Upper critical field of borocarbide superconductors

Abstract

We have investigated the upper critical fields of Y1-xErxNi2B2C and Y1-xErxPd5B3C0.4 (0 less than or equal to x less than or equal to 1) systems by the scaling analysis of the thermal fluctuation conductivity, The experiments were done over wide magnetic field range. We are going to test the thermal fluctuation theory in the borocarbide superconducting systems. According to the scaling analysis, the thermal fluctuation conductivity should be scaled as sigma (f) = (T-2/H)(1/3) F[AT-T-c(H)/(TH)(2/3)]. Because the scaling function is field independent, all scaling curves obtained under various applied fields should converge to a universal curve if the function of T,(H) is properly chosen. We therefore obtain H-c2(T) determined by optimizing the scaling fit, The superconducting coherence length and Ginzburg-Landau parameter kappa in those superconductors are also estimated. We categorize the Y1-xErxNi2B2C and Y1-xErxPd5B3C0.4 systems as strong type-II superconductors

Strongly Correlated Superconductivity inRh17S15

“…5 is a good fit to the formula, H C2 T H C2 0 1 ÿ T=Tc 3=2 3=2 where T C is the transition temperature at zero field. The estimated value of H C2 0 is 23.5 T and the value of T C is 5.4 K. This temperature dependence of the upper critical field is a characteristic feature of charged bosons in the narrowband system [10,11]. For charged bosons, a large value of H C2 0 is expected and one expects a -type anomaly in the heat capacity at T C which is not seen here (Fig.…”

“…3 shows nearly a mean-field -like superconducting transition). However, such a fit has been used to explain the temperature dependence of the upper critical field of oxides (Ba 1ÿx K x BiO 3 ) as well of intermetallic superconductors such as borocarbides [10,11]. The experimental results suggest that the narrow 4d band electrons play an important role in the superconducting pairing mechanism in Rh 17 S 15 .…”

Characterization of the heavy metal pyrochlore lattice superconductor CaIr2

“…The WHH expression and the empirical formula are widely used to calculate the µ 0 H c2 (0) for a variety of intermetallic and oxide superconductors. 3,[21][22][23] The upper critical field value µ 0 H c2 (0) can be used to estimate the Ginzburg-Landau coherence length ξ(0) = Φ 0 /2πH c2 (0) = 99 Å, where Φ 0 = hc 2e is the magnetic flux quantum. 25,26 This value is higher than that of the Laves phase CeRu 2 (see Table .…”

Superconductivity in the Topological Nodal-line Semimetal NaAlSi

“…The previously proposed formula for a superconductivity with a local electron pairing, Hc2(T) = Hc2(0)[1 − (T/Tc) 3/2 ) 3/2 , 25) has been successfully applied to many superconductors including PbTaSe2 14) and borocarbides. 26) We used this formula to fit the whole Hc2(T) data sets and obtained excellent fits with μ0Hc2(0) = 7.93(6) and 1.50(3) T for H || a and c, respectively. The former value is smaller than the Pauli limiting field of 1.84Tc = 12.4 T, and the latter value is close to the reported Hc2(0) value of 1.91T for a polycrystalline sample.…”