  We investigate antiferromagnetic order of repulsively interacting fermionic
atoms in an optical lattice by means of Dynamical Mean-Field Theory (DMFT).
Special attention is paid to the case of an imbalanced mixture. We take into
account the presence of an underlying harmonic trap, both in a local density
approximation and by performing full Real-Space DMFT calculations. We consider
the case that the particle density in the trap center is at half filling,
leading to an antiferromagnetic region in the center, surrounded by a Fermi
liquid region at the edge. In the case of an imbalanced mixture, the
antiferromagnetism is directed perpendicular to the ferromagnetic polarization
and canted. We pay special attention to the boundary structure between the
antiferromagnetic and the Fermi liquid phase. For the moderately strong
interactions considered here, no Stoner instability toward a ferromagnetic
phase is found. Phase separation is only observed for strong imbalance and
sufficiently large repulsion.
