Dependence of interlayer AF coupling on ferromagnetic layer thickness in [Pt/Co]₅/Ru/[Co/Pt]₅ multilayers

We study magnetization reversal in the interlayer coupled [Pt/Co] ₅/Ru/[Co/Pt]₅ multilayers (MLs) by means of the measurement of extraordinary Hall effect (EHE). Fitting experimental data to a simple model, we determine the interlayer coupling strength for various thicknesses of the ferromagnetic layers at a fixed Ru spacer thickness. It is found that the dependence of interlayer coupling strength on the Pt layer thickness is much stronger than the previous report in the ferromagnetic/ nonmagnetic/ferromagnetic multilayers.