Effects of lattice disorder in the UCu5-xPdx system

Article

关键词: FERMI-LIQUID BEHAVIOR;    GRIFFITHS PHASE;    ELECTRONIC-STRUCTURE;    MAGNETIC-PROPERTIES;    KONDO DISORDER;    TEMPERATURE;    ALLOYS;    HEAT;   

DOI  :  10.1103/PhysRevB.65.245114

来源: SCIE

【 摘 要 】

The UCu5-xPdx system exhibits non-Fermi liquid (NFL) behavior in thermodynamic and transport properties at low temperatures for Pd concentrations 0.9less than or similar toxless than or similar to1.5. The local structure around the U, Cu, and Pd atoms has been measured for 0less than or equal toxless than or equal to1.5 using the x-ray absorption fine structure technique in order to quantify the effects of lattice disorder on the NFL properties. A model which allows a percentage of the Pd atoms to occupy nominal Cu (16e) sites s was used to fit the Pd and Cu K edge and U L-III edge data. Pd/Cu site interchange was found to occur in all samples (xnot equal0), reaching a minimum value of ssimilar to0.17 at x=0.7 and increasing monotonically to ssimilar or equal to0.4 at x=1.5. These data also determine an upper limit on the static disorder of the nearest-neighbor U-Cu pairs. A single-ion Kondo disorder model with a lattice-disorder origin of the distribution of f/conduction electron hybridization strengths within a tight-binding approach is used to calculate magnetic susceptibility. The results indicate that the measured U-Cu static disorder is not sufficient to explain the NFL behavior of the magnetic susceptibility within this variant of the Kondo disorder model, suggesting either that other sources of Kondo disorder exist or that the Kondo disorder model is not applicable to UCu5-xPdx.

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