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

Yuzuru Miyazaki, Tatsuro Miura, Yasuhiro Ono, Tsuyoshi Kajitani

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)

Abstract

Polycrystalline samples of [(Ca1-xSrx)2CoO3]p CoO2 with 0 ≤×≤ 0.20 have been synthesized at 1193 K 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 = 150 μΩm 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 110 μW/m/K2 (x=0) to 140 μW/m/K2 (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
Pages (from-to)475-479
Number of pages5
JournalFuntai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy
Volume50
Issue number6
DOIs
Publication statusPublished - 2003 Jun

Keywords

  • Calcium strontium cobalt oxide
  • Composite crystal
  • Crystal structure
  • Thermoelectric compound
  • Thermoelectric power factor

ASJC Scopus subject areas

  • Mechanical Engineering
  • Industrial and Manufacturing Engineering
  • Metals and Alloys
  • Materials Chemistry

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