Crossover from First-Order Valence Transition to Kondo Behavior in C15b-Type YbCu5-xInxSystem

He, Junhui; Tsujii, Naohito; Yoshimura, Kazuyoshi; Koyamada, Koji; Goto, T.

doi:10.1143/jpsj.66.2481

Cited by 21 publications

(6 citation statements)

References 19 publications

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“…This is also confirmed by our recent results for the isostructural YbCu 5Ϫx In x systems. 35 In this system, an In atom on a 4c site is replaced by a Cu atom, while the Yb sublattice preserves the face-centered-cubic structure, in contrast to a substitution like Yb 1Ϫx In x Cu 2 . In YbCu 5Ϫx In x , the valence transition is rapidly broadened by a faint substitution of Cu.…”

Section: Resultsmentioning

confidence: 99%

Kondo-lattice formation in cubic-phaseYbCu5

Tsujii

Amita

et al. 1997

Phys. Rev. B

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The YbCu 5 phase with C15b structure has been prepared by a high-pressure technique, and its physical properties have been investigated. The temperature dependence of magnetic susceptibility, electrical resistivity, and specific heat show Kondo-lattice formation. Furthermore, a heavy Fermi-liquid state without magnetic ordering down to 2.0 K is found to evolve below about 6 K. The electronic specific heat coefficient ␥ is enhanced to values as large as to 550 mJ/mol K 2 . The magnetization measured up to 40 T at 1.6 K has a field dependence which is expected for a Kondo system when the total angular momentum is JϾ1. All results are in good agreement with the extrapolation of the previous results of YbCu 5Ϫx Ag x (0.125рxр1.0) for x→0. The concentration dependence of characteristic temperatures of YbCu 5Ϫx Ag x can be quantitatively explained by the chemical pressure effect within the compressible Kondo model for the full range of Ag concentration ͑ 0.0рxр1.0). The origins of Kondo-lattice formation in YbCu 4 Ag and the valence transition in YbCu 4 In are discussed.

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Section: Resultsmentioning

confidence: 99%

Kondo-lattice formation in cubic-phaseYbCu5

Tsujii

Amita

et al. 1997

Phys. Rev. B

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“…The primary goal of the XAFS measurements was to determine whether X/Cu site interchange is significant in these compounds. Such disorder is a real possiblity given that YbCu 5 can grow in the C15b structure, 23 and given that UPdCu 4 , which also grows in the C15b struucture, has been shown to have significant Pd/Cu site interchange. 24 Our earlier neutron diffraction measurements 25 of flux-grown crystals of YbInCu 4 , coupled with Rietveld refinement, suggest the average crystal structure is very well ordered.…”

Section: B Xafsmentioning

confidence: 99%

Slow crossover inYbXCu4(X=Ag, Cd, In, Mg, Tl, Zn) intermediate-valence compounds

Lawrence

Riseborough²,

Booth³

et al. 2001

Phys. Rev. B

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We compare the results of measurements of the magnetic susceptibility χ(T ), the linear coefficient of specific heat γ(T ) = C(T )/T and 4f occupation number n f (T ) for the intermediate valence compounds YbXCu 4 (X = Ag, Cd, In, Mg, Tl, Zn) to the predictions of the Anderson impurity model, calculated in the non-crossing 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 fine-structure (XAFS) 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.

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“…Recently a strong emphasis was given to the investigation of the solid solutions YbCu 5Àx M x (M ¼ Ag, Au, In) crystallizing in the cubic AuBe 5 -type structure, where the substitution of Cu by M offers the possibility to study the different evolution of ground state properties depending on the M element, starting from dense Kondo behaviour for low xvalues. In fact, whereas YbCu 5Àx Ag x exhibits Kondo lattice behaviour in the whole substitution range 0 < x 1, Cu/In and Cu/Au substitutions drive the system through a crossover to a valence fluctuation system [1] and to long-range magnetic order [2,3], respectively. In particular, for the YbCu 5Àx Au x system a quantum phase transition seems to occur, although an agreement on the precise location of the quantum critical point (QCP) has still to be found (x c ¼ 0.2e0.4 [3], x c ¼ 0.5 [2]).…”

Section: Introductionmentioning

confidence: 99%