LOCAL-FIELD DISTRIBUTION OF THE VORTEX LATTICE NEAR-THE-SURFACE OF TYPE-II SUPERCONDUCTORS - MAGNETIC-RESONANCE LINESHAPES

The magnetic-field distribution of the flux-line lattice near the surf ace of a superconducting thin film is calculated. The field distributi on extends only about d/2 pi outside the superconductor, where d is th e intervortex distance, If a spin label of finite thickness is deposit ed onto the superconductor, its lineshape depends strongly on the pene tration depth, label thickness and intrinsic lineshape. The ideal thic kness of the surface label ammounts to approximate to d/2 pi. It is sh own that a surface ESR experiment is suitable for the determination of the penetration depth lambda in the reversible regime of high-T-c sup erconductors. In YBa2Cu3O7-delta the obtained slope d lambda(-2)/dT = -1.8 mu m(-2) K-1 just below T-c results in the Ginsburg-Landau parame ter kappa approximate to 56.