The X-ray reflectivity method using a Co-Kβ line was used to analyze the layered structure of multilayers consisting of Co, Cu, CoFe, and NiFe layers. The thickness and interface width values of each layer can be obtained more accurately than in the conventional method using a Cu-Kαline, because of the anomalous dispersion effect, which enhances the X-rays reflected from the interfaces of the Co and CoFe layers. The value of δ for each layer at the Co-Kβ X-ray wavelengh was obtained from the refractive index 1-δ by analysis of the reflectivities. The δ values of Co, Cu, and NiFe were within 2% of the value calculated fom the bulk density. Careful analysis of the Co / Cu / CoFe / NiFe multilayers by the least-squares method showed that the layer thickness of 1 nm can be refined.
