Specific Heat of Single Crystal<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow><mml:mi mathvariant="normal">M</mml:mi><mml:mi mathvariant="normal">g</mml:mi><mml:mi mathvariant="normal">B</mml:mi></mml:mrow><mml:mn>2</mml:mn></mml:msub></mml:math>: A Two-Band Superconductor with Two Different Anisotropies

Bouquet, F.; Wang, Y.; Sheikin, I.; Plackowski, T.; Junod, A.; Lee, S.; Tajima, S.

doi:10.1103/physrevlett.89.257001

Cited by 201 publications

(156 citation statements)

References 34 publications

Supporting

Mentioning

135

Contrasting

Order By: Relevance

“…We also observe that the fit of H c2 is basi-cally unchanged above 1 T, meaning that low fields suppress the superconductivity due to the light electron band restoring a "single band" superconducting state. This is the same effect observed more directly in MgB 2 with specific heat measurements under magnetic field : the smaller gap rapidly vanishes, leading to a finite density of states at the Fermi level under magnetic fields due to the π band 36 . This suppression of the light quasiparticle superconductivity would have here an effect on specific heat too small to be observed (contribution of the light quasiparticles to the specific heat of order 4% of the Sommerfeld coefficient, itself buried in the large Schottky anomaly).…”

Section: Discussionsupporting

confidence: 78%

Superconducting phase diagram of the filled skuterruditePrOs4Sb12

et al. 2004

View full text Add to dashboard Cite

We present new measurements of the specific heat of the heavy fermion superconductor PrOs4Sb12, on a sample which exhibits two sharp distinct anomalies at Tc1 = 1.89K and Tc2 = 1.72K. They are used to draw a precise magnetic field-temperature superconducting phase diagram of PrOs4Sb12 down to 350 mK. We discuss the superconducting phase diagram of PrOs4Sb12 and its possible relation with an unconventional superconducting order parameter. We give a detailed analysis of Hc2(T ), which shows paramagnetic limitation (a support for even parity pairing) and multiband effects.

show abstract

Section: Discussionsupporting

confidence: 78%

Superconducting phase diagram of the filled skuterruditePrOs4Sb12

et al. 2004

View full text Add to dashboard Cite

show abstract

“…3]. These exercises suggest that the difference in the gap value of each band in this system is less substantial than the case of MgB 2 [28,29,30].…”

Section: Resultsmentioning

confidence: 78%

“…In particular, the two-gap superconductivity in MgB 2 manifests itself in the unusual temperature dependence of the anisotropy of H c1 in the superconducting state [28,29,30]. However, the reliable measurement of the lower critical field is a difficult task, in particular when strong vortex pinning is present as in the case of Fe-arsenides.…”

Section: Introductionmentioning

confidence: 99%

Penetration depth, lower critical fields, and quasiparticle conductivity in Fe-arsenide superconductors

Shibauchi

Hashimoto

Okazaki

et al. 2009

Physica C: Superconductivity

View full text Add to dashboard Cite

In this article, we review our recent studies of microwave penetration depth, lower critical fields, and quasiparticle conductivity in the superconducting state of Fe-arsenide superconductors. Highsensitivity microwave surface impedance measurements of the in-plane penetration depth λ ab in single crystals of electron-doped PrFeAsO1−y (y ∼ 0.1) and hole-doped Ba1−xKxFe2As2 (x ≈ 0.55) are presented. In clean crystals of Ba1−xKxFe2As2, as well as in PrFeAsO1−y crystals, the penetration depth shows flat temperature dependence at low temperatures, indicating that the superconducting gap opens all over the Fermi surface. The temperature dependence of superfluid density λ 2 ab (0)/λ 2 ab (T ) in both systems is most consistent with the existence of two different gaps. In Ba1−xKxFe2As2, we find that the superfluid density is sensitive to degrees of disorder inherent in the crystals, implying unconventional impurity effect. We also determine the lower critical field Hc1 in PrFeAsO1−y by using an array of micro-Hall probes. The temperature dependence of Hc1 saturates at low temperatures, fully consistent with the superfluid density determined by microwave measurements. The anisotropy of Hc1 has a weak temperature dependence with smaller values than the anisotropy of upper critical fields at low temperatures, which further supports the multi-gap superconductivity in Fe-arsenide systems. The quasiparticle conductivity shows an enhancement in the superconducting state, which suggests the reduction of quasiparticle scattering rate due to the gap formation below Tc. From these results, we discuss the structure of the superconducting gap in these Fe-arsenides, in comparison with the high-Tc cuprate superconductors.

show abstract

“…The curvature predicted for an isotropic gap 28 seems to be significant only at higher fields. However, for MgB 2 there is a relatively sharp bend in γ v (H) vs H that is associated with different values of H c2 for the two bands 31 , and perhaps an effect of that kind, but with a smaller difference in the values of H c2 , could be at work here.…”

Section: Discussionmentioning

confidence: 78%

Specific Heat of Ba_0.59K_0.41Fe₂As₂, an Fe-Pnictide Superconductor with T_c = 36.9 K, and a New Method for Identifying the Electron Contribution

et al. 2015

View full text Add to dashboard Cite

We report measurements of the specific heat of Ba 0.59 K 0.41 Fe 2 As 2 , an Fe-pnictide superconductor with T c = 36.9 K, for which there are suggestions of an unusual electron pairing mechanism. We use a new method of analysis of the data to derive the parameters characteristic of the electron contribution. It is based on comparisons of α-model expressions for the electron contribution with the total specific heat, which give the electron contribution directly. It obviates the need in the conventional analyses for an independent, necessarily approximate, determination of the lattice contribution, which is subtracted from the total specific heat to obtain the electron contribution. It eliminates the uncertainties and errors in the electron contribution that follow from the approximations in the determination of the lattice contribution. Our values of the parameters characteristic of the electron contribution differ significantly from those obtained in conventional analyses of specific-heat data for five similar holedoped BaFe 2 As 2 superconductors, which also differ significantly among themselves. For Ba 0.59 K 0.41 Fe 2 As 2 the electron density of states is comprised of contributions from two electron bands with superconducting-state energy gaps that differ by a factor 3.8, with 77% coming from the band with the larger gap. The variation of the specific heat with magnetic field is consistent with extended s-wave pairing, one of the theoretical predictions. The relation between the densities of states and the energy gaps in the two bands is not consistent with a theoretical model based on interband interactions alone. Comparison of the normal-state density of states with band-structure calculations shows an extraordinarily large effective mass 2 enhancement, for which there is no precedent in similar materials and no theoretical explanation.

show abstract

Specific Heat of Single CrystalMgB2: A Two-Band Superconductor with Two Different Anisotropies

Cited by 201 publications

References 34 publications

Superconducting phase diagram of the filled skuterruditePrOs4Sb12

Superconducting phase diagram of the filled skuterruditePrOs4Sb12

Penetration depth, lower critical fields, and quasiparticle conductivity in Fe-arsenide superconductors

Specific Heat of Ba_0.59K_0.41Fe₂As₂, an Fe-Pnictide Superconductor with T_c = 36.9 K, and a New Method for Identifying the Electron Contribution

Contact Info

Product

Resources

About

Specific Heat of Single CrystalMgB2: A Two-Band Superconductor with Two Different Anisotropies

Cited by 201 publications

References 34 publications

Superconducting phase diagram of the filled skuterruditePrOs4Sb12

Superconducting phase diagram of the filled skuterruditePrOs4Sb12

Penetration depth, lower critical fields, and quasiparticle conductivity in Fe-arsenide superconductors

Specific Heat of Ba0.59K0.41Fe2As2, an Fe-Pnictide Superconductor with Tc = 36.9 K, and a New Method for Identifying the Electron Contribution

Contact Info

Product

Resources

About

Specific Heat of Ba_0.59K_0.41Fe₂As₂, an Fe-Pnictide Superconductor with T_c = 36.9 K, and a New Method for Identifying the Electron Contribution