Random anisotropy studies in amorphous Co–Er–B ribbons

We have studied the magnetization of melt-spun amorphous Co80 − xErxB20 alloys with 0 ≤ x ≤ 7.5 under magnetic fields of up to 50 kOe, and have analyzed the results at 4.2 K on the basis of the random magnetic anisotropy model. The approach to saturation is established in the form of H−1/2 for various samples. The saturation magnetization, coherent anisotropy constant, local random anisotropy constant and the ferromagnetic correlation length were studied as a function of the Er composition.