AVS 46th International Symposium
    Magnetic Interfaces and Nanostructures Technical Group Tuesday Sessions
       Session MI-TuA

Paper MI-TuA5
Interatomic Effects in Resonant Photoemission in Fe/Cr Alloys and Bilayers

Tuesday, October 26, 1999, 3:20 pm, Room 618/619

Session: Magnetic Spectroscopies
Presenter: E. Arenholz, Lawrence Berkeley National Laboratory
Authors: E. Arenholz, Lawrence Berkeley National Laboratory
A.W. Kay, Lawrence Berkeley National Laboratory and Univ. of California, Davis
C.S. Fadley, Lawrence Berkeley National Laboratory and Univ. of California, Davis
Correspondent: Click to Email
Recently, first measurements and theoretical calculations of an interatomic multi-atom resonant photoemission effect (MARPE) have been reported by our group in measurements on several magnetic metal oxides (Science 281, 679 (1998)). MARPE occurs when the photon energy is tuned to a core-level absorption edge of an atom neighboring the emitting atom, with the photoemitting level having a lower binding energy than the resonant level; the resonant excitation is then found to significantly increase the photoemission intensity. We have now observed such effects in Fe/Cr alloys and bilayers. E.g. in Fe@sub 0.5@Cr@sub 0.5@, the Cr 2p intensity is enhanced by 20% when the photon energy is tuned to the Fe L@sub 3@ edge. Since MARPE is an interatomic effect the resonant enhancement of the Cr intensity in Fe/Cr alloys is expected to scale linearly with the number of Fe near neighbors. Although a monotonic decrease in the MARPE effect in Cr with decreasing Fe concentration is indeed found, deviations from the linear relationship expected from random mixing of Fe and Cr are observed. These findings will be discussed in terms of possible compositional clustering in Fe/Cr alloys, including additional data from Fe/Cr bilayers that were used to estimate the sensing length of the MARPE effect in this system. First observations of magnetic circular dichroism in the effect will also be presented.