A Random Bond Ising Model Applied to the Magnetic Properties of FexMn0.6—xAl0.4 Disordered Alloys

Abstract

An Ising Hamiltonian, which includes diluted and random bonds, and the Mean Field Renormalization Group (MFRG) technique were used to obtain a theoretical phase diagram as a function of the antiferromagnetic sites concentration for the FexMn0.6—xAl0.4 system. A probability distribution was proposed in order to simulate the diluted and random bonds of the system. The competitive parameters and the exchange constants were fitted in such way that the calculated magnetic phase diagram was in excellent agreement with the experimental phase diagram obtained by magnetic susceptibility for the FexMn0.6—xAl0.4 alloy system. This model as well as the experimental results, propose several magnetic phases: antiferromagnetic, spin‐glass, reentrant spin‐glass, ferromagnetic and paramagnetic.