Some superconducting properties of 25%Nb–75%Zr alloy

The manner of preparation of superconducting 25% wt Nb–75% wt Zr wires is described. Short samples of these wires were measured in static magnetic fields up to 80·5 kG and the authors describe the method of these measurements. The paper gives the results of measuring the critical current density dependence on the external perpendicular magnetic field for both cold-worked wires with different deformations and heat-treated wires. The dependence of the critical current density on the heat treatment temperature after wire deformation for different magnetic fields was obtained. The optimum heat treatment temperature (vacuum better than 10^–3 torr, 1 hour) is 450–600C for magnetic fields 0–80·5 kG. The values ofi_c of these wires in magnetic fields up to 60 kG are the same or higher than those of 75% Nb-25% Zr wires, and in fields above 60 kG they are much higher.