  Here, it is suggested that a four-point interaction of the tensor type may
lead to spin polarization in quark matter at high density. It is found that the
two-flavor superconducting phase and the spin polarized phase correspond to
distinct local minima of a certain generalized thermodynamical potential. It
follows that the transition from one to the other phase occurs passing through
true minima with both a spin polarization and a color superconducting gap. It
is shown that the quark spin polarized phase is realized at rather high
density, while the two-flavor color superconducting phase is realized at a
lower density region.
