The Effect of Doping with Al on the Stability of D03 and L12 Phases in Fe73.44(Ga,Al)26.56 Alloys: Ab Initio Calculation and Monte Carlo Modeling.

The effect of doping with Al on the stability of D0₃ and L1₂ phases was studied in the magnetostriction Fe–Ga and Fe–Ga–Al alloys with a high content of nonmagnetic atoms of ≈27 at %. For the studied D0₃ and L1₂ structures, the tetragonal shear modules C' = (C₁₁ – C₁₂)/2 and the Debye temperatures Θ_D were found by the methods of density functional theory. The replacement of 4.58 at % of Ga by Al atoms was shown to lead to an increase in Θ_D and a decrease in C′. Using the combined approach ab initio and Monte Carlo modeling, the calculations of free energies were performed, and the D0₃–L1₂ phase transition temperatures were determined. The Al addition to the Fe–Ga system was shown to decrease the difference between the energies of the D0₃ and L1₂ structures. [ABSTRACT FROM AUTHOR]