Using density functional theory, we study the magnetic stability of the
Ga1−xMnxN alloy system. We show that unlike Ga1−xMnxAs, which
shows only ferromagnetic (FM) phase, Ga1−xMnxN can be stable in either
FM or antiferromagnetic phases depending on the alloy concentration. The
magnetic order can also be altered by applying pressure or with charge
compensation. A unified model is used to explain these behaviors.Comment: 4 pages, 4 figure