A8.4 Type 1 and Type 2 Superconductors
The difference between these types is in their behaviour in a magnetic field
Type 1: When an increasing applied magnetic field is applied to the conductor, it reaches a point when the Meissner effect suddenly breaks down and so it suddenly loses its superconductivity. Most pure metal superconductors are Type 1.
Type 2. Up to a certain temperature and at a particular field strength, these have normal superconductivity. Then, rather than this property suddenly disappearing at higher field strengths, some superconductivity remains, in other words the applied magnetic field penetrates the metal to some extent. The transition to being non-superconducting is more gradual but it does eventually stop at an upper critical temperature. Most alloys and ceramic superconductors are Type 2.