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

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 mH z at 77 K. Hall probe technique was used for magnetization measurements on tape as well as filament samples. A calibration method based on the propert ies of the virgin curve is described. We also measured resistivity between a filament and Ag matrix for an individual filaments extracted from the tap e. To detect filament intergrowths we measured I-V curves on tape sample wi th current flowing in the tape perpendicular to its axis. Consequences of t he observed effects for the interpretation of AC loss behavior of multifila mentary tapes are discussed. (C) 2001 Elsevier Science B.V. All rights rese rved.