Chapter 1 Heavy fermions and related compounds

Nieuwenhuys, G. J.

doi:10.1016/s1567-2719(05)80005-8

Cited by 15 publications

(10 citation statements)

References 346 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Intermetallic cerium compounds have attracted widespread attention in recent years because of their puzzling physical properties such as long-range magnetic ordering, Kondo effects, magnetic ordering with anomalously high ordering temperatures, the coexistence of heavy-fermion behavior and superconductivity or valence fluctuation behavior. − The reason for these unusual properties is mostly the hybridization of the 4f electrons with the conduction electrons. Most compounds with cerium in the stable trivalent oxidation state ([Xe]4f 1 configuration) show antiferromagnetic ordering at low temperature, while only few compounds order ferromagnetically.…”

Section: Introductionmentioning

confidence: 99%

“…Most compounds with cerium in the stable trivalent oxidation state ([Xe]4f 1 configuration) show antiferromagnetic ordering at low temperature, while only few compounds order ferromagnetically. The recent investigations have mainly focused on compounds with the simple compositions CeTX and CeT 2 X 2 ( T = transition metal; X = element of the p block). − Most of these compounds have highly symmetric structures. This facilitates the understanding of the physical properties and the theoretical treatment.…”

Section: Introductionmentioning

confidence: 99%

“…The recent investigations have mainly focused on compounds with the simple compositions CeTX and CeT 2 X 2 (T ) transition metal; X ) element of the p block). [1][2][3] Most of these compounds have highly symmetric structures. This facilitates the understanding of the physical properties and the theoretical treatment.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The Stannides LaRhSn₂ and CeRhSn₂

Niepmann¹,

Pöttgen²,

Künnen³

et al. 1999

Chem. Mater.

View full text Add to dashboard Cite

The new stannides LaRhSn2 and CeRhSn2 have been prepared in quantitative yield by reacting the elements in an arc-melting furnace and subsequent annealing at 970 K. Their structures were determined from X-ray single crystal and powder data: Cmcm, a = 460.3(2) pm, b = 1702.9(7) pm, c = 961.3(3) pm, wR2 = 0.0513, 1317 F 2 values, 30 variables for a CeRhSn2 single crystal and a = 463.9(1) pm, b = 1710.0(3) pm, c = 963.7(2) pm, R F = 3.25, 247 F values, 25 parameters for a LaRhSn2 powder sample. Striking structural motifs of LaRhSn2 and CeRhSn2 are distorted RhSn5 square pyramids which are condensed via common tin atoms and via Sn−Sn bonds forming a three-dimensional infinite [RhSn2] polyanion. The latter is characterized by strong Rh−Sn (262−277 pm) as well as Sn−Sn (281 pm) interactions. The cerium atoms fill distorted pentagonal and hexagonal channels within the polyanion. Both crystallographically independent cerium atoms have high coordination numbers: 4Ce + 6Rh + 9Sn for Ce1 and 6Ce + 4Rh + 10Sn for Ce2. Magnetic susceptibility measurements indicate Pauli paramagnetism for LaRhSn2 and Curie−Weiss behavior (2.56(2) μB/Ce) for CeRhSn2. At 4.0(2) K, CeRhSn2 orders ferro- or ferrimagnetically. The experimental saturation magnetization is 0.75(2) μB/Ce at 5.5 T and 2 K. LaRhSn2 and CeRhSn2 are metallic conductors with room-temperature values of 85 ± 20 μΩ cm (LaRhSn2) and 100 ± 20 μΩ cm (CeRhSn2) for the resistivity. The resistance of CeRhSn2 shows a broad minimum near 30 K, possibly suggesting some Kondo-type interactions. Despite the three crystallographically different tin sites the 119Sn Mössbauer spectroscopic measurements show only one signal at δ = 1.93(1) mm/s (LaRhSn2) and δ = 2.01(2) mm/s (CeRhSn2), subjected to quadrupole splitting of ΔE Q = 1.29(1) mm/s (LaRhSn2) and ΔE Q = 1.38(2) mm/s (CeRhSn2).

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The Stannides LaRhSn₂ and CeRhSn₂

Niepmann¹,

Pöttgen²,

Künnen³

et al. 1999

Chem. Mater.

View full text Add to dashboard Cite

show abstract

“…Basically, HF metals consist of a lattice of atoms with localized (f-)electrons, where the magnetism is quenched by a coherent Kondo effect. This leads to a strong peak in the DOS near the Fermi energy with small energy width (for relevant reviews, see [5,6]). The consequences for the low-temperature physics can be phenomenologically described in terms of Landau Fermi liquid theory by a mass renormalization of the charge carriers.…”

mentioning

confidence: 99%

Proximity effects in the superconductor/heavy-fermion bilayer system Nb/CeCu ₆

et al. 2003

View full text Add to dashboard Cite

Abstract. -We have investigated the proximity effect between a superconductor (Nb) and a 'Heavy Fermion' system (CeCu6) by measuring critical temperatures Tc and parallel critical fields H c2 (T) of Nb films with varying thickness deposited on 75 nm thick films of CeCu6, and comparing the results with the behavior of similar films deposited on the normal metal Cu. For Nb on CeCu6 we find a strong decrease of Tc with decreasing Nb thickness and a finite critical thickness of the order of 10 nm. Also, dimensional crossovers in H c2 (T) are completely absent, in strong contrast with Nb/Cu. Analysis of the data by a proximity effect model based on the Takahashi-Tachiki theory shows that the data can be explained by taking into account both the high effective mass (or low electronic diffusion constant), and the large density of states at the Fermi energy which characterize the Heavy Fermion metal.

show abstract

“…4). These values are large compared to other U compounds that form in the related ThCr 2 Si 2 structure [15]. Around 26 K, r a 0 and r b exhibit an upward step at T ord .…”

mentioning

confidence: 82%