ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
A Co/Pt multilayer is one of the most attractive candidates for next-generation high-density magneto-optical recording media. With a decreasing Co layer thickness, the direction of the easy axis of magnetization changes from in-plane to out-of-plane. We have measured core-level MCD of Co/Pt multilayers. Six Co/Pt multilayer samples were prepared which had Co layer thicknesses from 3 to 14 A(ring). The MCD experiments were made using circularly polarized undulator radiation.The spectra were taken separately for the energy regions around the Co M2,3 (and Pt O3) and Pt N6,7 (and Pt O2) edges. The dichroic signals in reflectivity were recorded for two opposite directions of an external magnetic field of 2 T. We have also measured the reflectivity spectra down to 4 eV and have made Kramers–Kronig analyses to obtain the dielectric tensor. The dielectric tensor element which represents absorption MCD shows a dramatic change at the Co M2,3 edges. The MCD spectra of thinner Co-layer samples are more asymmetric than those of thicker ones. This shows that the orbital magnetic moment of Co is enhanced as the Co layer thickness decreases. The MCD spectra become sharper and narrower with a decreasing Co layer thickness. This feature strongly reflects a band narrowing of the Co 3d state at or around the Co/Pt interfaces. The MCD spectra at the Pt N6,7 edges show little dependence on the Co layer thickness. This can be explained by assuming that Pt atoms only at the interfaces are responsible for the MCD signals, since the surface density of Pt atoms is equal for all the samples. Combining the result at the Co M2,3 edges with that at the Pt N6,7 edges leads to the conclusion that perpendicular magnetic anisotropy mainly depends on the electronic structure of Co at Co/Pt interfaces and that Pt atoms at the interfaces play a partial role in magnetic anisotropy. © 1996 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.362226
