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 nonconducting bounding dielectric media. In the presence of a c-axis-parallel magnetic field, perpendicularly applied to the film surfaces, 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 YBa2Cu3O7-x at 4 K as an example, determine a region where the vortex contribution is dominant and dissipation is small.