Asymmetry in the dynamics of domain walls in thin exchange-coupled ferromagnetic films

The kinetics of remagnetization after magnetic field switching was studied by the magneto-optic visualization technique in the bilayer hybrid structure composed of exchange-coupled FeNi and FeMn films. It was observed that not only the static but the dynamic characteristics of remagnetization as well depend on the polarity of a field applied along the direction of easy magnetization. The rate of the process was found to be exponentially dependent on the field strength in both directions, but the rate varied by factors of 10 upon inversion of the field. It was shown that this difference is the consequence of variation of both the time of domains nucleation and the velocity of domain walls motion.