Magnetization Reversal and Domain Replication in Co–Au–Co Film with Perpendicular Anisotropy

The Co-0.6 nm-Au-wedge (1.7-3 nm)-Co-0.6 nm layered structure was investigated using a magnetooptical Kerr effect. The analysis of major and minor hysteresis loops measured at consecutive points along the wedge of an Au spacer indicates that the structure is characterized by perpendicular anisotropy of Co layers, different switching fields, and by a continuous transition from ferromagnetic (F) to antiferromagnetic (AF) coupling. The study of the minor hysteresis loops, registered when the magnetically harder layer was only partially reversed, allowing us to prove that the process takes place through a distinct intermediate state corresponding to the copying of domains in AF or F configuration. The field range in which that the state is preserved broadens with increasing interaction irrespective of its sign.