A new model to study the magnetic anisotropy in ternary amorphous alloys

We have prepared Fe80ErxB20-x and Fe74-xAlxEr6B20 amorphous ribbons by melt spinning device. We performed some magnetic measurements (magnetization ve rsus temperature, magnetization versus magnetic held,) on these samples and we introduced theoretical models to determine the origin of their magnetic properties concerning exchange and anisotropy energies. Then using mean-fi eld theory, we have explained temperature dependence of magnetization and e valuated exchange interactions (J(Fe-Fe), J(Fe-Er) and J(Er-Er)). Applying the random anisotropy model to magnetization versus held curves at the appr oach to the magnetic saturation, we determined some fundamental parameters such as exchange (H-Ex) and random anisotropy (H-R) fields, random anisotro py constant K-loc, and the ferromagnetic correlation length (R-F). We have also evaluated a new model to study the magnetic anisotropy of a ferrimagne tic and ferromagnetic systems, we distinguish between weak and strong aniso tropy systems and we obtain good results in agreement with previous works o n intermetallic compounds. Using this model we explain the strange behaviou r of our alloy's magnetic anisotropy versus temperature. All results show t hat our systems are ferrimagnets with wandering axes. (C) 1999 Elsevier Sci ence B.V. All rights reserved.