The ground state of an impure FCC Ising antiferromagnet

It is shown that the almost pure FCC Ising antiferromagnet in its ground state has the same layered antiferromagnetic order as the pure FCC antiferromagnet. It is argued that this ground state persists until the concentration of magnetic sites falls to about 0.4. For concentrations between 0.18 and 0.4 the ground state is a spin glass.