Ferromagnetism and chemical ordering in cobalt-iron

A short-range order dependent electronically self-consistent theory of ordering in ferromagnetic substitutional binary alloys is presented. The alloy internal energy is calculated using the cluster-Bathe-lattice method. The calculations use the results of elemental electronic structure calculations and experimental magnetic moments as input. The configuration dependence of the enthalpy of formation is used to determine the zero-temperature stable phases. Using this method it is found that ferromagnetism induces the A2 to B2 chemical ordering transition in the cobalt-iron system.