INTERGRAIN FLUX-CREEP IN HIGH-T(C) SUPERCONDUCTORS

Equations describing the intergrain flux creep of ceramic superconduct ors are derived. They are based on the behavior of small superconducti ng loops closed by overdamped Josephson junctions. The elementary loop s are formed around nonsuperconducting regions between the grains, the loops acting as pinning centers. Despite different pinning mechanisms the equations for the relaxation of the intergrain current density in a static and a slowly varying external magnetic field are formally si milar to those of the classical flux-creep theory based on volume pinn ing.