Wen Hai-Hu

Nodal Gap in Fe-Based Layered Superconductor LaO0.9F0.1-δ FeAs Probed by Specific Heat Measurements

We report the specific heat measurements on the newly discovered Fe-based layered LaO0.9F0.1-δFeAs superconductor with the onset transition temperature Tc ≈ 28K. A nonlinear magnetic field dependence of the electronic specific heat coefficient γ(H) has been found in the low temperature limit, which is consistent with the prediction for a nodal superconductor. The maximum gap value Δ0 ≈ 3.4 ± 0.5 meV is derived by analysing γ(H) based on the d-wave model. We also detected the electronic specific heat difference between 9 T and 0 T in a wide temperature range, a specific heat anomaly can be clearly observed near Tc. The Debye temperature of our sample is determined to be about 315.7K. Our results suggest an unconventional mechanism for this new superconductor.

Strong Quantum Fluctuation of Vortices in Bulk Samples of the New Superconductor MgB2

By using transport and magnetic measurement, the upper critical field

Sizable Residual Quasiparticle Density of States Induced by Impurity Scattering Effect in Ba(Fe1−xCox)2As2 Single Crystals

H_{c2}(T)

Possible Superconductivity at 37 K in Graphite-Sulphur Composite

and the irreversibility line

Superconducting Properties of MgB2 Prepared by High Pressure and Ambient Pressure

H_{irr}(T)

Rapid preparation of Mg(B1-xCx)(2) superconductor using hybrid microwave method

has been determined. A big separation between

Preparation and Characterization of the New Superconductor MgB2

H_{c2}(0)

Specific heat of the non-centrosymmetric superconductor Re3W

and

Upper critical field and irreversibility line determined by transport measurement of the new superconductor MgB2

H_{irr}(0)

Weak quantum flux creep and strong pinning in the new superconductor MgB2

has been found showing the existence of a quantum vortex liquid state induced by quantum fluctuation of vortices in the new superconductor