
Event21st International Conference on Thermoelectrics, ICT 2002 - Long Beach, United States
Duration: 2002 Aug 252002 Aug 29

Publication series

NameInternational Conference on Thermoelectrics, ICT, Proceedings


Conference21st International Conference on Thermoelectrics, ICT 2002
Country/TerritoryUnited States
CityLong Beach


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