  By means of first principles calculations we demonstrate an effective method
to tailor the local spin configuration of graphene on Co(0001) surface through
nitrogen doping. Two different site occupancies of the N impurities are
discussed with the focus on structural, electronic and magnetic properties. N
induces opposite local spin polarization at the two sites through Zener
exchange-type hybridization with Co substrate. In addition, the induced spin
polarization is energy dependent and controllable by electric field.
Consequently this structure can be applied as a spin injection source in
graphene based spintronics.
