Interlayer Exchange Coupling In Pt/Co/Ru And Pt/Co/Ir Superlattices

Magnetic multilayer thin films with perpendicular magnetic anisotropy (PMA) and interfacial Dzyaloshinskii-Moriya interaction (iDMI) are of intense interest for realizing magnetic skyrmions and modifying topological spin textures. We systematically investigate interlayer exchange coupling (IEC) in Pt/Co/Ru(Ir) superlattices that have PMA and large iDMI. The IEC is greatly tunable by varying Ru(Ir) or Pt thickness and the antiferromagnetic IEC is as large as 1.3 mJ/m(2) that is on the same order of magnitude as the iDMI. We find unusual magnetic hysteresis loop crossing between field-ascending and -descending magnetization curves. Furthermore, we identify magnetic phase diagrams for antiferromagnetic IEC and hysteresis loop crossing with respect to Ru(Ir) and Pt thickness. Our experimental findings may open a way in the development of synthetic antiferromagnetic spintronics and/or the realization of antiferromagnetic skyrmions.