Effect of Al substitution on the thermoelectric properties of the type VIII clathrate Ba 8Ga 16Sn 30

S. K. Deng, Y. Saiga, Koichiro Suekuni, T. Takabatake

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7 Citations (Scopus)

Abstract

Single-crystal samples of the type VIII clathrate Ba 8Ga 16-x Al x Sn 30 (0 ≤ x ≤ 12) were prepared by the Sn-flux method, and the structural and electrical properties were studied from 300 K to 600 K. The lattice parameter increases linearly as x is increased from 0 to 10.5, which is the solubility limit of Al. For all samples, the electrical conductivity σ decreases monotonically as the temperature is increased. σ(T = 300 K) increases from 1.88 × 10 4 S/m for x = 0 to 3.03 × 10 4 S/m for x = 2, and then gradually decreases to 2.4 × 10 4 S/m with further increase of x to 8. The increase of σ for Al-substituted samples is attributed to enhancement of carrier mobility. The Seebeck coefficients of samples with 0 ≤ x ≤ 8 are negative with large values, and the absolute values increase from 240 μV/K to 320 μV/K as the temperature increases from 300 K to 600 K. At 300 K, the effective mass m*/m 0 is in the range from 0.53 to 0.67, and the samples with x = 6 and x = 8 have a rather low thermal conductivity of 0.72 W/mK and 0.78 W/mK, respectively. ZT reaches 1.2 at 500 K for x = 6.

Original languageEnglish
Pages (from-to)1124-1128
Number of pages5
JournalJournal of Electronic Materials
Volume40
Issue number5
DOIs
Publication statusPublished - May 1 2011
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering
  • Materials Chemistry

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