Spin dynamics and the Pauli exclusion principle

[atomiclaser]

TL;DR Summary

How does pauli exclusion principle affect the superconductivity?

For high temperature superconductivity, people usually say two quasifree electrons are pairing, one is spin up and the other one is spin down.
So, if that is the case, each two electrons will have zero spin angular momentum. Since the superconductivity is the magnetic properties and spin is the microessens of magnet, so if electrons are pairing, there should be no magnetic and how superconductivity works?

 

[anuttarasammyak]

No magnetic field permeates into super conductor (of the first kind) . It seems harmonious to the fact as you mentioned that Couper pair has zero spin.