Stability limit of the Meissner state in thin superconducting films

The local stability of Meissner states in thin superconducting films is determined by studying the effect of small fluctuations on solutions of the Ginzburg-Landau (GL) equations. As a function of the GL parameter κ, it is shown that the instability mode is uniform in the film plane for κ<~κ0 with κ0=1.13. The instability boundary also defines the region in which solutions of the GL equations exist. For κ>κ0, on the other hand, the instability mode is periodic in the film plane and there exist solutions of the GL equations which are not locally stable. The results are compared with those found by other workers for semi-infinite half-space superconductors.