Magnetization process in Permalloy multilayer films

The magnetization process in positively coupled double and multilayered systems of Permalloy separated by carbon layers has been investigated. Domain patterns appearing in this process have been observed by both Lorentz electron microscopy and high-resolution Kerr effect. The patterns display a microstructure different from that observed in the single films, e.g., twin walls with crossing points, quasi-walls, superimposed cross and circular Bloch lines, and 360 degrees walls. The origin of the observed structures is analyzed. The effects of magnetic flux closure are shown.