Magnetic reversal and domain structure in perpendicular AF-coupled films

Contrary to in-plane multilayer systems with antiferromagnetic (AF) interlayer coupling perpendicular AF-coupled systems create demagnetization fields that prefer a ferromagnetic (FM) alignment of adjacent layers. This provides an opportunity to compensate AF-exchange versus demagnetization energy, thus allowing the coexistence of two very different ground states, one FM and one AF in nature. The general physics of perpendicular AF-coupled systems is introduced, discussed, and exploited via a model system: [(Co/Pt)X−1Co/Ru]N multilayers. By varying X and N we confirm experimentally the existence and stability of the two-ground-state system within a narrow transition region.