INTERFACIAL MAGNETISM OF CE FE AND CEH-SIMILAR-TO-2/FE MULTILAYERS STUDIED BY FE-57 MOSSBAUER-SPECTROSCOPY/

The distribution of the magnetic hyperfine fields and the magnetic ani sotropy of Ce/Fe and CeH approximately2/Fe multilayers have been studi ed by Mossbauer spectroscopy between 4.2 and 300 K. The extension of t he Ce-Fe interaction defining a 'magnetic interface' exceeds the struc tural extension of the interface and is more than two times larger at the Ce/Fe than at the CeH approximately2/Fe interface. This is propose d to be a consequence of a strong hybridization between the Ce-5d and Fe-3d states that is suppressed by hydrogenation. From the relative in tensity of the Mossbauer lines we show that for the CeH approximately2 /Fe system with sufficiently thin Fe layers the orientation of the spo ntaneous magnetization is perpendicular to the film plane at low tempe ratures and switches to a parallel alignment at higher temperatures in a sharp transition. In contrast, the Ce/Fe system is spontaneously ma gnetized in the film plane.