Electronic and magnetic structure of the ternary fcc Mn-Fe-Ni system. II. Disordered alloys and ferromagnetic-antiferromagnetic interfaces

Abstract

We have developed a novel statistical theory of fcc ternary Mn-Fe-Ni alloys based on a decomposition of the fcc lattice into space-filling atomic tetrahedra whose magnetic properties are estimated from the magnetic properties of analogous tetrahedra in ordered fcc ternary compounds. Using this theory, we have calculated the average total moment and root-mean-square moment per atom as a function of alloy composition and lattice constant. As an application of this statistical theory, we discuss the magnetic properties of the permalloy MnFe-alloy interface, which is an example of a two-dimensional disordered fcc ternary Mn-Fe-Ni alloy. Because of the hybrid nature of the atomic environment at this interface, there is a ferrimagnetic transition layer between ferromagnetic permalloy and antiferromagnetic MnFe regions. This feature has been largely ignored in discussions of this structure but should be taken into account in treating the magnetic properties of this interface. © 1990 The American Physical Society.