Superconducting nano-layer coating without insulator
  The superconducting nano-layer coating without insulator layer is studied. The magnetic-field distribution and the forces acting on a vortex are derived. Using the derived forces, the vortex-penetration field and the lower critical magnetic field can be discussed. The vortex-penetration field is identical with the multilayer coating, but the lower critical magnetic field is not. Forces acting on a vortex from the boundary of two superconductors play an important role in evaluations of the free energy. 
Takayuki Kubo
physics.acc-ph cond-mat.supr-con