Strong-coupling effects on κ2 (T) for high-Tc superconductors

The authors study strong-coupling effects on the slope of the magnetization curve at Hc2, parametrized by the generalized Ginzburg-Landau parameter κ. Anisotropy effects are taken into account. The use of the quasiclassical equations allows the authors to present the calculations as well as the results in a particularly transparent manner. In the isotropic, weak-coupling limit, Eilenberger's results are reproduced (apart from a minor correction). Special emphasis is given to high-temperature superconductors. It turns out that the slope of κ(T) at Tc is a very sensitive probe for strong-coupling and anisotropy effects. This observation may be useful in the discussion of whether or not low-lying excitations contribute to be attractive mechanism in high-Tc oxide superconductors