Position and amplitude of proximity effect peaks in the magnetization curves of NbTi/Cu and NbTi/CuMn multifilamentary strands

This paper reports on the magnitude and position of proximity-effect-related magnetization peaks in the M-H loops of multifilimentary NbTi superconductive composites that have been studied. M-H loops were taken at T = 4.2 K as a function of field-sweep amplitude, HM, for several specimens. Three regimes emerge: low field, where proximity effects are mainly shielding in nature; high field, where there are anomalous trapping effects; an intermediate field region, corresponding to a crossover between these two regimes. Correlations are made between these regimes and the specimen parameters HCl,NbTi and Hp,NbTi. A relationship is found between the magnitude of the maximum of the high field magnetization (MEX) and the breakdown field of the copper (Hbr)