We consider the effect of nonmagnetic and magnetic impurities on the superheating field H s in a type-II superconductor. We solved the Eilenberger equations, which take into account the nonlinear pairbreaking of Meissner screening currents, and calculated H s (T ) for arbitrary temperatures and impurity concentrations in a single-band s-wave superconductor with a large Ginzburg-Landau parameter. At low temperatures, nonmagnetic impurities suppress a weak maximum in H s (T ), which has been predicted for the clean limit, resulting, instead, in a maximum of H s as a function of impurity concentration in a moderately clean limit. It is shown that nonmagnetic impurities weakly affect H s even in the dirty limit, while magnetic impurities suppress both H s and the critical temperature T c . The density of quasiparticles states N ( ) is strongly affected by an interplay of impurity scattering and current pairbreaking. We show that a clean superconductor at H = H s is in a gapless state, but a quasiparticle gap g in N ( ) at H = H s appears as the concentration of nonmagnetic impurities increases. As the nonmagnetic scattering rate α increases above α c = 0.36, the quasiparticle gap g (α) at H = H s increases, approaching g ≈ 0.32 0 in the dirty limit α 1, where 0 is the superconducting gap parameter at zero field. The effects of impurities on H s can be essential for the nonlinear surface resistance and superconductivity breakdown by strong RF fields.

We formulate the time-dependent Ginzburg-Landau theory, with the assumption of local equilibrium made in the reference frame floating with normal electrons. This theory with floating nucleation kernel is applied to the far infrared conductivity in the Abrikosov vortex lattice. It yields better agreement with recent experimental data ͓Phys. Rev. B 79, 174525 ͑2009͔͒ than the customary time-dependent Ginzburg-Landau theory.

The comprehensive ρ(T) measurements and the consequent resistivity curvature mapping (RCM) on Y 0.7 Ca 0.3 Ba 2 Cu 3 O 7−δ thin films (doping levels p = 0.08-0.21) elucidate a phase diagram for the whole doping range. This phase diagram further strengthens a view that the 'normal' phase in hole-doped cuprates should be divided into a strong superconducting (SC) fluctuation phase and the 'real' normal phase in which there is no significant influence of SC. The temperature of superconducting fluctuations T f as a function of p was calculated using the Ginzburg-Landau model for layered superconductors. Comparisons between T f and the Nernst temperature establish the origin of the Nernst effect as SC fluctuations. Some of the details in ρ(T) cannot be fully understood by the existing models and call for a more sophisticated theory of carrier dynamics in cuprates.

Following Gor'kov and Éliashberg ͓Zh. Eksp. Teor. Fiz. 54, 612 ͑1968͔͒, we derive the time-dependent Ginzburg-Landau equation from the nonequilibrium Green functions. Space-gradient terms appearing due to anisotropic perturbations of quasiparticles are evaluated. It is shown that the dominant contribution due to the normal current can be included with no increase in the complexity of the set of equations.