Analysis of Coupling Losses in Multifilamentary Untwisted BSCCO/Ag Tapes Through a.c. Susceptibility Measurements

Losses as a function of the a.c. magnetic field amplitude have been evaluated at 77 K in untwisted BSCCO(2223)/Ag tapes, at different frequencies, by measuring the imaginary part of a.c. magnetic susceptibility. In particular, the measurements were performed on different portions of the same tape, obtained by cutting it in pieces with different length, starting from around 120~mm down to 10~mm. The experimental results show that the losses depend on the sample length, but this observed behavior can not be always ascribed to the coupling mechanism among filaments. In this work we discuss the observed experimental behavior for different typologies of tapes. The data are analyzed by comparing them with the results obtained by means of analytical models allowing us to characterize the tapes with respect to the coupling mechanisms.