The temperature dependence of intergranular and intragranular currents in (Bi,Pb)2Sr2Ca2Cu3O10+x superconductors was studied in low magnetic fields. In order to distinguish the two kinds of currents, the experiments were performed with two samples of similar grains: a bulk sample of well-coupled grains, and a sample without intergranular coupling (powder sample). The temperature dependence of intragranular currents exhibited a behaviour typical for S-N-S (superconductor-normal metal-superconductor) junctions. For intergranular currents the temperature dependence suggested a limitation due to thermally activated flux creep in the space between the superconducting grains.
- Critical current density
- Granular superconductivity