Aren’t the LHC magnets niobium-titanium? Those aren’t high temperature superconductors. Though it is indeed a metal under any definition. The rule of thumb is that high-temperature superconductors can be cooled by liquid nitrogen alone. This is not the case of the LHC magnets, which also have a liquid helium cooling loop.
> They're metallic, so you can form them into the shape you need without having to manufacture it in that shape to begin with, since you'd need another superconductor to join pieces like glue, which we don't have.
The term “metallic” is unhelpful because often in material science it just means an electronic conductor (a material with a non-zero density of states at the Fermi level). Under that definition, some ceramics are metallic, and the opposite of “metallic” is “insulator”, or sometimes “semi-conductor”.
YBCO, which is probably the most used high-temperature superconductor, is an oxyde, so a ceramic, but still an electronic (super)conductor, so metallic. The fact that it’s an oxyde does not prevent its use, notably in spherical tokamaks.
So I don’t know the person you’re referencing but their background work on the subject seems less than adequate, from what you say.
They're saying that LHC does not use a ceramic, and therefore high-temperature, superconductor; instead they use metallic (cooled) superconductors because they can be molded.
https://www.pca.state.mn.us/pollutants-and-contaminants/poly...