The effect of sub-lattice order in binary alloys with one magnetic component. II

Abstract

A first-order statistical approximation is used to investigate the relationship between ordering and magnetism in an alloy with one magnetic component. The theory includes the effects of short-range component and spin orderings, and is applicable to lattice structures which can be divided into two equivalent and completely interpenetrating sub-lattices. Using the Heisenberg model for the magnetic interaction and including first-nearest-neighbour interactions phase diagrams are obtained and presented in figs. 3–5 for various values of the parameters. These parameters are the exchange integral J, the spin s of the magnetic component and γ, which determines the relative strength of the non-magnetic interactions between atoms. The results are presented for negative values of γ because only then are conditions favourable for the development of component sub-lattice ordering. Comparison is made with the experimental data on the body-centred cubic phases of the ironaluminium system.