Discovered to be superconducting in 1954 by B. T. Matthias, T. H. Geballe, S. Geller, and E. Corenzwit, and shown in 1961 by J. E. Kunzler and co-workers to sustain over 100,000 A/cm² at 8.8 T.
Because the A15 intermetallic phase is mechanically brittle and strain-sensitive, composite wires of ductile Nb and Cu-Sn precursors are wound into magnet coils first and then heat-treated ('wind-and-react') to form Nb3Sn.
Remaining superconducting up to 30 T with Tc = 18.3 K, roughly 600 metric tons of Nb3Sn strands form the 13.5 T central solenoid and 11.8 T toroidal field coils of the ITER fusion reactor as well as high-luminosity LHC quadrupoles.