Abstract
Although successful examples of thermoelectric materials with the "rattler-in-a-cage" structure include filled skutterudites and clathrate compounds, there has been no report on "rattling" oxides. Here we report the thermal properties of defect pyrochlore (β-pyrochlore) oxides with smaller cations in an oversized cage-like crystal structure. It is clearly shown that the thermal diffusivity, α and the thermal conductivity, κ, are lower for the oxides containing lighter A-site cations, contradicting the conventional prediction of the phonon thermal conductivity, in which lighter comprising atoms must give higher α and hence κ. These results strongly suggest that the smaller A-site cations with larger size mismatch to the surrounding cage structure enhance the phonon scattering and thereby reduce α and κ. These findings directly evidence the "rattling" effect of the loosely bound cations on the thermal transport properties of oxide materials.
| Original language | English |
|---|---|
| Pages (from-to) | 1299-1302 |
| Number of pages | 4 |
| Journal | Journal of Electronic Materials |
| Volume | 42 |
| Issue number | 7 |
| DOIs | |
| Publication status | Published - Jul 1 2013 |
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All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering
- Materials Chemistry
Cite this
Extremely low thermal conductivity in oxides with cage-like crystal structure. / Ohtaki, Michitaka; Miyaishi, So.
In: Journal of Electronic Materials, Vol. 42, No. 7, 01.07.2013, p. 1299-1302.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Extremely low thermal conductivity in oxides with cage-like crystal structure
AU - Ohtaki, Michitaka
AU - Miyaishi, So
PY - 2013/7/1
Y1 - 2013/7/1
N2 - Although successful examples of thermoelectric materials with the "rattler-in-a-cage" structure include filled skutterudites and clathrate compounds, there has been no report on "rattling" oxides. Here we report the thermal properties of defect pyrochlore (β-pyrochlore) oxides with smaller cations in an oversized cage-like crystal structure. It is clearly shown that the thermal diffusivity, α and the thermal conductivity, κ, are lower for the oxides containing lighter A-site cations, contradicting the conventional prediction of the phonon thermal conductivity, in which lighter comprising atoms must give higher α and hence κ. These results strongly suggest that the smaller A-site cations with larger size mismatch to the surrounding cage structure enhance the phonon scattering and thereby reduce α and κ. These findings directly evidence the "rattling" effect of the loosely bound cations on the thermal transport properties of oxide materials.
AB - Although successful examples of thermoelectric materials with the "rattler-in-a-cage" structure include filled skutterudites and clathrate compounds, there has been no report on "rattling" oxides. Here we report the thermal properties of defect pyrochlore (β-pyrochlore) oxides with smaller cations in an oversized cage-like crystal structure. It is clearly shown that the thermal diffusivity, α and the thermal conductivity, κ, are lower for the oxides containing lighter A-site cations, contradicting the conventional prediction of the phonon thermal conductivity, in which lighter comprising atoms must give higher α and hence κ. These results strongly suggest that the smaller A-site cations with larger size mismatch to the surrounding cage structure enhance the phonon scattering and thereby reduce α and κ. These findings directly evidence the "rattling" effect of the loosely bound cations on the thermal transport properties of oxide materials.
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U2 - 10.1007/s11664-012-2382-1
DO - 10.1007/s11664-012-2382-1
M3 - Article
AN - SCOPUS:84879796125
VL - 42
SP - 1299
EP - 1302
JO - Journal of Electronic Materials
JF - Journal of Electronic Materials
SN - 0361-5235
IS - 7
ER -