The pinning role of nonferromagnetic B phase in the domain wall motion of ferromagnetic MnAs film on GaAs(001)

摘要

We report the pinning role of the nonferromagnetic beta phase in the domain wall motion of ferromagnetic MnAs film on GaAs(OOl) in the temperature range of 20-35 deg C. The dependence of the coercivity on the applied field direction at all temperatures was found to follow an inverse cosine law, as expected from a theoretical model considering the domain wall motion in ferromagnetic films. From this analysis, it was found that the domain wall pinning energy density increases as the temperature increases. This is ascribed to the increase in the volume fraction of the nonferromagnetic beta phase, resulting in an increase of the domain wall pinning effect during the domain wall motion.