Interlayer exchange coupling and magnetic reversal in Co/Pt multilayers

The interlayer exchange couplings in Co/Pt multilayers with perpendicular anisotropy prepared by direct-current magnetron sputtering have been investigated. In the Co(5 Å)/Pt(tPt Å)/Co(5 Å) multilayers, the interlayer exchange coupling oscillates between antiferromagnetic and ferromagnetic as a function of Pt spacer thickness when the Pt spacer thickness tPt>34 Å. Investigation of the temperature dependent interlayer coupling in Co(5 Å)/Pt(37 Å)/Co(5 Å) shows a antiferromagnetic to ferromagnetic transition at 130 K, and this is related to the temperature dependent polarization of the Pt layer in the Co/Pt multilayer. By increasing the Pt spacer thickness, it has been found that interlayer exchange couplings of [Co(5 Å)/Pt(tPt Å)]3 multilayers transfer from ferromagnetic to antiferromagnetic. The relative magnetization orientation of the three Co layers in [Co(5 Å)/Pt(36 Å)]3 multilayer could reverse separately with magnetic field.

► We find antiferromagnetic interlayer exchange coupling in [Co/Pt]3 multilayers.
► We could control the magnetic reversals of the Co layers in [Co/Pt]3 separately.
► Oscillatory IEC between AF and FM in Co/Pt films is observed for the first time.
► Temperature dependent polarization of Pt causes IEC transition in Co/Pt multilayer.