Magnetic properties of the filled skutterudite-type structure compounds<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">GdRu</mml:mi></mml:mrow><mml:mrow><mml:mn>4</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">P</mml:mi></mml:mrow><mml:mrow><mml:mn>12</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="

Sekine, Chihiro; Uchiumi, Takanori; Shirotani, Ichimin; Matsuhira, Kazuyuki; Sakakibara, Toshiro; Goto, T.; Yagi, T.

doi:10.1103/physrevb.62.11581

Cited by 82 publications

(49 citation statements)

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“…The wide range of hybridization between the R ions and the TX 3 polyanions leads to the large variety of thermodynamic and transport behaviours. These materials can be synthesized by conventional means with rare earth elements R = La-Eu, Yb; the skutterudites with R = Y, Gd, and Tb are formed only under large pressures up to 50 kbar [6,7]. The absence of the compounds with heavier rare earths (with the exception of Yb) is due presumably to the inadequate bonding of the heavier (smaller) R 3+ ions to the neighbouring ions in the somewhat rigid cages in the TX 3 structure.…”

Section: Introductionmentioning

confidence: 99%

Investigation of ferromagnetic filled skutterudite compounds EuT₄Sb₁₂(T = Fe, Ru, Os)

Bauer

Ślebarski

Frederick

et al. 2004

J. Phys.: Condens. Matter

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The physical properties of single crystals of filled skutterudite compounds EuT 4 Sb 12 (T = Fe, Ru, Os) have been investigated by means of x-ray diffraction, electrical resistivity, specific heat, magnetization, and x-ray absorption spectroscopy measurements. The Eu-based materials crystallize in the LaFe 4 P 12 -type structure (space group I m3 appears to exhibit either canted ferromagnetic or ferrimagnetic order at T C = 88 K whereas EuRu 4 Sb 12 and EuOs 4 Sb 12 are ferromagnets with Curie temperatures of T C = 4 and 9 K, respectively. X-ray absorption near edge spectroscopy measurements reveal a nearly divalent Eu electronic configuration for EuT 4 Sb 12 (T = Fe, Ru, Os) with no significant change with T atom or temperature.

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Section: Introductionmentioning

confidence: 99%

Investigation of ferromagnetic filled skutterudite compounds EuT₄Sb₁₂(T = Fe, Ru, Os)

Bauer

Ślebarski

Frederick

et al. 2004

J. Phys.: Condens. Matter

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“…Compared to other filled skutterudites, which show similar M-I transitions, PrRu 4 P 12 is unique since it has neither a magnetic anomaly at T MI , as seen in TbRu 4 P 12 [7], GdRu 4 P 12 [7], NdFe 4 P 12 [3] and SmRu 4 P 12 [8], nor anti-quadrupolar ordering as observed in PrFe 4 P 12 [9]. On the other hand, a subtle lattice distortion has been detected by electron diffraction measurements, which indicates weak superlattice spots at (h, k, l)(h + k + l = odd) below T MI [10].…”

mentioning

confidence: 99%

Charge-density-wave ordering in the metal-insulator transition compoundPrRu4P12

et al. 2004

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X-ray and electron diffraction measurements on the metal-insulator (M-I) transition compound PrRu4P12 have revealed the emergence of a periodic ordering of charge density around the Pr atoms. It is found that the ordering is associated with the onset of a low temperature insulator phase. These conclusions are supported by the facts that the space group of the crystal structure transforms from Im3 to Pm3 below the M-I transition temperature and also that the temperature dependence of the superlattice peaks in the insulator phase follows the squared BCS function. The M-I transition could be originated from the perfect nesting of the Fermi surface and/or the instability of the f electrons.PACS numbers: 61.10.-i, 61.14. Lj, 71.30.+h, 75.30.Mb Filled skutterudite compounds RM 4 X 12 (R = rareearth, M = Fe, Ru or Os; X = P, As or Sb) have attracted a great deal of interest in view of the origin of their dramatically variable physical properties. For example, they show metal-insulator (M-I) transitions [1], superconductivity [2,3,4] and large thermoelectric performance [5] depending on the combination of elements. To seek out the origin of this anomalous behavior, one of the important factors that must be understood is the topology of the Fermi surface. According to de Haas-van Alphen measurements, the shape of the Fermi surface in LaFe 4 P 12 is nearly cubic [6]. This implies the presence of nesting instability with a wave vector of q = (1,0,0). It was, thus, conjectured that some of the exotic properties in filled skutterudites originate from the nesting of the Fermi surface. To confirm this hypothesis, an intensive effort has been put. However, no clear evidence of nesting-induced phenomena has been identified so far.The filled skutterudite compound PrRu 4 P 12 , which is a metal at room temperature, has attracted a lot of attention due to interest in the origin of the M-I transition at T MI = 60 K [1]. Compared to other filled skutterudites, which show similar M-I transitions, PrRu 4 P 12 is unique since it has neither a magnetic anomaly at T MI , as seen in TbRu 4 P 12 [7], GdRu 4 P 12 [7], NdFe 4 P 12 [3] and SmRu 4 P 12 [8], nor anti-quadrupolar ordering as observed in PrFe 4 P 12 [9]. On the other hand, a subtle lattice distortion has been detected by electron diffraction measurements, which indicates weak superlattice spots at (h, k, l)(h + k + l = odd) below T MI [10]. To clarify the mechanism of the M-I transition, including the possibility of Fermi surface nesting, the precise crystal structure of the low temperature phase of PrRu 4 P 12 must be identified. To this end, we have carried out crystal structure analysis using electron and x-ray diffraction techniques.Single crystals of PrRu 4 P 12 were grown by a Sn flux method, which is described in detail elsewhere [10]. For electron diffraction measurements, the as-grown crystals were thinned down to 50 µm by mechanical polishing and then ion milled using an argon ion-beam thinning apparatus. For x-ray diffraction measurements, on the other hand, the as-g...

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“…However, experimental results on magnetic susceptibility for TbRu 4 P 12 have suggested two successive magnetic transitions at 20K and 10K. 20 As long as we fix x=0.37, the present CEF calculation indicates the Γ 1 singlet ground state. To explain the discrepancy, for instance, we may consider the deviation from the ideal point-charge picture.…”

Section: Cef Schemes For Filled Skutteruditesmentioning

confidence: 98%

“…For the skutterudites including rare-earth ions other than La, Ce, and Pr, the ferromagnetic ground state has been frequently observed, for instance, in RFe 4 P 12 for R=Nd, Sm, Eu, Gd, Tb, Dy, and Ho. However, in some Sm-, Gd-, and Tb-based skutterudites such as SmOs 4 Sb 12 , 19 GdRu 4 P 12 , 20 and TbRu 4 P 12 , 20 antiferromagnetic ground states have been also found. It is another characteristic issue of filled skutterudites that the magnetic properties are changed depending on the number of f -electrons n per rare-earth ion.…”

Section: Introductionmentioning

confidence: 99%

Microscopic Approach to Magnetism and Superconductivity of f-Electron Systems with Filled Skutterudite Structure

Hotta

2005

J. Phys. Soc. Jpn.

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In order to gain a deep insight into f -electron properties of filled skutterudite compounds from a microscopic viewpoint, we investigate the multiorbital Anderson model including Coulomb interactions, spinorbit coupling, and crystalline electric field effect. First we examine the local f -electron state in detail in comparison with the results of LS and j-j coupling schemes. For each case of n=1∼13, where n is the number of f electrons per rare-earth ion, the model is analyzed by using the numerical renormalization group (NRG) method to evaluate magnetic susceptibility and entropy of f electron. In particular, for the f 2 -electron system corresponding to the Pr-based filled skutterudite, it is found that magnetic fluctuations significantly remain at low temperatures, even when the ground state is Γ1 singlet, if Γ (2) 4 triplet is the excited state with small excitation energy. In order to make further step to construct a simplified model which can be treated even in a periodic system, we also analyze the Anderson model constructed based on the j-j coupling scheme by using the NRG method. It is clearly observed that the magnetic properties are quite similar to those of the original Anderson model. Then, we construct an orbital degenerate Hubbard model based on the j-j coupling scheme to investigate the mechanism of superconductivity of filled skutterudites. In the 2-site model, we carefully evaluate the superconducting pair susceptibility for the case of n=2 and find that the susceptibility for off-site Cooper pair is clearly enhanced only in a transition region in which the singlet and triplet ground states are interchanged. We envision a scenario that unconventional superconductivity induced by magnetic fluctuations may occur in the f 2 -electron system with Γ1 ground state such as Pr-based filled skutterudite compounds.

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Magnetic properties of the filled skutterudite-type structure compoundsGdRu4P12and
Chihiro Sekine
¹
,
Takanori Uchiumi
²
,
Ichimin Shirotani
³

et al.

Cited by 82 publications

References 20 publications

Investigation of ferromagnetic filled skutterudite compounds EuT₄Sb₁₂(T = Fe, Ru, Os)

Investigation of ferromagnetic filled skutterudite compounds EuT₄Sb₁₂(T = Fe, Ru, Os)

Charge-density-wave ordering in the metal-insulator transition compoundPrRu4P12

Microscopic Approach to Magnetism and Superconductivity of f-Electron Systems with Filled Skutterudite Structure

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Magnetic properties of the filled skutterudite-type structure compoundsGdRu4P12andChihiro Sekine1, Takanori Uchiumi2, Ichimin Shirotani3 et al.

Cited by 82 publications

References 20 publications

Investigation of ferromagnetic filled skutterudite compounds EuT4Sb12(T = Fe, Ru, Os)

Investigation of ferromagnetic filled skutterudite compounds EuT4Sb12(T = Fe, Ru, Os)

Charge-density-wave ordering in the metal-insulator transition compoundPrRu4P12

Microscopic Approach to Magnetism and Superconductivity of f-Electron Systems with Filled Skutterudite Structure

Contact Info

Product

Resources

About

Magnetic properties of the filled skutterudite-type structure compoundsGdRu4P12and
Chihiro Sekine
¹
,
Takanori Uchiumi
²
,
Ichimin Shirotani
³

et al.

Investigation of ferromagnetic filled skutterudite compounds EuT₄Sb₁₂(T = Fe, Ru, Os)

Investigation of ferromagnetic filled skutterudite compounds EuT₄Sb₁₂(T = Fe, Ru, Os)