Core-level magnetic circular dichroism in Co/Pt multilayers with varying Co-layer thicknesses

Magnetic circular dichroism (MCD) has been studied on Co/Pt multilayers at and around the Co M(2,3) and Pt N-6,N-7 and O-2,O-3 core-absorption edges using; directly characterized circularly polarized undulator radiation. The thickness of the Co layer(t(Co)) was varied between 3 - 14 Angstrom, with an almost constant Pt-layer thickness. We have also measured the reflectivity spectra down to 4eV and have made Kramers-Kronig analyses to obtain the dielectric tenser. The orbital magnetic moment of Co is enhanced for samples with thinner Co layers. Magnetic moments are induced on Pt atoms and ferromagnetically coupled with those on Co atoms. The Co M2,3 MCD for samples with perpendicular magnetic anisotropy(t(Co) < 7 Angstrom) is markedly different from that for samples with in-plane magnetic anisotropy(t(Co) > 7 Angstrom).