PREPARATION AND THERMOELECTRIC PROPERTIES OF THE SKUTTERUDITE-RELATEDPHASE RU0.5PD0.5SB3

A new skutterudite phase Ru0.5Pd0.5Sb3 was prepared. This new phase ad ds to a large number of already known materials with the skutterudite structure which have shown good potential for thermoelectric applicati ons. Single phase, polycrystalline samples were prepared and character ized by x-ray analysis, electron probe microanalysis, density, sound v elocity, thermal-expansion coefficient, and differential thermal analy sis measurements. Ru0.5Pd0.5Sb3 has a cubic lattice, space group Im3 ( T-h(5)), with a=9.298 Angstrom and decomposes at about 920 K. The Seeb eck coefficient, the electrical resistivity, the Hall effect, and the thermal conductivity were measured on hot-pressed samples over a wide range of temperatures. Preliminary results show that Ru0.5Pd0.5Sb3 beh aves as a heavily doped semiconductor with an estimated band gap of ab out 0.6 eV. The lattice thermal conductivity of Ru0.5Pd0.5Sb3 is subst antially lower than that of the binary isostructural compounds CoSb3 a nd IrSb3. The unusually low thermal conductivity might be explained by additional hole and charge transfer phonon scattering in this materia l. The potential of this material for thermoelectric applications is d iscussed. (C) 1996 American Institute of Physics.