Ground state configurations in antiferromagnetic ultrathin films with dipolar anisotropy

► Dipolar energy in collinear antiferromagnetic ultrathin films is calculated. ► Numerical results are presented for distorted fcc [001] structures. ► The lowest energy of a system depends on how the tetragonal distortion is achieved. ► A striped phase with magnetization in the [112¯] direction is the ground state. ► In multidomain NiO and MnO films it is eightfold degenerate.