Magneto-optical investigations as a tool to improve quality of (Pb,Bi)-2223 tapes

Flux distributions of multifilamentary (Pb,Bi)2223 tapes are investigated b y magneto-optic (MO) imaging at T = 10K and in different field orientations , This enables to study differences between the individual filaments in a d irect way. To our knowledge we have for the first time applied the field pe rpendicular to a cross section of an intact tape, i.e. the external field i s aligned along the individual filaments, This geometry of the MO experimen ts enables the study of the superconducting properties of the filaments as a function of position in the tape. The flux patterns reveal the shielding properties (= critical current density) of the filaments; and the studies c learly show differences in the superconducting properties between the diffe rent filaments. Our observations provide therefore important informations f or further development of the (Pb,Bi)-2223 tapes.