New model of the pinning potential barrier in HTc superconductors
  New model of the pinning potential barrier in multi-layered HTc superconductors has been presented, basing on geometrical approach to the capturing interaction of pancake type vortices with nano-scale defects. Using this model the transport current flow phenomena in these materials, especially current-voltage characteristics and critical current density, have been considered. Details of theoretical analysis are given, including derivation of basic mathematical equations describing the potential barrier in the function of transport current density and initial position of captured pancake vortex. Computer simulation has been performed then of influence of transport current amplitude on potential barrier height for various sizes of pinning centers and initial pancake vortex position as well as influence of fast neutrons irradiation on critical current of HTc layered superconductor. 
J. Sosnowski
cond-mat.supr-con