Filled skutterudite antimonides: Electron crystals and phonon glasses

Journal Article · Mon Dec 01 04:00:00 EST 1997 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.56.15081· OSTI ID:554367

Sales, B C; Mandrus, D; Chakoumakos, B C; Keppens, V; Thompson, J R ^[1]

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1. Solid State Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

Crystallographic data, electrical and thermal transport measurements, and magnetic susceptibility values are reported for several compounds and alloys with the filled skutterudite structure, R{sub 1{minus}y}Fe{sub 4{minus}x}Co{sub x}Sb{sub 12} (R=La, Ce, or Th; 0{lt}y{lt}1; x=0,1). Room-temperature velocity of sound data is also reported. These materials are of interest because of their potential in thermoelectric power generation and refrigeration applications. The transport properties of both filled and unfilled skutterudite compounds are analyzed using standard semiconductor transport models. Filled skutterudite antimonides appear to be a good approximation of an idealized solid with the good electrical transport properties of a crystal but the poor heat conduction characteristics of a glass. The incoherent rattling of the weakly bound rare-earth atoms in these materials lowers the thermal conductivity at room temperature to values comparable to that of vitreous silica. Relative to the analogous unfilled compounds, the filled skutterudites exhibit larger effective masses and smaller mobilities. Good overall electrical transport is maintained, however, as evidenced by values for the figure of merit (ZT) greater than 1 at elevated temperatures (700{endash}1000 K). Above room temperature, there is very little difference in the electrical and thermal transport behavior between the La and Ce filled compounds. The effects of the hybridization caused by the proximity of the Ce 4f level to the Fermi energy, however, are evident at temperatures below 300 K. {copyright} {ital 1997} {ital The American Physical Society}

• Research Organization: Oak Ridge National Laboratory
• DOE Contract Number: AC05-96OR22464
• OSTI ID: 554367
• Journal Information: Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 23 Vol. 56; ISSN 0163-1829; ISSN PRBMDO
• Country of Publication: United States
• Language: English

Related Subjects

30 DIRECT ENERGY CONVERSION
ANTIMONIDES
CARRIER MOBILITY
CERIUM ALLOYS
COBALT ALLOYS
COBALT COMPOUNDS
CRYSTAL STRUCTURE
EFFECTIVE MASS
ELECTRIC CONDUCTIVITY
FERMI LEVEL
IRON ALLOYS
IRON COMPOUNDS
LANTHANUM ALLOYS
MAGNETIC SUSCEPTIBILITY
PHONONS
PHYSICAL PROPERTIES
RARE EARTH COMPOUNDS
SEMICONDUCTOR MATERIALS
THERMAL CONDUCTIVITY
THERMOELECTRIC MATERIALS
THERMOELECTRIC REFRIGERATORS
THORIUM ALLOYS