naa a22 4500 510802362 CHVBK 20180411083401.0 cr unu---uuuuu 180411e20130701xx s 000 0 eng 10.1007/s11664-012-2382-1 doi (NATIONALLICENCE)springer-10.1007/s11664-012-2382-1 Extremely Low Thermal Conductivity in Oxideswith Cage-Like Crystal Structure [Elektronische Daten] [Michitaka Ohtaki, So Miyaishi] 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. TMS, 2013 Lattice thermal conductivity nationallicence rattling nationallicence thermal diffusivity nationallicence β -pyrochlore nationallicence oxide thermoelectric material nationallicence phonon mean free path nationallicence Ohtaki Michitaka Department of Molecular and Material Sciences, Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, 6-1 Kasugakouen, 816-8580, Kasuga, Fukuoka, Japan aut Miyaishi So Department of Molecular and Material Sciences, Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, 6-1 Kasugakouen, 816-8580, Kasuga, Fukuoka, Japan aut Journal of Electronic Materials Springer US; http://www.springer-ny.com 42/7(2013-07-01), 1299-1302 0361-5235 42:7<1299 2013 42 11664 https://doi.org/10.1007/s11664-012-2382-1 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11664-012-2382-1 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Ohtaki Michitaka Department of Molecular and Material Sciences, Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, 6-1 Kasugakouen, 816-8580, Kasuga, Fukuoka, Japan aut NATIONALLICENCE 700 1- Miyaishi So Department of Molecular and Material Sciences, Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, 6-1 Kasugakouen, 816-8580, Kasuga, Fukuoka, Japan aut NATIONALLICENCE 773 0- Journal of Electronic Materials Springer US; http://www.springer-ny.com 42/7(2013-07-01), 1299-1302 0361-5235 42:7<1299 2013 42 11664 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer