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

Abstract

Binary alloys with one magnetic component and forming lattices divisible into four equivalent sub-lattices are discussed. The zeroth-order statistical approximation is used to derive the relation between sub-lattice order and magnetization for body-centred and face-centred cubic lattices. As a preliminary the types of order obtainable on four sub-lattices of the body-centred cubic lattice without magnetization are analysed. The interaction energies of both non-magnetic and ferromagnetic exchange types are taken to be of arbitrary range and the spin quantum number of the magnetic component is given an arbitrary value. Strong interaction with effects dependent on the energy parameters is observed between magnetization and component ordering; in particular the latter sometimes suppresses the former over considerable composition ranges. Typical phase diagrams are presented, showing the connection between Curie temperature curves and ordering transition temperature curves for sub-lattice order of 1:1 and 2:1:1 types in the body-centred cubic lattice and of 1:1 and 3:1 types in the face-centred cubic lattice.