Abstract
We examine the effect of alloying Sn on the Sb site of ytterbium-filled skutterudites, a promising class of thermoelectric materials. We report measurements of the Hall effect, electrical resistivity, Seebeck coefficient, and thermal conductivity between 2 and 300 K on two series of samples having different ytterbium filling fractions: with 0.05, 0.1, and 0.2, and with 0.6, 0.8, 0.83, and 0.9. We find that the substitution of Sn does not lower the electron concentration of these samples, but rather gives rise to a p-type carrier. Hall measurement data for can be understood in the context of two-carrier electrical conduction. Although the thermal conductivity of these ytterbium-filled skutterudites is significantly suppressed from that of the unfilled it is nearly independent of the Sn concentration. The role of phonon-point defect scattering and phonon resonance scattering in reducing the lattice thermal conductivity of the Yb-filled samples is assessed by a theoretical model.
- Received 20 June 2002
DOI:https://doi.org/10.1103/PhysRevB.67.165207
©2003 American Physical Society