Contribution a l'etude experimentale de la supraconductivite de surface

In high magnetic fields, some materials are superconducting only in a superficial sheath of thickness ξ_T (typically 1000 Å), where ξ_T is the coherence length at temperature T. Theoretical prediction of this effect has been given by Saint-James and de Gennes.⁽¹⁾ Experiments on thin films are used to show the existence of this sheath, to study how its properties vary as a function of the applied magnetic field, and to measure directly its thickness. The influence of the proximity of a normal metal on surface properties of the superconducting film has also been studied.