By its very nature (normal) superconductivity (condensation of electrons into the BCS ground state) cannot exist together with ferromagnetism (condensation of electrons into the same spin state, all pointing in the same direction).
Reentrance is when while changing a continuous parameter, superconductivity is first observed, then destroyed by the ferromagnetic order, and later reappears.
When cooling, first superconducting order appears in the electron system.
At even lower energy superconductivity reenters, and a nonuniform magnetic order appears.
there is ferromagnetic order on short length scales, but superconducting order on large length scales.