Y. Kohama

Pseudoisotropic Upper Critical Field in Cobalt-Doped SrFe2As2 Epitaxial Films

We present resistivity measurements of the complete superconducting upper critical field (H{c2}) phase diagram as a function of angle (theta) and temperature (T) for cobalt-doped SrFe2As2 epitaxial films to 0.5 K and 50 T. Although H{c2}(theta) at 10 K is indistinguishable from that derived from a single-band anisotropy model, the apparent anisotropy H{c2}{ perpendicularc}/H{c2};{ parallelc} linearly decreases to 1 at low T, with H{c2}(0)=47 T. The data are well described by a two-band model with small, opposing anisotropies for the bands. This unusual relationship is confirmed by the observation of a local maximum for H{c2};{ parallelc} at low T.

Weak anisotropy of the superconducting upper critical field in Fe 1.11 Te 0.6 Se 0.4 single crystals

We have determined the resistive upper critical field Hc2 for single crystals of the superconductor Fe1.11Te0.6Se0.4 using pulsed magnetic fields of up to 60T. A rather high zero-temperature upper critical field of mu0Hc2(0) approx 47T is obtained, in spite of the relatively low superconducting transition temperature (Tc approx 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 Fe1.11Te0.6Se0.4 is a consequence of its three-dimensional Fermi-surface topology. An analogous result was obtained for (Ba,K)Fe2As2, indicating that all layered iron-based superconductors exhibit generic behavior that is significantly different from that of the high-Tc cuprates.

Upper critical field and thermally activated flux flow in single-crystalline Tl 0 . 58 Rb 0 . 42 Fe 1 . 72 Se 2

The upper critical field

Thermal Transport and Strong Mass Renormalization in NiCl(2)-4SC(NH(2))(2)

\mu_0H_{c2}(T_c)

Doping dependence of the upper critical field and Hall resistivity of LaFeAsO1-x Fx (x=0, 0.025, 0.05, 0.07, 0.11, and 0.14)

of Tl

Asymmetric Quintuplet Condensation in the Frustrated S ¼ 1 Spin Dimer Compound Ba3Mn2O8

_{0.58}

Hall coefficient and Hc2 in underdoped LaFeAsO0.95F0.05

Rb

Hall coefficient and H

_{0.42}

_{c2}

Fe

in underdoped LaFeAsO

_{1.72}