The ambivalence of Yb in YbAl2 and YbAl3

Havinga, E.; Buschow, K.H.J.; Daal, H.J. van

doi:10.1016/s0038-1098(73)80026-2

Cited by 134 publications

(36 citation statements)

References 10 publications

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“…19 Therefore, the Yb 2+ -4f 7/2 peak can be identified as the Kondo resonance peak, thereby providing conclusive evidence for Kondo screening in YbAl 2 and consistency with the T max behavior in the magnetic susceptibility. 13,18 This finding establishes that the coherent Kondo ground state can be robust even in a nearly divalent regime.…”

Section: +mentioning

confidence: 52%

“…However, Yb 2+ and Yb 3+ components in spectra are rela- 10 For YbAl 2 , the sharp rise at low T in the magnetic susceptibility has also been attributed to the surface Yb 2 O 3 as an impurity. 13,15,18 In our HAXPES measurements using in-situ-fractured single crystals of YbAl 2 , no O-1s signal has been detected. Therefore, the major difference in estimating Yb valence using XAS and our HAXPES results can be due to the surface oxidation of powder samples in XAS.…”

Section: +mentioning

confidence: 56%

“…[14][15][16] The magnetic susceptibility has a broad maximum (T max ) at 800-850 K and is nearly independent of T below 300 K after subtracting the impurity contribution. 13,15,17,18 The Kondo T (T K ) has been estimated as 2000-2600 K from the 3T max or the inelastic neutron scattering. 19 The Yb valence has been investigated by some techniques such as the lattice parameters 17,20 and the x-ray absorption spectroscopy (XAS) at the Yb-L III edge.…”

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confidence: 99%

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Photoemission Evidence for Valence Fluctuations and Kondo Resonance in YbAl₂

et al. 2012

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We use hard x-ray photoemission spectroscopy (HAXPES) to investigate the electronic structure of YbAl2, for which the Yb valence has not been consistently reported to date. The bulk sensitivity and the analytical simplicity provided by the Yb 3d core-level HAXPES allow a reliable determination of the mean valence of Yb ions. For YbAl2, it is evaluated to be +2.20, which remains nearly unchanged below 300 K. The Kondo resonance peak with an extremely high Kondo temperature (above 2000 K) is clearly identified in the valence-band spectra. The results indicate that a coherent Kondo state can be robust even in a nearly divalent system.

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confidence: 52%

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confidence: 56%

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confidence: 99%

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Photoemission Evidence for Valence Fluctuations and Kondo Resonance in YbAl₂

et al. 2012

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“…At ¼ 40 , a broad hump of the magnetoresistance appears at approximately 60 kOe. Interestingly, this hump changes to a clear peak at H Q ' 60 kOe for ¼ 54: 7 , i.e., for H k h111i. Upon further increasing the field angle , the peak at H Q slightly shifts to higher fields and disappears at approximately ¼ 80…”

Section: Electrical Resistivity Under Magnetic Fieldsmentioning

confidence: 96%

“…5) The lattice constant of these compounds is very large, i.e., a $ 14 # A, and thus the distance between Yb-Yb atoms is large, more than 6 # A, compared with a ¼ 4:20 # A in YbAl 3 with the AuCu 3 -type cubic structure. 6) YbAl 3 is an intermediate-valence compound, where the magnetic susceptibility possesses a maximum at a relatively high temperature T max ¼ 120 K. [7][8][9] Here, T max roughly corresponds to the Kondo temperature. The electronic specific heat coefficient is fairly large, i.e., 58 mJ/(K 2 Ámol).…”

Section: Introductionmentioning

confidence: 99%

Field-Induced Quadrupolar Ordered Phase for H∥<111> in Heavy-Fermion Compound YbCo₂Zn₂₀

et al. 2011

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Magnetic susceptibility, high-field magnetization up to 500 kOe, and specific heat in a wide temperature range from 0.06 to 300 K were measured for single crystals of the cubic heavy-fermion compound YbCo 2 Zn 20 in order to elucidate the electronic states of the compound at low temperatures. A strong increase in the magnetic specific heat in the form of C mag =T below $1 K is approximately explained by the resonant level model for S ¼ 1=2 with the Kondo temperature T K ¼ 1 K, and an extremely large C mag =T ' 8 J/(K 2 Ámol) below about 0.2 K is explained by considering the magnetic entropy of the doublet ground state in the 4f crystalline electric field (CEF) scheme of an Yb 3þ ion, which corresponds to an extremely large electronic specific heat coefficient. The field-induced ordered phase for H k h111i, which has recently been found by low-temperature magnetization measurements, was precisely studied by electrical resistivity and specific heat measurements, and was observed in a limited angular range around the h111i direction. On the basis of CEF analyses, the level crossing of the two lowest CEF states is essentially important to understand the field-induced ordered phase, which can be reduced to a field-induced antiferro-quadrupolar ordering based on the À 3 -type quadrupole moment O 0 2 .

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