AC LOSSES OF SUPERCONDUCTING HIGH-T-C MULTIFILAMENT BI-2223 AG SHEATHED TAPES IN PERPENDICULAR MAGNETIC-FIELDS

We have measured at 4.2 K and partly also at 77 K the hysteresis and coupling losses of three different superconducting c-axis oriented Bi-2223/Ag multifilament tapes. The inter- and intragranular contributions to the hysteresis losses were analyzed and their dependence on dB/dt was investigated. The penetration field of a very flat filament was calculated. We could separate the measured coupling losses from the also dB/dt dependent hysteresis losses. Further we calculated the geometry dependence of the coupling losses of a very flat multifilament tape. The measured coupling losses can be described by a general scaling law with a generalized frequency wt. A skin-effect-like behavior has been found for omega tau > 1 and AC loss saturation occurs for large AC field amplitudes.