New measurements of critical data of optimized NBTi superconductors

The critical data jcand Bc2of NbTi based alloy s.c. material (Ti contents between 39 and 52 wt %) have been determined in the range from 4.2 to 1.8 K. In the case of optimized pinning structure the results are in good accordance with the function Bc2(T) = Bc2(O)(1-t²). The current density can be described by the scaling law Fp=c.Bc2^3.5b(1-b). The stabilisation parameter To(as a function of B and T) is derived from the experimental data. Technical aspects concerning the application of s.c. material are discussed.