Dependence of Interlayer AF Coupling on Ferromagnetic Layer Thickness in Pt/Co₅/Ru/Co/Pt₅ Multilayers

We study magnetization reversal in the interlayer coupled Pt/Co₅/Ru/Co/Pt₅ 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.