Ag-sheath magnetoresistance anisotropy in Bi(2223)/Ag multifilamentary tapes at 4.2 K
Abstract:The magnetoresistance of three different pure Ag, respectively BSCCO/Ag, tapes was examined. Further, the voltage-current characteristics of two 19-filament Bi(2223)/Ag short samples differing by current carrying capability were measured at 4.2 K in magnetic fields up to 10 T. The voltage-current characteristics were used to evaluate the differential resistance in the resistive regime as a function of current. The saturated value of the differential resistance was determined by extrapolation to relatively high currents and it was considered as the apparent silver sheath resistance. It showed a very low value in spite of various technological steps during preparation. It agreed well with the calculated value using the resistivity of the long-time heat treated pure Ag sample. The magnetic field-induced increase in resistance calculated in this way was lower than that, or approximately equal to that, measured in the transverse position with the broad face parallel with the magnetic field and/or in the longitudinal position. In contrast, in the transverse position with the broad face perpendicular to the magnetic field, the magnetoresistance was higher than the calculated one. The observed anisotropy ratio of the apparent silver sheath magnetoresistance was close to 2. Some mechanisms that could be responsible for such behaviour are discussed.
Document Type: Miscellaneous
Publication date: July 1, 1998