Study of important factors affecting AC losses of multifilamentary Bi-2223 tapes

We measured DC critical currents and magnetization curves on samples of Bi-2223/Ag multifilamentary tape with 55 untwisted filaments and on individual filaments extracted from the tape at frequencies from few mHz up to 150 mHz at 77 K. Hall probe technique was used for magnetization measurements on tape as well as filament samples. A calibration method based on the properties of the virgin curve is described. We also measured resistivity between a filament and Ag matrix for an individual filaments extracted from the tape. To detect filament intergrowths we measured I-V curves on tape sample with current flowing in the tape perpendicular to its axis. Consequences of the observed effects for the interpretation of AC loss behavior of multifilamentary tapes are discussed. (C) 2001 Elsevier Science B.V. All rights reserved.