Abstract Details 167

EXAFS Analysis of Sb doped CePt4Ge12
Abstract ID 167
Presenter Patrick Nast
Presentation Type Poster
Full Author List Frank Bridges, John Wilde

University of California, Santa Cruz


We investigated the local structure of the Sb doped skutterudite CePt4Ge12−xSbx using extended x-ray absorption fine structure (EXAFS) analysis. CePt4Ge12−xSbx belongs to a class of materials that are currently studied for their potential thermoelectric properties. Prior analysis of CePt4Ge12 suggests that Ce may behave like a "rattler" atom in a cage, leading to a lower thermal conductivity in the material. We present a comparison of EXAFS analyses at different Sb doping levels for the Ce LIII and Pt LIII edges over a temperature range of 5-300 K. We found that the EXAFS for Ce LIII became significantly disordered with increasing Sb concentration, and for x = 3 the nearest neighbor peak (Ce-Ge) is no longer observed. The Pt nearest neighbors, however, have little disorder even at x = 3. This suggests anisotropic distortions, most likely in the plane formed by the Ce-Ge bonds and the Ge rings, which decrease the lattice thermal conductivity at low temperatures. Further research may investigate whether Sb doping pushes the rattler off-center, and more analysis at high doping levels may shed light on this material’s candidacy for thermoelectric applications.



Funding Acknowledgement