The temperature and magnetic field dependence of superconducting critical current densities of multifilamentary Nb<inf>3</inf>Sn and NbTi composite wires

Abstract

Commercial NbTi and Nb <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> Sn multifilamentary superconducting wire is becoming increasing important for use in research and commercial magnet systems. In both materials the temperature dependence of J <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</inf> 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 <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> Sn wire and for 2 alloys of NbTi superconducting wire. From this data [ <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">\partial J_{c}(H_{a})/\partialT</tex> ] and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">[\partialH_{c2}/\partialT]T=T_{c}</tex> can be obtained and stability criteria and other superconducting parameters of the wires may be extracted.