Preparation and thermoelectric properties of some phosphide skutterudite compounds

Thermoelectric properties of CoP3 and CeFe4P12 have been measured. These compounds were synthesized by a flux technique using Sn as the solvent. The samples were characterized by x-ray diffractometry and electron microprobe analyses. The Seebeck coefficient, the electrical resistivity, the Hall effect, and the thermal conductivity were measured over a wide range of temperatures. The results indicate that CoP3 and CeFe4P12 are semiconductors, in agreement with theoretical predictions. The thermal conductivity of CeFe4P12 is about 10 times larger than that for CeFe4Sb12 which is primarily due to both reduced motion of the Ce ions in smaller voids and lower hole-phonon scattering. The results are analyzed and discussed to provide guidelines for optimization of the thermoelectric properties of these materials. (C) 1999 American Institute of Physics. [S0021-8979(99)03923-7].