  Spin polarization induced by an external electric field in graphene is
considered theoretically in the linear response regime. The graphene is assumed
to be deposited on a substrate which leads to the spin-orbit interaction of
Rashba type. The induced spin polarization is shown to be in the graphene plane
and perpendicular to the electric field. However, the spin polarization changes
sign when the Fermi level, whose position can be controlled by an external gate
voltage, crosses the Dirac points.
