Random anisotropy studies in amorphous Fe80-xNixB12Si8 alloys

We have studied the magnetization of melt-spun amorphous Fe80-xNixB12Si8 alloys with 0 ≤ X ≤ 60 under high magnetic fields up to 12 MA/m, and have analyzed the results at 4.2 K, based on the random magnetic anisotropy model. The exchange constant A and the local random anisotropy constant KL are found to decrease monotonically with increasing Ni concentration. We have also extracted the length over which the local anisotropy axes show a correlation.