Single crystals of AxBa8-xAl14Si 31 (A = Sr, Eu) were grown using a molten Al flux technique. Single-crystal X-ray diffraction confirms that AxBa 8-xAl14Si31 (A = Sr, Eu) crystallize with the type I clathrate structure, and phase purity was determined with powder X-ray diffraction. Stoichiometry was determined to be Sr0.7Ba 7.3Al14Si31 and Eu0.3Ba 7.7-Al14Si31 by electron microprobe analysis. These AxBa8-xAl14Si31 phases can be described as framework-deficient clathrate type I structures with the general formula, AxBa8-xAlySi42-3y/4 4-1/4y. DSC measurements indicate that these phases melt congruently at 1413 and 1415 K for Sr0.7Ba7.3Al14Si 31 and Eu0.3Ba7.7Al14Si 31, respectively. Temperature-dependent resistivity indicates metallic behavior, and the negative Seebeck coefficient indicates transport processes dominated by electrons as carriers. Thermal conductivity of these phases remains low with Sr0.7Ba7.3-Al14Si 31 having the lowest values.
ASJC Scopus subject areas
- Inorganic Chemistry