High temperature thermoelectric transport properties of double-atom-filled clathrate compounds Yb{sub x}Ba{sub 8-x}Ga{sub 16}Ge{sub 30}

Journal Article · Tue Jul 01 00:00:00 EDT 2008 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.2951888· OSTI ID:21137383

Xinfeng, Tang; Peng, Li; Shukang, Deng; Qingjie, Zhang ^[1]

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1. State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China)

Type-I clathrates Yb{sub x}Ba{sub 8-x}Ga{sub 16}Ge{sub 30} (x=0-1.3) filled by ytterbium and barium were synthesized by melting reaction method combined with spark plasma sintering method. The structure and thermoelectric properties of double-atoms-filled clathrate compounds are investigated. X-ray diffraction patterns and Rietveld analysis reveal that the compounds prepared by this method are type-I clathrates. The filling atoms exhibit atomic displacement parameters that are larger than that of framework atoms. All specimens show n-type conduction and the room temperature carrier concentration (N{sub p}) increases with the increasing Yb content. The electrical conductivity of the compounds increases at first and then decreases with the increasing Yb content. When x=0.7, it reaches the maximum. The Seebeck coefficient decreases gradually with the increasing x. The substituting of Yb atoms for Ba leads to significant influence on the lattice thermal conductivity of the compounds. The lattice thermal conductivity decreases gradually with the increasing x. Of all the Yb{sub x}Ba{sub 8-x}Ga{sub 16}Ge{sub 30} compounds, Yb{sub 0.5}Ba{sub 7.5}Ga{sub 16}Ge{sub 30} compound has the greatest ZT value and its maximal ZT value reaches 1.1 at about 950 K. Compared with the Ba{sub 8}Ga{sub 16}Ge{sub 30} sample, it increases by 90% at the same temperature.

• OSTI ID: 21137383
• Journal Information: Journal of Applied Physics, Vol. 104, Issue 1; Other Information: DOI: 10.1063/1.2951888; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ATOMIC DISPLACEMENTS
BARIUM
BARIUM COMPOUNDS
CARRIER DENSITY
CLATHRATES
ELECTRIC CONDUCTIVITY
GALLIUM COMPOUNDS
GERMANIUM COMPOUNDS
MELTING
PLASMA
SEEBECK EFFECT
SINTERING
TEMPERATURE RANGE 0273-0400 K
TEMPERATURE RANGE 0400-1000 K
THERMAL CONDUCTIVITY
THERMOELECTRIC PROPERTIES
X-RAY DIFFRACTION
YTTERBIUM
YTTERBIUM COMPOUNDS