Evidences for intermediate valence behavior in CeNi5In

Rojas, D.P.; Pereira, Laura C. J.; Salamakha, P.; Lopes, Elsa B.; Waerenborgh, J.C.; Silva, L.M. da; Gandra, F. G.

doi:10.1016/j.jallcom.2004.08.052

Cited by 5 publications

(3 citation statements)

References 8 publications

(20 reference statements)

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“…very low value of susceptibility and its weak temperature dependence down to 100 K clearly indicate that Ce ions are in valence fluctuating state. Similar shape of susceptibility curves has been observed and are typical for Ce-based valence fluctuating compounds [24,25,26,27]. Sometimes the magnetic susceptibility does show a curie tail at lower temperatures in valence fluctuating systems for instance in Ce 2 Co 3 Ge 5 ,[24] Ce 2 Ni 3 Si 5 ,[27] and CeNi 2 B 2 C [28].…”

supporting

confidence: 78%

Valence Fluctuation in CeMo2Si2C

Paramanik,

Burkhard,

Prasad

et al. 2013

Preprint

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We report on the valence fluctuation of Ce in CeMo 2 Si 2 C as studied by means of magnetic susceptibility χ(T ), specific heat C(T ), electrical resistivity ρ(T ) and x-ray absorption spectroscopy. Powder x-ray diffraction revealed that CeMo 2 Si 2 C crystallizes in CeCr 2 Si 2 C-type layered tetragonal crystal structure (space group P4/mmm). The unit cell volume of CeMo 2 Si 2 C deviates from the expected lanthanide contraction, indicating non-trivalent state of Ce ions in this compound. The observed weak temperature dependence of the magnetic susceptibility and its low value indicate that Ce ions are in valence fluctuating state. The formal L III Ce valence in CeMo 2 Si 2 C < ν> = 3.11 as determined from x-ray absorption spectroscopy measurement is well bellow the value < ν>≃ 3.4 in tetravalent Ce compound CeO 2 . The temperature dependence of specific heat does not show any anomaly down to 1.8 K which rules out any magnetic ordering in the system. The Sommerfeld coefficient obtained from the specific heat data is γ = 23.4 mJ/mol K 2 . The electrical resistivity follows the T 2 behavior in the low temperature range below 35 K confirming a Fermi liquid behavior. Accordingly both the Kadowaki Wood ratio A/γ 2 and the Sommerfeld Wilson ratio χ(0)/γ are in the range expected for Fermi-liquid systems. In order to get some information on the electronic states, we calculated the band structure within the density functional theory, eventhough this approach is not able to treat 4f electrons accurately. The non-f electron states crossing the Fermi level have mostly Mo 4d character. They provide the states with which the 4f sates are strongly hybridized, leading to the intermediate valent state.

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supporting

confidence: 78%

Valence Fluctuation in CeMo2Si2C

Paramanik,

Burkhard,

Prasad

et al. 2013

Preprint

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“…However, the values are still smaller than µ µ = 7.94 eff B /Eu for a stable divalent Eu 2+ ion. The shapes of the magnetic susceptibilities of EuNi 2 (P 1−x Ge x ) 2 with ⩽ ⩽ x 0 0.4 (figure 3) are typical of those for valence-fluctuating Ce compounds [14][15][16][17][18], where sometimes the magnetic susceptibility shows a Curie tail at lower temperatures [17,19], which arises due to the presence of a magnetic impurity.…”

Section: Magnetizationmentioning

confidence: 87%

Valence fluctuation and magnetic ordering in EuNi₂(P_1−xGe_x)₂single crystals

Paramanik

Bar²,

Das

et al. 2016

J. Phys.: Condens. Matter

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Unusual phases and phase transitions are seen at the magnetic-nonmagnetic boundary in Ce, Eu and Yb-based compounds. EuNi2P2 is a very unusual valence fluctuating Eu system, because at low temperatures the Eu valence stays close to 2.5 instead of approaching an integer value. Eu valence and thus the magnetic property in this system can be tuned by Ge substitution in P site as EuNi2Ge2 is known to exhibit antiferromagnetc (AFM) ordering of divalent Eu moments with TN = 30 K. We have grown EuNi2(P1−xGex)2 (0.0 ≤ x ≤ 0.5) single crystals and studied their magnetic, thermodynamic and transport properties. Increasing Ge doping to x > 0.4 results in a well-defined AFM ordered state with TN = 12 K for x = 0.5. Moreover, the reduced value of magnetic entropy for x = 0.5 at TN suggests the presence of valance fluctuation/ Kondo effect in this compound. Interestingly, the specific heat exhibits an enhanced Sommerfeld coefficient upon Ge doping. Subsequently, electronic structure calculations lead to a non-integral valence in EuNi2P2 but a stable divalent Eu state in EuNi2Ge2 which is in good agreement with experimental results.

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“…Our results indicate that the values of bulk modulus, Debye temperature and static equilibrium volume depend on the method of calculations, although the dierences are small. We have also shown that the DebyeGrüneisen model gives the dependence of the specic heat versus temperature for CeNi 5 Sn similar to CeNi 5 In [6].…”

Section: Discussionmentioning

confidence: 52%

Electronic Structure and Thermodynamic Properties of RNi₅Sn (R = La, Ce, Pr, Nd) Compounds

2015

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The electronic structure, pressure and temperature dependence of thermodynamic properties of RNi5Sn (R = La, Ce, Pr, Nd) compounds are calculated by ab initio full potential local orbital minimum-base(ver. 9 and ver. 14) method. These compounds crystallize in the hexagonal crystal structure (space group P 6c/mmc, No. 194). The band calculations were performed in the scalar-relativistic mode for the exchange correlation potentials in the form of the PerdewBurkeErnzerhof general gradient approximation. In this work we present the band structures of LaNi5Sn, CeNi5Sn, NdNi5Sn and PrNi5Sn compounds. The thermodynamic properties (bulk modulus, Debye temperature) are calculated in the DebyeGrüneisen model using the equation of states in the form of BirchMurnaghan, PoirierTarantola and Vinet. Our results have shown that values of thermodynamic properties depend on the method of calculations.

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Evidences for intermediate valence behavior in CeNi5In

Cited by 5 publications

References 8 publications

Valence Fluctuation in CeMo2Si2C

Valence Fluctuation in CeMo2Si2C

Valence fluctuation and magnetic ordering in EuNi₂(P_1−xGe_x)₂single crystals

Electronic Structure and Thermodynamic Properties of RNi₅Sn (R = La, Ce, Pr, Nd) Compounds

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Evidences for intermediate valence behavior in CeNi5In

Cited by 5 publications

References 8 publications

Valence Fluctuation in CeMo2Si2C

Valence Fluctuation in CeMo2Si2C

Valence fluctuation and magnetic ordering in EuNi2(P1−xGex)2single crystals

Electronic Structure and Thermodynamic Properties of RNi5Sn (R = La, Ce, Pr, Nd) Compounds

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Valence fluctuation and magnetic ordering in EuNi₂(P_1−xGe_x)₂single crystals

Electronic Structure and Thermodynamic Properties of RNi₅Sn (R = La, Ce, Pr, Nd) Compounds