The numbers that matter
Critical field
The magnetic field a superconductor tolerates before it gives up. Most things people want superconductors for are magnets, so the material has to survive its own field.
Why critical field matters
A magnet's own field is the load its conductor has to tolerate, so critical field is read at the operating temperature rather than on its own.
Where critical field comes up
Critical field in a real conductor
- NbTiA ductile niobium-titanium alloy, and the only superconductor that can be drawn into wire on machinery a copper mill would recognize.
- Nb₃SnA brittle intermetallic with roughly twice the transition temperature of NbTi, and a manufacturing process built entirely around the fact that it cannot be bent.
- MgB₂Magnesium diboride: two cheap, light, abundant elements that turned out in 2001 to superconduct far warmer than any other simple compound.
Related to critical field
SuperMatics is a platform infrastructure company for superconducting devices: software that finds the material and the process, lab work that makes and measures it, and pilot manufacturing with industrial partners.If you have a device and a constraint it has to meet, tell us about it.