Wei Kaya, Zeng Xiaoyu, Tritt Terry M, Khabibullin Artem R, Woods Lilia M, Nolas George S
Department of Physics, University of South Florida, Tampa, FL 33620, USA.
Department of Physics and Astronomy, Clemson University, Clemson, SC 29634, USA.
Materials (Basel). 2016 Aug 26;9(9):732. doi: 10.3390/ma9090732.
Tin clathrate-II framework-substituted compositions are of current interest as potential thermoelectric materials for medium-temperature applications. A review of the literature reveals different compositions reported with varying physical properties, which depend strongly on the exact composition as well as the processing conditions. We therefore initiated an approach whereby single crystals of two different (K,Ba)(Ga,Sn) compositions were first obtained, followed by grinding of the crystals into fine powder for low temperature spark plasma sintering consolidation into dense polycrystalline solids and subsequent high temperature transport measurements. Powder X-ray refinement results indicate that the hexakaidecahedra are empty, K and Ba occupying only the decahedra. Their electrical properties depend on composition and have very low thermal conductivities. The structural and transport properties of these materials are compared to that of other Sn clathrate-II compositions.
笼形包合物-II骨架取代的锡基组合物作为中温应用的潜在热电材料目前备受关注。文献综述表明，已报道的不同组合物具有不同的物理性质，这些性质强烈依赖于确切的组成以及加工条件。因此，我们采用了一种方法，首先获得两种不同的(K,Ba)(Ga,Sn)组合物的单晶，然后将晶体研磨成细粉，通过低温放电等离子烧结固结为致密的多晶固体，并随后进行高温输运测量。粉末X射线精修结果表明，十六面体是空的，K和Ba仅占据十面体。它们的电学性质取决于组成，并且具有非常低的热导率。将这些材料的结构和输运性质与其他笼形包合物-II锡基组合物的性质进行了比较。
