Slow crossover in YbXCu4 (X = AgCd, In, Mg, Tl, Zn) intermediate-valence compounds

Article

关键词: NEUTRON-SCATTERING;    RAY-ABSORPTION;    YBINCU4;    TRANSITION;    PHOTOEMISSION;    EXPANSION;    BEHAVIOR;   

DOI  :  10.1103/PhysRevB.63.054427

来源: SCIE

【 摘 要 】

We compare the results of measurements of the magnetic susceptibility chi (T), the linear coefficient of specific heat gamma (T) = C(T)/T, and 4f occupation number n(f)(T) for the intermediate-valence compounds YbXCu4 (X = Ag, Cd, In, Mg, Tl, Zn) to the predictions of the Anderson impurity model, calculated in the noncrossing approximation (NCA). The crossover from the low temperature Fermi-liquid state to the high-temperature local-moment state is substantially slower in the compounds than predicted by the NCA; this corresponds to the protracted screening recently predicted for the Anderson lattice. We present results for the dynamic susceptibility, measured through neutron-scattering experiments, to show that the deviations between theory and experiment are not due to crystal-field effects, and we present x-ray-absorption finestructure results that show the local crystal structure around the X atoms is well ordered, so that the deviations probably do not arise from Kondo disorder. The deviations may correlate with the background conduction electron density, as predicted for protracted screening.

【 授权许可】

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