Structural and magnetic properties of Pt in Co/Pt multilayers

[Co(30 Å)/Pt(x Å)]20 multilayers with the Pt layer thicknesses varying from 5 Å to 20 Å were characterized structurally by high angle X-ray diffraction, X-ray reflectivity, X-ray absorption spectroscopy and magnetically by X-ray magnetic circular dichroism. It is found that the structure and magnetic properties of Pt have a strong correlation with the Pt layer thickness. The 20 Å thickness Pt layer is not almost influenced by the adjacent Co layer and the nearest neighbors are dominated by Pt–Pt shells. With decreasing Pt layer thickness, the nearest neighbors are gradually dominated by Pt–Co shells and the Pt–Co intermixing regions also remarkable increase at the interfaces, especially for the 5 Å thickness Pt layer. The orbital and spin magnetic moments as well as the ratio morb/mspin all decrease systematically with increasing Pt layer thickness, indicating that the interface atoms are polarized by direct Pt–Co hybridization, but that the adjacent layers are polarized by Pt–Pt interactions.