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Multilayer samples of Ce/Fe and Ce/FeCoV, fabricated by sputtering and characterized by means of x-ray diffraction and reflectivity, were studied by 57Fe Mössbauer spectroscopy and polarized neutron reflectivity. In the Ce/Fe system a paramagnetic Fe phase is observed at room temperature for Fe thicknesses below 20 Å. This phase is ordered at 4.2 K, and is attributed to amorphous Fe at the interface with Ce. In contrast, the Ce/FeCoV system is ferromagnetic at room temperature for all layer thicknesses studied. From the relative intensity of the Mössbauer lines we show that both systems exhibit a perpendicular magnetic anisotropy for magnetic layers of less than 17 Å thickness, indicating a positive interface anisotropy constant, KS. For a selection of Ce/Fe samples, the reorientation of the magnetic moments in magnetic fields applied normal to the layers enabled the magnetic anisotropy energy Keff of each sample to be evaluated. The trend of the values of Keff gave volume and interface anisotropy constants KV = 1.1 (±1.2)×105 J m-3 and KS = 0.98 (±0.15)×10-3 J m-2 for the Ce/Fe system, where the positive values indicate a preference for an out-of-plane orientation of the magnetization.

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Multilayer samples of Ce/Fe, fabricated by sputtering and characterized by X‐ray diffraction and reflectivity were studied by polarized neutron reflectivity and Mössbauer spectroscopy. Corresponding studies on sputtered U/Fe multilayers have been initiated. In Fe/Ce a paramagnetic phase, identified as amorphous Fe was observed at Fe thicknesses below 20 Å. Perpendicular magnetic anisotropy was observed for Fe thicknesses below 17 Å and studies in applied fields enabled magnetic anisotropies to be evaluated for Fe thicknesses up to 40 Å. The Ce/Fe interface anisotropy was evaluated as Ks = (0.98 ± 0.15) × 10—3 Jm—2, among the largest values reported. Neutron reflectivity results did not observe magnetic moments on Ce layers. Preliminary measurements on U/Fe multilayers have not observed induced moments on the U layers.