Precursor for manufacturing Nb3Sn superconducting wire and Nb3Sn superconducting wire

A precursor for manufacturing a Nb3Sn superconducting wire by an internal Sn process, the precursor comprising:

• a multi-element wire having a center portion including a plurality of mono-element wires;
• each of said plurality of mono-element wires having a Cu or Cu-based alloy matrix into which an Sn or Sn-based alloy core is embedded, and having a plurality of Nb or Nb-based alloy filaments surrounding the Sn or Sn-based alloy core, said plurality of Nb or Nb-based alloy filaments configured to have an average distance from the outer diameter of the Sn or Sn-based alloy core of 100 μm or less;
• and at least one of said plurality of Nb or Nb-based alloy filaments configured to have a distance from the outer diameter of the Sn or Sn-based alloy core of 50 μm or less;
• and said plurality of Nb or Nb-based alloy filaments having an average diameter of 5 μm to 30 μm, and a diffusion barrier layer surrounding said plurality of Nb or Nb-based alloy filaments;
• and
• a stabilizing copper layer surrounding each of said mono-element wires.