Magnetization of the Site-Diluted Spin 1/2 Ising Model with Interactions in a Body Centered Cubic Lattice

In this work, we study the magnetic properties of the bcc lattice via site-diluted Ising model, using the operator differential technique by employing effective field theory. The results obtained here were applied to the study of the magnetic properties of Fe-Al alloys. We propose that only ferromagnetic interaction among nearest-neighbors Fe-Fe and the dependence of the exchange parameter with the aluminum concentration is quadratic. The results for the spontaneous magnetization coincides very well with the experimental data. The critical temperature as a function of aluminum concentration qualitatively describes the experimental phase diagram. We obtain the exchange interaction which is very close to that obtained using the Bogoulibov inequality and renormalization group technique.