Computational study of magnetic properties of L10 ordered FeNi and FePt binary alloys

•The critical temperature of FeNi and FePt alloys using Heisenberg interaction is closer to the experimental value than the Ising interaction.•The FeNi and FePt alloys prefer a ferromagnetic phase over the ferrimagnatic phase.•The Ising interaction predicts higher critical temperature for the FeNi alloy than the Heisenberg interaction.•The Heisenberg interaction predicts higher critical temperature for the FePt alloy than the Ising interaction.