I'm no patent lawyer, but there is literally a US patent-office category covering "material" for exactly this kind of invention. Section 505 - "Superconductor Technology: Apparatus, Material, Process".
> This is the generic class for subject matter involving (a) superconductor technology above 30 K and (b) Art collections involving superconductor technology. Apparatus, devices, materials, and processes involving such technology are included herein.
https://www.uspto.gov/web/patents/classification/uspc505/def...