Origin of magnetic field-induced magnetic anisotropy in amorphous CoFeB thin films

Magnetic anisotropy (MA) is an important property of magnetic materials, which not only determines the orientation of the magnetic moment in the magnetic material but also influences the working frequency of magnetoelectric devices. Unrevealing the origin of MA has become an important topic and attracts lasting interest. Here, we report a quite significant magnetic field-induced uniaxial MA in amorphous CoFeB thin films containing double ferromagnetic atoms. The thickness independence of MA was obtained by observing a series of hysteresis loops and magnetic domains. The MA is proved subtly to be related to the variation of orbital magnetic moment acquired by ferromagnetic resonance. Furthermore, we found that atoms combine into clusters and incline to an order in amorphous CoFeB thin films with field-induced MA. Based on these experimental results, we proposed a direction-like order model to interpret the origin of magnetic field-induced MA in amorphous CoFeB thin films well.