We have determined the resistive upper critical field Hc2 for single crystals of the superconductor Fe1.11Te0.6Se 0.4 using pulsed magnetic fields of up to 60 T. A rather high zero-temperature upper critical field of μ0 Hc2 (0) 47 T is obtained in spite of the relatively low superconducting transition temperature (Tc 14K). Moreover, Hc2 follows an unusual temperature dependence, becoming almost independent of the magnetic field orientation as the temperature T→0. We suggest that the isotropic superconductivity in Fe 1.11Te0.6Se0.4 is a consequence of its three-dimensional Fermi-surface topology. An analogous result was obtained for (Ba,K) Fe2 As2, indicating that all layered iron-based superconductors exhibit generic behavior that is significantly different from that of the "high- Tc " cuprates.
|Original language||English (US)|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - Jan 27 2010|
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics