Crystallographic evidence for chemical ordering in UCu{sub 5{minus}x}Pd{sub x}
- Department of Physics and the Institute for Pure and Applied Physical Sciences, University of California, San Diego, California 92093 (United States)
- Manuel Lujan Jr. Neutron Scattering Center, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
We report elastic neutron-diffraction measurements on UCu{sub 5{minus}x}Pd{sub x} (x=0.65, 1.0, and 1.5) using the High-Intensity Powder Diffractometer instrument at the Los Alamos Neutron Science Center. Data from six detector banks were simultaneously refined using Rietveld analysis. From the refinements of the data, we find that for Pd concentrations x{lt}1, Pd atoms preferentially occupy the minority Cu/Pd 4c sites, and Cu atoms fully occupy the majority Cu/Pd 16e sites. For Pd concentrations x{gt}1, Pd atoms fully occupy the minority sites and a mixture of Cu and Pd atoms occupy the 16e sites. At the special concentration x=1, we find that the Pd and Cu atoms occupy separate crystallographic sites. This arrangement of atoms is indicative of chemical ordering, although no superlattice peaks were observed. The implications of chemical ordering in UCu{sub 5{minus}x}Pd{sub x} on disorder-driven models of non-Fermi-liquid behavior will be discussed. {copyright} {ital 1998} {ital The American Physical Society}
- OSTI ID:
- 636179
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 58, Issue 1; Other Information: PBD: Jul 1998
- Country of Publication:
- United States
- Language:
- English
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