Theory of Electromagnetic Properties of Strong-Coupling and Impure Superconductors. II

The effects of strong coupling and of spin-flip scattering by magnetic impurities on the electromagnetic properties of superconductors are discussed. We have found that the surface resistance ($\frac{R_s}{R_N}$) of lead, a strong-coupling superconductor, reflects the phonon spectrum and has characteristic peaks (∼1.02) near frequencies ∼8×${10}^{-3\mathrm{}}$ and 11×${10}^{-3\mathrm{}}$ eV, and has a small dip (∼0.95) near frequency ∼22×${10}^{-3\mathrm{}}$ eV. Extensive calculations of the conductivity and surface impedance for superconductors containing magnetic impurities at finite temperatures, especially in the gapless region, are described.