Magnetic flux distribution in polycrystalline Bi,Pb-Sr-Ca-Cu-O superconductors in a cyclic state

The authors have studied magnetic flux distribution in polycrystalline (Bi,Pb)/sub 2/Sr/sub 2/Ca/sub 2/Cu/sub 3/O/sub 10+x/ superconductors at 77 K at different stages of an external magnetic field cycle using a movable miniature Hall sensor. The measured magnetic field profiles are compared to profiles achieved by numerical field calculations. The existence of both inter- and intragranular currents causes deviations to the field profiles predicted by classical critical state models, leading to incorrect critical current density estimations, when using standard magnetization measurements.<
>