A new theoretical approach to the Fe1−qAlq in the bcc lattice by employing effective field theory

► We propose a new theoretical approach to the FeAl in the bcc lattice by employing effective field theory. ► Here one suggests a new approach to exchange interaction between nearest neighbors of Fe that depends on the powers of the Al (q). ► We clarified the dependence of the Al concentration with critical temperature. ► This approach differs from earlier works in literature and leads to a good agreement with the experimental data. ► Our approach does not require the introduction of superexchange interaction.