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    Thickness and angular dependence of the L-edge X-ray absorption of nickel thin films
    (WILEY-BLACKWELL, 2011) Ufuktepe, Y.; Akgul, G.; Aksoy, F.; Nordlund, D.
    We report on the near-edge X-ray absorption fine structure spectroscopy of the L(3) (2p(3/2)) and L(2) (2p(1/2)) edges for ferromagnetic pure nickel transition metal and show that the L(2,3) edge peak intensity and satellite feature at similar to 6 eV above the L(3) edge in nickel increase with increasing nickel film thickness both in the total electron yield and transmission modes. The absorption spectra of nickel metal, however, exhibit strong angular-dependent effects when measured in total electron yield mode. In addition, we calculated the mean electron escape depth of the emitted electrons (lambda(e)), which was found for pure nickel metal to be lambda(e) = 25 +/- 2 angstrom. We point out the advantages of the total electron yield technique for the study of the L-edge of 3d transition metals. Copyright (C) 2011 John Wiley & Sons, Ltd.
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    Thickness dependence of the L-2,L-3 branching ratio of Cr thin films
    (ELSEVIER SCIENCE SA, 2010) Aksoy, F.; Akgul, G.; Ufuktepe, Y.; Nordlund, D.
    We report the electronic structure of chromium (Cr) thin films depending on its thickness using two measures, total electron yield (TEY) and transmission yield mode. The Cr L edge X-ray absorption spectroscopy (XAS) spectrum shows strong thickness dependence with broader line widths observed for L-2,L-3 edge peaks for thinner films. The white line ratio (L-3/L-2) was found to be 1.25 from the integrated area under each L-3 and L-2 peak and 1.36 from the ratio of the amplitudes of each L-3 and L-2 peak after the deconvolution. Additionally, we show that full-width at half-maximum (FWHM) at the L-2 and L-3 edges and the branching ratio of Cr change as a function of film thickness and these are discussed in detail. Using L-2,L-3 resonance intensity variation as a function of film thickness we calculated the electron escape depth and X-ray attenuation length in Cr. Comparing our results with the literature, there was good agreement for the L-3-L-2 ratio although the detailed shape can show additional solid state and atomic effects. (c) 2010 Elsevier B.V. All rights reserved.