The electron spin density fluctuation theory is developed for disordered alloys. The model contains two types of magnetic atoms characterized by different intra-atomic exchange interactions because ...of their different nearest neighborhood. The microscopic approach allow us to describe the various temperature behaviors of the magnetization of the Fe-Al alloys (25 - 32 at.% Al) observed in experiments. Competition parallel and antiparallel orientations of subsystems Fe(1) and Fe(2) gives rise to a diverse and anomalous temperature behavior of magnetism in partially and strongly disordered alloys.
We propose a theory for the quantitative description of the thermodynamic, magnetic and electronic properties of disordered alloys of transition metals and normal, for example, the system Fe-Al, as ...obtained from melting, and in the form of metastable states produced by mechanical grinding. System of itinerant d-electrons with two constants of the intra-atomic exchange interaction is investigated by the fluctuating field approach. Fundamentally new feature of the system is the presence of several ferrimagnetic solutions, transitions between which give variety to the temperature dependence of the magnetic characteristics of disordered alloys. Results of calculation of the temperature dependences of the magnetic characteristics of iron aluminum alloys are considered as an application of the theory.
