MAGNETIC SCREENING IN PROXIMITY-COUPLED SUPERCONDUCTOR NORMAL-METAL BILAYERS

The electrodynamics of a metallic surface layer in proximity contact t o a superconductor are considered. The surface region is modeled as an idealized proximity-coupled superconductor/normal-metal (S/N) bilayer . Analytical expressions for the magnetic-field penetration into the s ample are obtained. The behavior of the model and its applicability to magnetic-screening-length measurements on artificial and naturally oc curring S/N bilayer supeconductors are discussed in various limits. Ca lculations of the effective penetration depth lambda(eff)(T) reveal th at unconventional penetration depth temperature dependences, such as D elta lambda(eff)(T)similar to T found in YBa2Cu3O7-delta crystals, are qualitatively reproduced with this model.