4fand5dmagnetic moments in highly correlated [Ce/La/Fe] and [La/Ce/Fe] multilayers studied by x-ray magnetic circular dichroism

Magnetic polarization of the La and Ce5dstates near the interfaces ofFe/LaHMünzenberg1, Leuenberger2, Felsch3 et al. 2003Phys. Rev. BSelf Cite5240View full textAdd to dashboardCite

“…39 For a more detailed discussion of the case of the Fe/Ce multilayers the reader is referred to our previous publication. 50 Concerning the deconvolution of the L 2 spectra of the hydride sublayers, similar trends in the evolution of the white lines with increasing hydrogen content were observed for all multilayers. But a detailed comparison of samples with different RH x -layer thicknesses is difficult and will not be attempted here.…”

“…As a consequence, different 4 f configurations in the ground state as they exist in ␣-and ␥-Ce manifest themselves in different L 2,3 -edge spectral profiles: 39 the double-peak structure of the hydrogen-free Fe/Ce multilayer in Fig. 3 is a fingerprint of ␣-like Ce, 50 the single white line of the Fe/CeH x multilayers reflects ␥-like Ce. A simple argument explaining the different 4 f configuration in the two multilayer systems is that the insertion of hydrogen into the Ce layers expands the lattice and hence reduces the strength of the hybridization between the 4 f and (5d6s) 3 conduction-band states, which leads to a relocalization of the 4 f states.…”

“…The different line shapes in the case of Ce-L 2 spectra indicate that the absorption of hydrogen induces a change of the electronic configuration of Ce. 22,50 Even though the 4 f states do not directly participate in the dipolar transition they interact strongly with the 2p core hole and hence are involved indirectly in the photoabsorption process by intra-atomic final-state effects. As a consequence, different 4 f configurations in the ground state as they exist in ␣-and ␥-Ce manifest themselves in different L 2,3 -edge spectral profiles: 39 the double-peak structure of the hydrogen-free Fe/Ce multilayer in Fig.…”

Perpendicular magnetic anisotropy and the reorientation transition of the magnetization inCeH2/Femultilayers probed by x-ray magnetic circular dichroism

“…42 This has been observed indeed for the Ce/Fe multilayers. 14,43 The M 4,5 spectra at 300 and 10 K in Fig. 5͑b͒ are identical, hence the ␥-like 4 f configuration of Ce in the CeH 2 /Fe system with its well localized 4 f electron is not modified down to low temperatures.…”

“…They induce ordered magnetic moments on the 5d and 4 f states in the ground state of the normally paramagnetic metal CeH 2 even at room temperature and lead to a very unusual spectral shape of the Ce-L 2,3 XMCD signals. Note that this system is very different from the hydrogenfree multilayer system ͓Ce/Fe͔ϫn which is highly correlated as well 14 but does not show a PMA. 15 There is evidence that this is related to the different nature of the 4 f -electron states which are delocalized in these structures but localized in the hydride system.…”