Coherent potential approximation for partially ordered alloys

An extension of the CPA technique is presented to account for the long-range order of atoms and/or antiferromagnetic solutions for simple cubic or body centred cubic crystallographic structures. Numerical calculations indicate that the influence of the ordering of atoms on the density of states is small for Fe_1-xNi_x alloys. The electronic energy shows that the non-ordered state is favourable. For Cr in antiferromagnetic state is obtained with energy close to the energy of the paramagnetic state. For Cr_0.5Fe_0.5 alloy the minimum of the free energy corresponds to the fully ordered state, which is a non-magnetic one.