Thermoelectric properties of layered perovskite-type (Sr1-x Cax) 3 (Ti1-y Nby) 2 O7

Kyu Hyoung Lee, Sung Wng Kim, Hiromichi Ohta, Kunihito Koumoto

Research output: Contribution to journalArticle

30 Citations (Scopus)

Abstract

The thermoelectric properties and crystallographic features of layered perovskite-type Ca-substituted (Sr1-x Cax) 3 (Ti1-y Nby) 2 O7 (y=0-0.2), Ruddlesden-Popper phases were investigated. The influence of crystal structure and carrier concentration on the carrier effective mass for Ti-based metal oxides based on TiO6 octahedra and having a significant Ca substitution effect are discussed. It was found from structural analysis that the large Seebeck coefficients of Ca-substituted compounds can be attributed to the high values of carrier effective mass, which originates from the enhancement of the symmetry of the TiO6 octahedra. Low thermal conductivities, 3.6-3.8 W m-1 K-1 at 300 K, were obtained for Ca-substituted compositions due to phonon scattering at SrO (SrTiO3) 2 interfaces of the inherent superlattice structure and to mass-defect phonon scattering between Ca (MCa =40) and Sr (MSr =88). The highest ZT value obtained was 0.15 at 1000 K, for 10 at % Ca-substituted Sr3 (Ti0.95 Nb0.05) 2 O7.

Original languageEnglish
Article number083707
JournalJournal of Applied Physics
Volume101
Issue number8
DOIs
Publication statusPublished - 2007 May 8

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Seebeck effect
scattering
structural analysis
metal oxides
thermal conductivity
substitutes
crystal structure
augmentation
defects
symmetry

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy (miscellaneous)
  • Physics and Astronomy(all)

Cite this

Lee, Kyu Hyoung ; Kim, Sung Wng ; Ohta, Hiromichi ; Koumoto, Kunihito. / Thermoelectric properties of layered perovskite-type (Sr1-x Cax) 3 (Ti1-y Nby) 2 O7. In: Journal of Applied Physics. 2007 ; Vol. 101, No. 8.
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abstract = "The thermoelectric properties and crystallographic features of layered perovskite-type Ca-substituted (Sr1-x Cax) 3 (Ti1-y Nby) 2 O7 (y=0-0.2), Ruddlesden-Popper phases were investigated. The influence of crystal structure and carrier concentration on the carrier effective mass for Ti-based metal oxides based on TiO6 octahedra and having a significant Ca substitution effect are discussed. It was found from structural analysis that the large Seebeck coefficients of Ca-substituted compounds can be attributed to the high values of carrier effective mass, which originates from the enhancement of the symmetry of the TiO6 octahedra. Low thermal conductivities, 3.6-3.8 W m-1 K-1 at 300 K, were obtained for Ca-substituted compositions due to phonon scattering at SrO (SrTiO3) 2 interfaces of the inherent superlattice structure and to mass-defect phonon scattering between Ca (MCa =40) and Sr (MSr =88). The highest ZT value obtained was 0.15 at 1000 K, for 10 at {\%} Ca-substituted Sr3 (Ti0.95 Nb0.05) 2 O7.",
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Thermoelectric properties of layered perovskite-type (Sr1-x Cax) 3 (Ti1-y Nby) 2 O7. / Lee, Kyu Hyoung; Kim, Sung Wng; Ohta, Hiromichi; Koumoto, Kunihito.

In: Journal of Applied Physics, Vol. 101, No. 8, 083707, 08.05.2007.

Research output: Contribution to journalArticle

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