Low temperature specific heats of H(NbIrO) and R(NbPtO)

Cort, B.; Giorgi, A.L.; Stewart, G. R.

doi:10.1007/bf00682027

Cited by 18 publications

(17 citation statements)

References 16 publications

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“…3(a)). T c 's of Nb 5 Ir 3 O and Nb 5 Pt 3 O are approximately 10.1 K and 4.3 K, respectively, which are in agreement with the literature values [5,6]. As x is increased, T c does not shift for the sample with x ≤ 0.6 and starts to decrease at x ≥ 0.6.…”

Section: Resultssupporting

confidence: 90%

“…We note that the deviation from the linearity is commonly observed in the Ti 5 Ga 4 -type superconductors [8,14] such as Zr 5 Pt 3 O x and Nb 5 Ge 3 C 0.3 . [6]. Therefore, the electronic density of states at the Fermi level would partially determine T c .…”

Section: Resultsmentioning

confidence: 99%

“…The temperature dependence of specific heat of Nb 5 Ir 3 O cannot be reproduced by a single exponential temperature dependence, but explained by a two-gap model [5]. The bulk superconductivity with T c of 3.8 K has been confirmed for Nb 5 Pt 3 O by measuring the specific heat, which seems to follow a single exponential temperature dependence just below T c but shows the deviation at low temperature [6]. In this study, Pt-substitution effect on T c is investigated in the solid solution system Nb 5 Ir 3−x Pt x O to further elucidate the superconductivity of Ti 5 Ga 4 -type compounds.…”

Section: Introductionmentioning

confidence: 94%

“…Although physical properties of many Ti 5 Ga 4 -type compounds are studied [1][2][3][4], the superconductivity is reported only in several compounds [5][6][7][8][9] [5] with the critical temperature T c = 9.3 K, and by increasing the oxygen concentration, T c progressively increases to 10.5 K. In this case, the oxygen addition leads to the shrinkage of c and the expansion of a, which is regarded as the enhancement of one-dimensionality of Nb2 6 and Nb1 atomic chains. The temperature dependence of specific heat of Nb 5 Ir 3 O cannot be reproduced by a single exponential temperature dependence, but explained by a two-gap model [5].…”

Section: Introductionmentioning

confidence: 99%

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Superconductivity in Nb₅Ir₃₋_xPt_xO

Kitagawa

Hamamoto

2020

Proceedings of the International Conference on Strongly Correlated Electron Systems (SCES2019)

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We have investigated the superconducting critical temperature T c of solid solution Nb 5 Ir 3−x Pt x O with the Ti 5 Ga 4-type structure. The both end-members of Nb 5 Ir 3 O and Nb 5 Pt 3 O are reported to be superconductors with T c of 10.5 K and 3.8 K, respectively. Particularly Nb 5 Ir 3 O is considered as a two-gap superconductor. The entire series of alloy hold the Ti 5 Ga 4-type structure and show the linear x dependence of lattice parameters. On the other hand, a nonlinear T c vs x plot was obtained, suggesting that T c is not determined by only lattice parameters. The experimental result is discussed based on the Matthias rule and compared with those of the other two-gap superconductors such as MgB 2 , Mo 8 Ga 41 and Nb 3 Sn.

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Section: Resultssupporting

confidence: 90%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Superconductivity in Nb₅Ir₃₋_xPt_xO

Kitagawa

Hamamoto

2020

Proceedings of the International Conference on Strongly Correlated Electron Systems (SCES2019)

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“…The lower critical field µ 0 H c1 is related to the magnetic penetration depth λ and the coherence length ξ via µ 0 H c1 = (Φ 0 /4πλ 2 )[ln(κ) + 0.5], where κ = λ/ξ is the GL parameter 13 . By using µ 0 H c1 = 11.5 (2) The zero-field specific heat data in the low-T region ( Fig. 6) show a sharp jump at T c again indicating a bulk superconducting transition and a good sample quality.…”

Section: Methodsmentioning

confidence: 99%

Crossover from multiple- to single-gap superconductivity in Nb5Ir3−xPtxO alloys

Jöhr

Das

et al. 2020

Phys. Rev. B

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By using mostly the muon-spin rotation/relaxation (µSR) technique, we investigate the superconductivity (SC) of Nb 5 Ir 3−x Pt x O (x = 0 and 1.6) alloys, with T c = 10.5 K and 9.1 K, respectively. At a macroscopic level, their superconductivity was studied by electrical resistivity, magnetization, and specific-heat measurements. In both compounds, the electronic specific heat and the low-temperature superfluid density data suggest a nodeless SC. The superconducting gap value and the specific heat discontinuity at T c are larger than that expected from the Bardeen-Cooper-Schrieffer theory in the weak-coupling regime, indicating strongcoupling superconductivity in the Nb 5 Ir 3−x Pt x O family. In Nb 5 Ir 3 O, multigap SC is evidenced by the field dependence of the electronic specific heat coefficient and the superconducting Gaussian relaxation rate, as well as by the temperature dependence of the upper critical field. Pt substitution suppresses one of the gaps, and Nb 5 Ir 1.4 Pt 1.6 O becomes a single-gap superconductor. By combining our extensive experimental results, we provide evidence for a multiple-to single-gap SC crossover in the Nb 5 Ir 3−x Pt x O family.

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