Appearance of inverted hysteresis, pinning effect in amorphous FeCoB ribbon with annealing: A Kerr microscopy investigation

Abstract A systematic investigation has been carried out on the magnetic domain evolution and local hysteresis behavior in iron based amorphous ribbons (FeCoB) by Kerr microscopy with annealing. Explicitly, we have studied the ‘stress’ magnetic domain structure at the strained region of the ribbon, which is likely to be caused by local residual stress present in the ribbon. It is observed that the stress magnetic domain pattern gradually vanishes at elevated annealing temperature due to thermally relieving of compressive stress. Interestingly, in the same region of the ribbon, but at different ranges of temperature annealing, we have encountered different magnetic domains mechanisms and hysteresis behavior, namely domain wall pinning, inverted hysteresis behavior, and domain wall propagation. The results are explained in terms of competition between different source of anisotropy in the ribbon emerging at different annealing temperature.