Abstract
The self-field distributions caused by the trapped currents were measured on the surfaces of the Ag-sheathed (Bi, Pb)2Sr2Ca2Cu3Ox monofilamentary tapes using a scanning Hall sensor with an active area 50 μm× 50 μm, after the applied magnetic fields perpendicular to the sample surface were turned off. The samples were fabricated by a powder-in-tube method combining the cold rolling process with an intermediate sintering step. The measured field profiles were nearly symmetric, and explained by the intergranular current transport that flowed through grain boundaries. The weak links induced by cold rolling on the tape caused a change in the field distributions, and the results were ascribed to the intragranular currents restricted within the grains themselves. In the tape after cold rolling, there existed macro-cracks along the width direction that are likely to disturb the current flow along the length direction. The experimental behavior was qualitatively explained by numerical calculations on the assumption of simplified current paths using the Biot-Savart law.
