What is the relevance of n‑value in superconductivity?

If you come to superconductivity from a general physics or engineering background, one concept tends to feel oddly under‑explained: the n‑value. It’s not part of the classic London equations. It doesn’t appear in BCS theory. And yet, if you talk to anyone designing superconducting magnets, power cables, or fusion devices, n‑value suddenly becomes critically important. […]
Fujikura and UK Industrial Fusion Solutions Limited (UKIFS) sign framework agreement for supply of high temperature superconductors

Fujikura has been selected as a supplier of high temperature superconductors for the Spherical Tokamak for Energy Production (STEP) programme