Preparation and Characterization of Sr, Ba Filled Type-I Ge Clathrate Single Crystals
Sr or Ba filled type-I Ge clathrate single crystals were prepared using high pure elemental Ga, Ge, and Sr or Ba as the starting materials, and Ga as a flux. Powder X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), differential scanning calorimeter (DSC) were used to characterize the crystals, respectively. The results show that large and well-crystallized single crystals can be prepared under optimum synthesis condition. The composition of the crystals is in good agreement with the nominal composition (M8Ga16Ge30, M=Sr, Ba). Raman spectra of the single crystals were studied at room temperature and several of the Raman active vibrational modes in the crystals have been identified.
Wei Pan and Jianghong Gong
K. F. Cai et al., "Preparation and Characterization of Sr, Ba Filled Type-I Ge Clathrate Single Crystals", Key Engineering Materials, Vols. 336-338, pp. 896-899, 2007