Abstract
The spin-dependent absorption of circularly polarized x-rays is studied at theL-edges of ferromagnetic Gd and Tb metal. At theL 1-edge a spin-dependent part of the absorption coefficient of 10−3–10−2 is observed. Strong resonance absorption known as “white line” occurs at theL 2- andL 3-absorption onset. Correlated with it one finds large spin-dependent absorption effects with amplitudes of a few percent. The spin-dependent absorption spectra reflect the profiles of the spin densities of the states populated in the absorption process. Thep-states show spin densities correlated with the first two flat bands above the Fermi level. The spin density of thed-like states is concentrated in the energy range of the white line. In Gd a splitting of ∼(0.5–0.6) eV of the unoccupied 5d spin up and spin down bands is indicated for both spin-orbit partners. In Tb a large dependence of the 5d spin density on the spin-orbit configuration is observed. The experimental results on the spin densities in Gd are compared with band structure calculations for the ferromagnetic ground-state. The theoretical and experimental spin density profiles agree well for thep-states but not for thed-states. The discrepancy concerning thed-states may be attributed to core-hole polarization effects in the absorption process.
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Schütz, G., Knülle, M., Wienke, R. et al. Spin-dependent photoabsorption at theL-edges of ferromagnetic Gd and Tb metal. Z. Physik B - Condensed Matter 73, 67–75 (1988). https://doi.org/10.1007/BF01312156
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DOI: https://doi.org/10.1007/BF01312156