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

Abstract

We have prepared Fe 80Er x B 20− x and Fe 74− x Al x Er 6B 20 amorphous ribbons by melt spinning device. We performed some magnetic measurements (magnetization versus temperature, magnetization versus magnetic field,⋯) on these samples and we introduced theoretical models to determine the origin of their magnetic properties concerning exchange and anisotropy energies. Then using mean-field theory, we have explained temperature dependence of magnetization and evaluated exchange interactions ( J Fe–Fe, J Fe–Er and J Er–Er). Applying the random anisotropy model to magnetization versus field curves at the approach to the magnetic saturation, we determined some fundamental parameters such as exchange ( H Ex) and random anisotropy ( H R) fields, random anisotropy constant K loc, and the ferromagnetic correlation length ( R F). We have also evaluated a new model to study the magnetic anisotropy of a ferrimagnetic and ferromagnetic systems, we distinguish between weak and strong anisotropy systems and we obtain good results in agreement with previous works on intermetallic compounds. Using this model we explain the strange behaviour of our alloy's magnetic anisotropy versus temperature. All results show that our systems are ferrimagnets with wandering axes.