Superconductivity and heavy fermions

Batlogg, B.; Bishop, D. J.; Bücher, E.; Golding, B.; Ramirez, A. P.; Fisk, Z.; Smith, James L.; Ott, H. R.

doi:10.1016/0304-8853(87)90632-9

Cited by 132 publications

(41 citation statements)

References 17 publications

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“…For H Ͻ 4 T in the PM state, the (T) data exhibit a local minimum at approximately 16 K (Fig. 5), while the (H) curves decrease with increasing H and (H ϭ 0) Ϫ (H) decreases rapidly as T increases; this behavior is consistent with the Kondo effect (15)(16)(17). To determine whether PrOs 4 As 12 , which shows Kondo lattice behavior, can be described in the PM regime by the single-ion Kondo impurity model, a scaling analysis developed by Schlottmann (18) was applied to the (H, T) data.…”

Section: Discussionsupporting

confidence: 63%

Field-dependent ordered phases and Kondo phenomena in the filled skutterudite compound PrOs₄As₁₂

Maple

Butch

Frederick

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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Electrical resistivity, specific heat, and magnetization measurements to temperatures as low as 80 mK and magnetic fields up to 16 T were made on the filled skutterudite compound PrOs4As12. The measurements reveal the presence of two ordered phases at temperatures below approximately 2.3 K and in fields below approximately 3 T. Neutron-scattering experiments in zero field establish an antiferromagnetic ground state <2.28 K. In the antiferromagnetically ordered state, the electronic-specific heat coefficient ␥ Ϸ 1 J͞mol⅐K 2 below 1.6 K and 0 < H < 1.25 T. The temperature and magnetic-field dependence of the electrical resistivity and specific heat in the paramagnetic state are consistent with single-ion Kondo behavior with a low Kondo temperature on the order of 1 K. The electronic-specific heat in the paramagnetic state can be described by the resonance-level model with a large zero-temperature electronic-specific heat coefficient that decreases with increasing magnetic field from approximately 1 J͞mol⅐K 2 at 3 T to approximately 0.2 J͞mol⅐K 2 at 16 T.heavy fermion ͉ Kondo effect ͉ antiferromagnetism T he compound PrOs 4 As 12 belongs to the family of filled skutterudites, which have the formula AT 4 X 12 , where A ϭ alkali metal, alkaline earth, lanthanide, or actinide, T ϭ Fe, Os, or Ir, and X ϭ P, As, or Sb. Because the ions reside in an atomic cage with a large number of X nearest neighbors, the hybridization between the lanthanide filler ion localized 4f states and the conduction-electron states is appreciable, often resulting in strongly correlated electron phenomena. In a recent article (1), we reported a study of the physical properties of single crystals of the filled skutterudite compound PrOs 4 As 12 between approximately 0.4 and 300 K by means of magnetization M, specific heat C, and electrical resistivity measurements. The previous study revealed that the compound exhibits two (possibly three) ordered phases below approximately 2.5 K in zero field and approximately 3 T at zero temperature from kinks in M as a function of magnetic field H and temperature T. Features in the (T) and C(T) data in zero field can be identified with transitions into the two ordered phases below 2.5 K. The magnetic susceptibility conforms to a Curie-Weiss law below approximately 20 K with an effective magnetic moment eff ϭ 2.77 B ͞formula unit consistent with a ⌫ 5 ground state in a cubic crystalline electric field and a cusp at approximately 2.5 K, indicative of antiferromagnetic (AFM) order. These results provide another example of the wide range of correlated electron ground states that are found in the Pr-based filled skutterudites, which include conventional (Bardeen, Cooper, Schrieffer) superconductivity (e.g., PrRu 4 Sb 12 ) (2), unconventional superconductivity (e.g., PrOs 4 Sb 12 ) (3, 4), heavy fermion behavior (e.g., PrFe 4 P 12 , PrOs 4 Sb 12 ) (5-8), antiferroquadrupolar order (e.g., PrFe 4 P 12 , PrOs 4 Sb 12 ), and magnetic order (e.g., PrFe 4 Sb 12 ) (9, 10). In this article, we report measurements of the te...

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Section: Discussionsupporting

confidence: 63%

Field-dependent ordered phases and Kondo phenomena in the filled skutterudite compound PrOs₄As₁₂

Maple

Butch

Frederick

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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“…Indeed, the low temperature resistive upturn is reminiscent of the Kondo effect in normal metals, and the B = 0 ρ(T) can be satisfactorily fitted (22) by the Kondo expression (38). However, the resistivity for a fixed number of Kondo compensated moments in a conventional metallic host scales with T/B (39,40), and so a different explanation is needed for the T/B 0.59 scaling found in YFe 2 Al 10 ( Fig. 5D).…”

mentioning

confidence: 91%

Quantum critical fluctuations in layered YFe ₂ Al ₁₀

Kim

Park

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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The absence of thermal fluctuations at T = 0 makes it possible to observe the inherently quantum mechanical nature of systems where the competition among correlations leads to different types of collective ground states. Our high precision measurements of the magnetic susceptibility, specific heat, and electrical resistivity in the layered compound YFe 2 Al 10 demonstrate robust field-temperature scaling, evidence that this system is naturally poised without tuning on the verge of ferromagnetic order that occurs exactly at T = 0, where magnetic fields drive the system away from this quantum critical point and restore normal metallic behavior.quantum criticality | ferromagnet | dynamical scaling T he interplay of competing interactions is responsible for the array of ground states that are possible in correlated electron systems. It is of particular importance to understand how one such ground state gives way to another when the system is tuned at temperature T = 0, without the complications of thermal fluctuations. Consequently, much interest has focused on quantum critical points (QCPs), where an ordered phase can be created by an infinitesimal modifications of pressure, composition, or field. The onset of ferromagnetic order is perhaps the simplest T = 0 phase transition, and indeed much experimental and theoretical effort has been directed toward understanding its essential features (1-6). It is generally believed that ferromagnetic order occurs at T = 0 via a discontinuous or first order transition, as is observed in the clean ferromagnets ZrZn 2 (7) and MnSi (8) under pressure. Disorder is known to render the ferromagnetic transition continuous, leading to the mean field behavior that is found when doping drives T C = 0 in Ni 1−x Pd x (9), Zr 1−x Nb x Zn 2 (10), and Nb 1−y Fe 2+y (11). More controversial is the possibility that strong quantum fluctuations, such as those that destabilize order in low-dimensional systems, may be significant near the T C = 0 ferromagnetic transition and perhaps may even destroy its first-order character (5). A complete experimental investigation of the critical phenomena and their scaling behaviors in a carefully selected system where disorder is minimal is needed to establish that quantum critical fluctuations are both present and relevant to the destabilization of ferromagnetic order.Progress toward obtaining this information has been painstaking, although a number of systems have been identified where the Curie temperature T C has been driven to zero. High pressure experiments evade the disorder that necessarily accompanies doping, but thus far only resistivity and susceptibility measurements have been reported. Complete experimental access is possible when doping is used to suppress T C → 0, but even small amounts of compositional inhomogeneity can obscure any intrinsic critical fluctuations of T C = 0 ferromagnetic transitions, resulting in interesting complications such as the Griffiths phase (12,13,14), as well as short ranged order, including spin glasses (15). Alterna...

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“…10). Below [1,13]. One important feature is that the magnetoresistivity of UBe13 is always negative in the whole range of fields and temperatures yet explored.…”

Section: Expérimental Set Upmentioning

confidence: 99%

“…1 figure 4 ; the value at 4.2 K was fixed so that p (H)/p (0) = 0.5 at H = 0.64 H*, as for spin 1/2 Kondo impurities [2]. The results of [1] [3] but is consistent with the data of [4] which g,ff = 3.4 J.LB between 300 K and 1 000 K. This is not too far from the free ion value of J = 4 (ILcff = 3.58 IL s) and J = 9/2 (ILeff = 3.62 g B). Between 150 K and 20 K, 1/X seems to follow a linear T dependence with 0 = -130 K (Fig.…”

Section: Expérimental Set Upmentioning

confidence: 99%

Normal and superconducting properties of UBe13

Brison¹,

Laborde²,

Jaccard³

et al. 1989

J. Phys. France

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Superconductivity and heavy fermions

Cited by 132 publications

References 17 publications

Field-dependent ordered phases and Kondo phenomena in the filled skutterudite compound PrOs₄As₁₂

Field-dependent ordered phases and Kondo phenomena in the filled skutterudite compound PrOs₄As₁₂

Quantum critical fluctuations in layered YFe ₂ Al ₁₀

Normal and superconducting properties of UBe13

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Superconductivity and heavy fermions

Cited by 132 publications

References 17 publications

Field-dependent ordered phases and Kondo phenomena in the filled skutterudite compound PrOs4As12

Field-dependent ordered phases and Kondo phenomena in the filled skutterudite compound PrOs4As12

Quantum critical fluctuations in layered YFe 2 Al 10

Normal and superconducting properties of UBe13

Contact Info

Product

Resources

About

Field-dependent ordered phases and Kondo phenomena in the filled skutterudite compound PrOs₄As₁₂

Field-dependent ordered phases and Kondo phenomena in the filled skutterudite compound PrOs₄As₁₂

Quantum critical fluctuations in layered YFe ₂ Al ₁₀