Frequency dependence of the surface impedance of mixed-state type-II superconductors
Berezin V. A., Il'ichev E. V., Tulin V. A.
The frequency dependence of the real part of the surface impedance R (ω) of type-II superconductors with a small bulk pinning has been studied experimentally in an external magnetic field Hcl < Η < Hc2 in a perpendicular geometry. The change in the functional dependence R (ω) as a result of increasing the number of defects at the surface of a mixed-state superconductor has been observed for the first time. Experimental results have shown that this change is linked with the dynamics of the vortex lattice. The results obtained experimentally are qualitatively compared with the existing theoretical models.