Thermoelectric properties of Sn-filled skutterudites

Thermal conductivity, resistivity, Seebeck coefficient, and structure measu rements of CoSb3 with tin interstitially placed in the voids are reported. These tin-filled skutterudites were synthesized under high pressure and tem perature conditions; they cannot be synthesized under "normal" synthesis ap proaches. The tin atoms exhibit very large atomic displacement parameters i ndicating a large "rattling" motion inside their atomic "cages." The disord er induced by the Sn atoms is a very good phonon scattering mechanism. The thermal conductivity of these compounds is very low with a temperature depe ndence that is atypical of simple solids. The tin-filled compounds exhibit n-type semiconducting behavior with relatively high Seebeck coefficients fo r compounds whose electronic properties have not been optimized. The potent ial for thermoelectric applications is discussed. (C) 2000 American Institu te of Physics. [S0003-6951(00)02527-4].