[Zurück]

St. Laumann, M. Ikeda, H. Sassik, A. Prokofiev, S. Paschen:
"Meltspun Ba₈Ga_16−xGe_30+x clathrates";
Journal of Materials Research, 26 (2011), 15; S. 1861 - 1865.

Ba8Ga16−xGe30+x is the clathrate with the highest thermoelectric figure of merit known to date. However, no p-type material could be obtained by conventional synthesis from the melt. Here we show that the time and cost-effective melt spinning technique can produce Ba8Ga16−xGe30+x in a metastable state, where x can be varied continuously from negative to positive values, resulting in both p- and n-type materials. The quenched phases were characterized by x-ray powder diffraction and transmission electron microscopy. It was surprising that they were perfectly crystalline, with large grain sizes of the order of a micrometer. Temperature dependent measurements of the electrical resistivity, Hall effect, thermopower, and thermal conductivity are presented and discussed in terms of a two-band model.

clathrates; thermoelectric; rapid solidification

http://dx.doi.org/10.1557/jmr.2011.184