Hello Aspirant,

I hope you ae doing well.

An ideal superconductor screens the B-field completely at B-fields lower than the critical field.

This makes a superconductor perfectly diamagnetic and thus the magnetic susceptibility (X) is equal to -1. Superconductors take the diamagnetic effect to the extreme, since in a superconductor the field B is zero – the field is completely screened from the interior of the material. Thus the relative permeability of a superconductor is zero.