Microwave response, complex conductivity and effect of order parameter symmetry in Fe-based superconductors

Thus, microwave surface impedance measurements of Fe-pnictide superconductors allow accurate finding reactive and real part of complex conductivity of these materials despite of their small dimensions. At present, microwave measurements do not disturb consensus regarding the wave symmetry in all studied Fe-based superconductors. In turns, the complex conductivity makes it possible to find the temperature dependence of not only the penetration depth, but also quasiparticle conductivity and the rate of quasiparticle scattering. Here we obtain a chance to find the absolute value of the rate. Obviously, we will have a lot of work in this direction in a wide range of lengths of electromagnetic waves. In addition, the complex conductivity of the pnictides in temperature range above T_c is of undoubted interest too.