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 language | English |
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Pages (from-to) | 475-479 |
Number of pages | 5 |
Journal | Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy |
Volume | 50 |
Issue number | 6 |
DOIs | |
Publication status | Published - 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