Control of vortex pair states by post-deposition interlayer exchange coupling modification

In this work we report on both, the global and the micromagnetic properties of interlayer exchange coupled spin systems. We apply ion irradiation as a post-deposition method to modify the coupling strength and orientation in trilayer films that consist of two ferromagnetic layers and a nonmagnetic interlayer. For the macroscopic coupling constants we observe a transition from antiferromagnetic to ferromagnetic coupling with increasing ion fluence. The microscopic coupling is directly imaged for the model system of layered vortex pairs in patterned trilayer elements by x-ray microscopy. We find that the macroscopic coupling constant determines the orientation of the in-plane magnetization circulations, resulting in a homogenous in-plane coupling angle throughout the structure. For the vortex cores however, both polarity orientations are stable, due to the significant demagnetization fields present