Transport properties in valence fluctuation compound Sm3Se4

Tamaki, Akira; Gotô, Terutaka; Sugita, Mitsuharu; Kunii, S.; Suzuki, Takao; Fujimura, Tadao; Kasuya, T.

doi:10.1016/0304-8853(83)90288-3

Cited by 6 publications

(3 citation statements)

References 2 publications

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“…The quasielastic signal observed in the magnetic spectral response of Sm 3 Te 4 (figure 5) can be ascribed to spin fluctuations occurring within the degenerate ground state of the Sm 3+ ions. The spin-fluctuation time estimated from the experimental half-width /2 is in the order of 10 −12 s, orders of magnitude shorter than the value, τ = 10 −7 s at T = 100 K, derived from the 77 Se NMR in Sm 3 Se 4 [3]. However, these two values are not contradictory because the spin-fluctuation time corresponds to the relaxation of individual spins within the Sm 3+ configuration, which can be much faster, especially at low temperature, than the valence-fluctuation time associated with the exchange of 2+ and 3+ states.…”

Section: Discussionmentioning

confidence: 67%

“…Unlike most other Th 3 P 4 -type rare-earth chalcogenides (cubic I 43d space group), which are trivalent and metallic [1], the Sm 3 X 4 (X = S, Se, Te) compounds behave as semiconductors, with a room-temperature electrical resistivity already of the order of 1 cm, and an activation energy, deduced from ρ(T ), of 0.12-0.14 eV (Sm 3 S 4 [2], Sm 3 Se 4 [3]). This situation reflects the peculiar electronic band structure of these materials, in which the 4f level is located at the Fermi energy, inside the band gap (E g ≈ 4 eV for Sm 3 S 4 [2]), but close to the bottom of the 5d-6s conduction band.…”

Section: Introductionmentioning

confidence: 99%

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Neutron scattering study of the magnetic excitation spectra in mixed-valence¹⁵⁴Sm₃Te₄

Alekseev

Mignot

Kahn

et al. 2000

J. Phys.: Condens. Matter

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The magnetic properties of the unconventional mixed-valence compound Sm3 Te4 have been studied by inelastic neutron scattering. Time-of-flight experiments with different incident energies (Ei = 300 meV, 67 meV and 3.2 meV) and energy resolutions have been performed on isotopic (low-absorption) 154 Sm3 Te4 and on the reference compound La3 Te4 . Spectral contributions from two coexisting valence states Sm2+ and Sm3+ were clearly identified. In contrast to previous results for SmB6 , the spectra can be analysed in terms of well defined 4f 5 and 4f 6 local moments subjected to the crystal field. However, the data reveal that di- and trivalent ions, which occupy identical crystallographic sites, feel quite different crystal-field potentials. Quasielastic scattering was found to exist down to the minimum temperature (1.5 K) of the measurements, with a half-width of about 0.45 meV. This implies that spin fluctuations, with a much higher fluctuation rate than the valence fluctuations reported in a recent NMR study, exist just above the spin-glass transition.

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Section: Discussionmentioning

confidence: 67%

Section: Introductionmentioning

confidence: 99%

Neutron scattering study of the magnetic excitation spectra in mixed-valence¹⁵⁴Sm₃Te₄

Alekseev

Mignot

Kahn

et al. 2000

J. Phys.: Condens. Matter

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show abstract

“…Unlike most other Th 3 P 4 -type rare-earth chalcogenides, which are trivalent and metallic [364], the Sm 3 X 4 compounds behave as semiconductors, with a room-temperature electrical resistivity already of the order of 1 Ωcm. The activation-type temperature dependence of the dc resistivity ρ = ρ 0 exp(E/k B T) has a unique value of the activation energy E ≈ 0.14 eV for Sm 3 X 4 (X = S, Se, or Te) [315,438]. The optical measurements reveal a direct energy gap in Sm 3 S 4 and Eu 3 S 4 equal to 0.2 eV and 1.7 eV, respectively [439,440].…”

Section: Sm and Eu Pnictides And Chalcogenidesmentioning

confidence: 97%

Electronic Structure of Strongly Correlated Systems

Antonov

Bekenov

Yaresko

2011

Advances in Condensed Matter Physics

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The article reviews the rich phenomena of metal-insulator transitions, anomalous metalicity, taking as examples iron and titanium oxides. The diverse phenomena include strong spin and orbital fluctuations, incoherence of charge dynamics, and phase transitions under control of key parameters such as band filling, bandwidth, and dimensionality. Another important phenomena presented in the article is a valence fluctuation which occur often in rare-earth compounds. We consider some Ce, Sm, Eu, Tm, and Yb compounds such as Ce, Sm and Tm monochalcogenides, Sm and Yb borides, mixed-valent and charge-ordered Sm, Eu and Yb pnictides and chalcogenides R4X3and R3X4(R = Sm, Eu, Yb; X = As, Sb, Bi), intermediate-valence YbInCu4and heavy-fermion compounds YbMCu4(M = Cu, Ag, Au, Pd). Issues addressed include the nature of the electronic ground states, the metal-insulator transition, the electronic and magnetic structures. The discussion includes key experiments, such as optical and magneto-optical spectroscopic measurements, x-ray photoemission and x-ray absorption, bremsstrahlung isochromat spectroscopy measurements as well as x-ray magnetic circular dichroism.

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Rare Earth Elements and Selenium

Bergmann¹,

Hein²,

Kühn³

et al. 1985

Sc, Y, La-Lu Rare Earth Elements C 9

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Transport properties in valence fluctuation compound Sm3Se4

Cited by 6 publications

References 2 publications

Neutron scattering study of the magnetic excitation spectra in mixed-valence¹⁵⁴Sm₃Te₄

Neutron scattering study of the magnetic excitation spectra in mixed-valence¹⁵⁴Sm₃Te₄

Electronic Structure of Strongly Correlated Systems

Rare Earth Elements and Selenium

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Transport properties in valence fluctuation compound Sm3Se4

Cited by 6 publications

References 2 publications

Neutron scattering study of the magnetic excitation spectra in mixed-valence154Sm3Te4

Neutron scattering study of the magnetic excitation spectra in mixed-valence154Sm3Te4

Electronic Structure of Strongly Correlated Systems

Rare Earth Elements and Selenium

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Neutron scattering study of the magnetic excitation spectra in mixed-valence¹⁵⁴Sm₃Te₄

Neutron scattering study of the magnetic excitation spectra in mixed-valence¹⁵⁴Sm₃Te₄