Metal–Insulator Transition of Filled Skutterudite Compound SmRu<sub>4</sub>P<sub>12</sub>

Matsuhira, Kazuyuki; Hinatsu, Yukio; Sekine, Chihiro; Togashi, Tatsuya; Maki, Hiroyuki; Shirotani, Ichimin; Kitazawa, Hideaki; Takamasu, T.; Kido, G.

doi:10.1143/jpsjs.71s.237

Cited by 76 publications

(67 citation statements)

References 17 publications

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“…Magnetic measurements show that Sm is trivalent with total angular momentum J = 5/2. Specific heat measurements suggest a crystalline electric field (CEF) scheme consisting of a Γ 67 ground state quartet and an excited doublet Γ 5 at about 60 K in the T h symmetry [4,8]. This scheme is plausible for understanding other measurements including the elastic * Electronic address: yoshizawa@iwate-u.ac.jp constant [9,10].…”

Section: Introductionmentioning

confidence: 92%

“…The interest in SmRu 4 P 12 is due to its metal-insulator (MI) transition at T MI ∼ 16.5 K, a subsequent antiferromagnetic (AFM) transition at T N ∼ 14 K [3], and a strange H-T magnetic phase diagram [4,5]. T N is obscure at lower magnetic fields; however, it is distinctly visible in several measurements like thermal expansion [6] even in a zero magnetic field.…”

Section: Introductionmentioning

confidence: 99%

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Anomalous elastic softening ofSmRu4P12under high pressure

et al. 2007

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The filled skutterudite compound SmRu4P12 undergoes a complex evolution from a paramagnetic metal (phase I) to a probable multipolar ordering insulator (phase II) at TMI ∼ 16.5 K, then to a magnetically ordered phase (phase III) at TN ∼ 14 K. Elastic properties under hydrostatic pressures were investigated to study the nature of the ordering phases. We found that distinct elastic softening above TMI is induced by pressure, giving evidence of quadrupole degeneracy of the ground state in the crystalline electric field. It also suggests that quadrupole moment may be one of the order parameters below TMI under pressure. Strangely, the largest degree of softening is found in the transverse elastic constant CT at around 0.5-0.6 GPa, presumably having relevancy to the competing and very different Grüneisen parameters Ω of TMI and TN. Interplay between the two phase transitions is also verified by the rapid increase of TMI under pressure with a considerably large Ω of 9. Our results can be understood on the basis of the proposed octupole scenario for SmRu4P12.

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Section: Introductionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Anomalous elastic softening ofSmRu4P12under high pressure

et al. 2007

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“…Moreover, the Γ 8 CEF ground state has been reported in the Smbased filled skutterudite. 25 Thus, we expect to apply the present model to Sm-based filled skutterudites. When we compare our result on the bcc lattice with the experimental suggestion, octupole ordering actually occurs in our model for the bcc lattice, but Γ 2u octupole ordered state does not seem to explain the experimental results.…”

Section: B Bcc Latticementioning

confidence: 95%

“…21,22 It is noted that in these materials, crystalline electric field (CEF) ground states are Γ 8 quartets with large degeneracy even under a CEF potential. 23,24,25 In the Γ 8 ground-state multiplet, octupoles exist as independent moments besides dipole and quadrupole moments. 26 Then, phenomenological theories have been developed under the assumption that octupole ordering occurs.…”

Section: Introductionmentioning

confidence: 99%

Multipole ordering inf-electron systems on the basis of aj−jcoupling scheme

Kubo

Hotta

2005

Phys. Rev. B

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We investigate microscopic aspects of multipole ordering in f -electron systems with emphasis on the effect of lattice structure. For the purpose, first we construct f -electron models on three kinds of lattices, simple cubic (sc), bcc, and fcc, by including f -electron hopping through (f f σ) bonding in a tight-binding approximation on the basis of a j-j coupling scheme. Then, an effective model is derived in the strong-coupling limit for each lattice structure with the use of second-order perturbation theory with respect to (f f σ). By applying mean-field theory to such effective models, we find different types of multipole ordered state depending on the lattice structure. For the sc lattice, a Γ3g antiferro-quadrupole transition occurs at a finite temperature and as further lowering temperature, we find another transition to a ferromagnetic state. For the bcc lattice, a Γ2u antiferrooctupole ordering occurs first, and then, a ferromagnetic phase transition follows it. Finally, for the fcc lattice, we find a single phase transition to the longitudinal triple-q Γ5u octupole ordering.

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“…Sm based skutterudite is one of the most extensively studied filled skutterudites. Among them, SmT 4 P 12 (T = Fe, Ru, Os) system shows curious features such as the first Sm-based heavy fermion ferromagnet in SmFe 4 P 12 [5] or the new type of multi-polar ordered state in SmRu 4 P 12 [6,7]. SmOs 4 P 12 is one of them and is reported as a Kondo lattice antiferromagnet with T N ∼ 4.5 K. The antiferromagnetic transition is confirmed by magnetic susceptibility χ, electrical resistivity ρ, specific heat C and NMR measurements.…”

Section: Introductionmentioning

confidence: 99%

Magnetic and Transport Properties of Filled Skutterudite SmOs₄P₁₂under Pressure

et al. 2012

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Filled skutterudite SmOs 4 P 12 is reported as a Kondo lattice compound with antiferromagnetic order at T N ∼ 4.5 K. We have measured the electrical resistivity and the magnetization under pressure up to 1.4 GPa on SmOs 4 P 12 . We revealed the increase of T N by applying pressure at a rate of ∼ 0.4 K/GPa. This ratio is consistent with the value of 0.5 K/ GPa predicted by thermal expansion and specific heat measurements.

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Metal–Insulator Transition of Filled Skutterudite Compound SmRu₄P₁₂

Cited by 76 publications

References 17 publications

Anomalous elastic softening ofSmRu4P12under high pressure

Anomalous elastic softening ofSmRu4P12under high pressure

Multipole ordering inf-electron systems on the basis of aj−jcoupling scheme

Magnetic and Transport Properties of Filled Skutterudite SmOs₄P₁₂under Pressure

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Metal–Insulator Transition of Filled Skutterudite Compound SmRu4P12

Cited by 76 publications

References 17 publications

Anomalous elastic softening ofSmRu4P12under high pressure

Anomalous elastic softening ofSmRu4P12under high pressure

Multipole ordering inf-electron systems on the basis of aj−jcoupling scheme

Magnetic and Transport Properties of Filled Skutterudite SmOs4P12under Pressure

Contact Info

Product

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Metal–Insulator Transition of Filled Skutterudite Compound SmRu₄P₁₂

Magnetic and Transport Properties of Filled Skutterudite SmOs₄P₁₂under Pressure