A. Miller, F. Bridges, T.Keiber

UCSC Physics

Skutterudites are a class of thermoelectric materials where a rare earth atom acts a "rattler" in a semi-rigid cage of atoms, lowering the thermal conductivity. With different choices of the cage atoms, or partial filling of the rare earth site, the efficiency of these devices make them candidates for thermoelectric applications such as solid state refigeration and utilization of waste heat. The extended x-ray absorption fine structure (EXAFS) technique is used to investigate the local structure of all atomic edges of this system. The skutterudite Ce_0.9Fe₃CoSb₁₂ has high disorder for the Ce-Sb pair when Co is doped onto the Fe site and the Ce site is partially filled. This doping causes the disorder for the Ce-Sb₄ chain to increase. The disorder of Ce_0.9Fe₃CoSb₁₂ is also compared with similar results to the disorder of the previously analzed skutterudite DDyFe_4-xNi_xSb₁₂.