Type I and Type II Superconductors
Type I and Type II Superconductors: exhibit different magnetic response to external magnetic field.
In Type I superconductor the magnetic field iscompletely expelled from the interior for B<BC.
Type II superconductors have two values of critical magnetic field, for B<BC1 the magnetic field is completely expelled (Type-I behavior), whereas for BC1<B<BC2 the magnetic field partially penetrates through the material.
The bulk of superconductor material breaks down into two regions: superconductive from which the external field is completely expelled, and normal through which the external field penetrates.
The normal regions are distributed as filaments filled with the external magnetic field. The flux of magnetic field through the filaments is quantized. Electric current is induced at the interface between the normal and the superconductive regions, the “surface” of filaments is “wrapped” in current which cancels the magnetic field in the superconductive regions.
The electric current is carried by the superconductive regions of Type-II material.