Low-Temperature Magnetization Switching of Bilayer FeNi/FeMn Films

A change in the kinetics of magnetization reversal of a bilayer ferromagnet–antiferromagnet film during a decrease in the temperature is experimentally detected. The motion of a zigzag domain wall is typical of high-temperature conditions, and the system undergoes magnetization reversal by irregular rotation at low temperatures. This phenomenon is found to occur only in a coupled system of layers with exchange anisotropy: it is absent when the antiferromagnetic layer is removed. The change in the character of magnetization reversal at low temperatures is related to the appearance of specific pinning of domain walls, which is caused by interface regions with a varying chirality of an interlayer exchange spring and a perpendicular magnetic anisotropy at interface steps.