Magnetic and resistive behaviour of a superconducting Nb-54 at% Ta cylinder

The magnetic and resistive behaviour of a superconducting Nb-54 at% Ta cylinder has been investigated by application of transport currents and axial magnetic fields. Three distinguishable magnetic states of the system have been identified. One which has not previously been reported, seems to arise as a result of the low normal state resistivity of the alloy. The viscous drag forces are important in an otherwise nearly force free system. The results are related to earlier measurements on lead-based alloys and resistance-only measurements on NbTa alloys; some unification of viewpoint emerges. (author)