Thermal properties of metamagnetic transition in heavy-fermion systems

Aoki, Yuji; Matsuda, Tatsuma D.; Sugawara, Hitoshi; Sato, Hideyuki; Ohkuni, Hitoshi; Settai, Rikio; ̄nuki, Y. O; Yamamoto, Etsuji; Haga, Yoshinori; Андреев, А.В.; Sechovský, V.; Havela, L.; Ikeda, Hiroaki; Miyake, Kazumasa

doi:10.1016/s0304-8853(97)00484-8

Cited by 91 publications

(43 citation statements)

References 26 publications

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“…The sign reversal for YbRh 2 Si 2 is present inside the AFM state and terminates at the critical field whereas the sign reversal for YbAgGe emerges at the critical field and persists up to high temperature. For CeRu 2 Si 2 , 35 the positive TEP in zero field also changes sign above the metamagnetic field for ⌬T ʈ c. Therefore, it is suggestive that the sign reversal can be an additional tool to probe and identify a QCP. Clearly, further theoretical and experimental investigations of this issue are required.…”

Section: Discussionmentioning

confidence: 93%

Thermoelectric power investigations of YbAgGe across the quantum critical point

2010

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The magnetic field and temperature dependences of the thermoelectric power (TEP) of the antiferromagnetically ordered heavy fermion compound YbAgGe are measured across the field-induced quantum critical point. These TEP measurements reproduce the earlier H-T phase diagram and identify an additional domelike phase between ∼45and ∼70 kOe. On the low-field side of this region, H>Hc∼45 kOe, the sign of the TEP changes from negative to positive; on the high-field side of this region, H≈70 kOe, a nonFermi-liquid state is evidenced as the logarithmic temperature dependence of S(T)/T, in agreement with previous specific heat results C(T)/T∝−log(T). For higher fields, H>70 kOe, the observed large value of α, S(T)=αT, is indicative of the heavy fermion state and shows a correlation with C(T)/T. Keywords Physics and Astronomy Disciplines Condensed Matter Physics CommentsThis article is from Physical Review B 82 (2010) The magnetic field and temperature dependences of the thermoelectric power ͑TEP͒ of the antiferromagnetically ordered heavy fermion compound YbAgGe are measured across the field-induced quantum critical point. These TEP measurements reproduce the earlier H-T phase diagram and identify an additional domelike phase between ϳ45 and ϳ70 kOe. On the low-field side of this region, H Ͼ H c ϳ 45 kOe, the sign of the TEP changes from negative to positive; on the high-field side of this region, H Ϸ 70 kOe, a non-Fermi-liquid state is evidenced as the logarithmic temperature dependence of S͑T͒ / T, in agreement with previous specific heat results C͑T͒ / T ϰ −log͑T͒. For higher fields, H Ͼ 70 kOe, the observed large value of ␣, S͑T͒ = ␣T, is indicative of the heavy fermion state and shows a correlation with C͑T͒ / T.

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Section: Discussionmentioning

confidence: 93%

Thermoelectric power investigations of YbAgGe across the quantum critical point

2010

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“…Note that this mechanism is different from the ordinary metamagnetism emerging when the magnetic field is applied to the Kondo state, which has been discussed as the origin of the metamagnetism observed in CeRu 2 Si 2 . [50][51][52][53][54][55][56] Namely, the present metamagnetism is caused by the field-induced QCP in the valence-crossover regime at h ¼ 0 (for moderate " f and not large U fc < U QCP fc in Fig. 7), while the ordinary one is caused in the Kondo regime (for deep " f and hence " n n f $ 1, see Fig.…”

Section: Effects Of Magnetic Field 331 Results By Slave-boson Mean-mentioning

confidence: 99%

Valence Fluctuations Revealed by Magnetic Field and Pressure Scans: Comparison with Experiments in YbXCu₄(X=In, Ag, Cd) and CeYIn₅(Y=Ir, Rh)

et al. 2009

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The mechanism of how critical end points of the first-order valence transition (FOVT) are controlled by a magnetic field is discussed. We demonstrate that critical temperature is suppressed to be a quantum critical point (QCP) by a magnetic field. This results explain the field dependence of the isostructural FOVT observed in Ce metal and YbInCu 4 . Magnetic field scan can make the system reenter in a critical valence fluctuation region. Even in intermediate-valence materials, the QCP is induced by applying a magnetic field, at which magnetic susceptibility also diverges. The driving force of the field-induced QCP is shown to be a cooperative phenomenon of the Zeeman effect and the Kondo effect, which creates a distinct energy scale from the Kondo temperature. The key concept is that the closeness to the QCP of the FOVT is vital in understanding Ce-and Yb-based heavy-fermions. This explains the peculiar magnetic and transport responses in CeYIn 5 (Y ¼ Ir, Rh) and metamagnetic transition in YbXCu 4 for X ¼ In as well as the sharp contrast between X ¼ Ag and Cd.

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“…6,13) Since the analysis of the CEF-level scheme, which well reproduces the anisotropy of the magnetic susceptibility, deduces that a hybridization node exists along the c-axis in β-YbAlB 4 , [13][14][15] we employ the anisotropic hybridization in the form of V k = V(1 −k 2 z ) witĥ k ≡ k/|k| to simulate β-YbAlB 4 most simply. The results are shown in Fig.…”

Section: Equation [Eq (6)] and Finally Obtain Y(t)mentioning

confidence: 99%

T/B Scaling in β-YbAlB₄

Watanabe

Miyake

2014

J. Phys. Soc. Jpn.

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The scaling behavior over four decades of the ratio of temperature T to magnetic field B observed in the magnetization in β-YbAlB 4 is theoretically examined. By developing a theoretical framework that exhibits the quantum critical phenomena of Yb-valence fluctuations under a magnetic field, we show that the T/B-scaling behavior can appear near the quan- Quantum critical phenomena in itinerant electron systems that do not follow the conventional spin-fluctuation theory [1][2][3][4] have attracted attention in condensed matter physics. 5) The heavy-electron metal β-YbAlB 4 has recently attracted great interest since the unconventional quantum criticality, such as the magnetic susceptibility χ ∼ T −0.5 , the electronic specific-heat coefficient C e /T ∼ − log T , and approximately T -linear resistivity, has been observed at low temperatures at least below 3 K down to a few hundred mK. 6,7) Interestingly, from the magnetization data for T < ∼ 3 K and the magnetic field B < ∼ 2 T, in β-YbAlB 4 it has been discovered that the magnetic susceptibility χ shows the following T/B scaling behavior over four decades of T/B:where µ B and k B are the Bohr magneton and Boltzmann constant, respectively, and ϕ is the function ϕ(x) = Λ(Γ 2 + x 2 ) 1/4 with Λ and Γ being constants. 7) Namely, χ −1 /(µ B B) 1/2 is expressed as a single scaling function of the ratio T/B.This striking behavior of Eq. (1) calls for theoretical explanation, and it has so far been proposed that anisotropic hybridization between f and conduction electrons is the key origin

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Thermal properties of metamagnetic transition in heavy-fermion systems

Cited by 91 publications

References 26 publications

Thermoelectric power investigations of YbAgGe across the quantum critical point

Thermoelectric power investigations of YbAgGe across the quantum critical point

Valence Fluctuations Revealed by Magnetic Field and Pressure Scans: Comparison with Experiments in YbXCu₄(X=In, Ag, Cd) and CeYIn₅(Y=Ir, Rh)

T/B Scaling in β-YbAlB₄

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Thermal properties of metamagnetic transition in heavy-fermion systems

Cited by 91 publications

References 26 publications

Thermoelectric power investigations of YbAgGe across the quantum critical point

Thermoelectric power investigations of YbAgGe across the quantum critical point

Valence Fluctuations Revealed by Magnetic Field and Pressure Scans: Comparison with Experiments in YbXCu4(X=In, Ag, Cd) and CeYIn5(Y=Ir, Rh)

T/B Scaling in β-YbAlB4

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Valence Fluctuations Revealed by Magnetic Field and Pressure Scans: Comparison with Experiments in YbXCu₄(X=In, Ag, Cd) and CeYIn₅(Y=Ir, Rh)

T/B Scaling in β-YbAlB₄