Inhomogeneous magnetic flux distribution in Ag/Bi2223 tapes

The self magnetic field when applying transport current and the residual magnetic flux density after removing the external field were measured by means of scanning Hall probe technique and converted to the local current density distribution. The transport current density as well as the shield current density became highest at the edge part of the oxide core in Ag sheathed Bi2223 tape, which are larger than the transport critical current density measured by four terminal method. Inhomogeneity of magnetic field distribution along the current flow direction was attributed to the positional change of oxide layer thickness. The degree of inhomogeneity decreased for the tape with the higher transport critical current density.