COLLECTIVE OSCILLATIONS IN SUPERCONDUCTING THIN FILMS IN THE PRESENCE OF VORTICES

A plasma wave propagates inside an anisotropic superconducting film sandwiched between two semi-infinite non-conducting bounding dieletric media. Along the c-axis, perpendicular to the film surfaces, an external magnetic field is applied. We show how vortices, known to cause dissipation and change the penetration depth, affect the propagative mode. We obtain the complex wave number of this mode and, using YBCO at 4 K as an example, determine a region where vortex contribution is dominant and dissipation is small.