Pd/Cu Site Interchange and Non-Fermi-Liquid Behavior in UCu_4Pd
  X-ray-absorption fine-structure measurements of the local structure in UCu_4Pd are described which indicate a probable lattice-disorder origin for non-Fermi-liquid behavior in this material. Short Pd-Cu distances are observed, consistent with 24 +/- 3% of the Pd atoms occupying nominally Cu sites. A "Kondo disorder" model, based on the effect on the local Kondo temperature T_K of this interchange and some additional bond-length disorder, agrees quantitatively with previous experimental susceptibility data, and therefore also with specific heat and magnetic resonance experiments. 
C. H. Booth, D. E. MacLaughlin, R. H. Heffner, R. Chau, M. B Maple,   and G. H. Kwei