SURFACE SUPERCONDUCTIVITY OF SHORT COHERENCE LENGTH SUPERCONDUCTORS

Abstract

Based on the theory of Valls et al. for short coherence length superconductors, de Gennes' boundary theory for conventional superconductors with xi(0)>>k(F)(-1) may be modified. We solve the G-L equation exactly under zero magnetic field for various temperatures. The order parameter psi(x) is not depleted but enhanced near the surface. We also obtain some interesting results: T-c will be enhanced by contracting of the thickness of a superconducting film. The nucleation field H-c3(T) proportional to (T-cb-T) near T-cb; and H-c3(T)proportional to(T-c-T)(1/2) near T-c. The critical current in SIS Josephson junctions J(c)(T)proportional to(T-c- T) + root 2 tau(0)(T-0-T) for T<T-cb; and J(c)(T)proportional to(T-c-T) for T(cb)less than or equal to T<T-c.