Magnetization decay effects in NbTi multifilamentary superconducting wires

The magnetization decay effect over time was studied for NbTi multifilamentary wires of various cross-sectional structures. It was found that the lower the electrical resistivity between filaments and the smaller the spacing between filaments of a specimen, the larger its magnetization decay rate. It was further found that the rate of magnetization decay was anisotropic with respect to the applied field, with rates being higher when the field was applied perpendicular to the wire axis. There was also a dependence of field profile, but results were complicated by supplemental magnetic flux. All these types of behavior were found to be attributable to the presence of a weakly superconductive portion induced by the proximity effect, and were explained by this model