In the present study, first-principles molecular dynamics simulations were employed to study the effects of small amounts of B and C substituted for P on the structure and magnetic properties of Fe₈₀P₁₃C₇, Fe₈₀P₁₀C₇B₃, and Fe₈₀P₈C₉B₃ amorphous alloys. A small amount of B and C replacing P atoms increases the icosahedral structure of the amorphous alloys, especially the increase in the regular icosahedral structure. The saturation magnetization of the three kinds of amorphous alloys gradually increases with the addition of B and C atoms, and the results of experimental and simulated calculations show consistent trends. The substitution of P atoms by B and C atoms leads to the aggregation of Fe atoms, which increases the magnetic moment of the iron atoms. In addition, the improvement of local structural symmetry may be one of the reasons for the increase in saturation magnetization of amorphous alloys. The substitution of a small number of B and C atoms plays an important role in improving the saturation magnetization of the amorphous alloy, which has a certain guiding significance for the development of amorphous alloys with excellent soft magnetic properties.

The effects of the substitution of Fe by Co or Ni on both the structure and the magnetic properties of FeB amorphous alloy were investigated using first-principle molecular dynamics. The pair distribution function, Voronoi polyhedra, and density of states of Fe_80−xTM_xB₂₀ (x = 0, 10, 20, 30, and 40 at.%, TM(Transition Metal): Co, Ni) amorphous alloys were calculated. The results show that with the increase in Co content, the saturation magnetization of Fe_80−xCo_xB₂₀ (x = 0, 10, 20, 30, and 40 at.%) amorphous alloys initially increases and then decreases upon reaching the maximum at x = 10 at.%, while for Fe_80−xNi_xB₂₀ (x = 0, 10, 20, 30, and 40 at.%), the saturation magnetization decreases monotonously with the increase in Ni content. Accordingly, for the two kinds of amorphous alloys, the obtained simulation results on the variation trends of the saturation magnetization with the change in alloy composition are in good agreement with the experimental observation. Furthermore, the relative maximum magnetic moment was recorded for Fe₇₀Co₁₀B₂₀ amorphous alloy, due to the induced increased magnetic moments of the Fe atoms surrounding the Co atom in the case of low Co dopant, as well as the increase in the exchange splitting energy caused by the enhancement of local atomic symmetry.