Magnetic anisotropy in evaporated amorphous films of the ternary system Gd_x(Fe_1-yCo_y)_1-x

Magnetic anisotropy has been determined for evaporated amorphous films of Gdx(Fe1-yCoy)1-x with 0.08<x<0.35 and 0.06<y<0.62. The anisotropy data were fitted with a dipolar equation of the form Ku=J CijMiM j in which Cij is a dipolar coupling constant for the i-j pair and Mi and Mj are sublattice magnetizations. The model satisfactorily described the experimental data for all films that were amorphous. The anisotropy could be attributed to pair ordering in which rare earth-transition metal pairs (Gd-Co) and Gd-Fe) contribute to in-plane anisotropy and rare earth-rare earth (Gd-Gd) and transition metal-transition metal (Fe-Fe, Co-Co, and Fe-Co) pairs contribute to perpendicular anisotropy. The Fe-Co pairs were the strongest contributor to perpendicular anisotropy with CFe-Co=2.809, CFe-Fe=0.992, and CCo-Co=0.660.