The temperature and magnetic field dependence of superconducting critical current densities of multifilamentary Nb3Sn and NbTi composite wires

Commercial NbTi and Nb
3
Sn multifilamentary superconducting wire is becoming increasing important for use in research and commercial magnet systems. In both materials the temperature dependence of J
c
plays a major role in the determination of magnet system operating parameters and design stability margins. We report here critical current density measurements as a function of temperature from 4.2 to 19 K and of applied magnetic field upto 8 T for multifilamentary Nb
3
Sn wire and for 2 alloys of NbTi superconducting wire. From this data [
\partial J_{c}(H_{a})/\partialT
] and
[\partialH_{c2}/\partialT]T=T_{c}
can be obtained and stability criteria and other superconducting parameters of the wires may be extracted.