On the Phase Diagram of Spin-Polarized Attractive Hubbard Model: Weak   Coupling Limit
  The superfluid properties of the attractive Hubbard model in a Zeeman magnetic field, and in the weak coupling regime have been investigated. The temperature and magnetic field dependencies of the order parameter have been analyzed. Furthermore, the temperature vs. magnetic field and temperature vs. spin polarization phase diagrams for the 2D and 3D lattices have been obtained. For some parameters a reentrant transition has been found. 
Agnieszka Kujawa, Roman Micnas