Magnetic x-ray dichroism in 2p absorption spectra of Fe/Cu(001)
- Lawrence Livermore National Lab., CA (United States)
- Naval Research Lab., Washington, DC (United States)
Large magnetic circular dichroism using circularly polarized synchrotron radiation was observed at L{sub 2,3} absorption edges of thin (1--12 monolayer) fcc Fe films grown on Cu(001). Dramatic changes in 2p branching ratio are observed when the orientation of photon and electron spin are varied from parallel to antiparallel. Films thicker than 2 ML grown at 150K were magnetized along the sample normal. For linearly polarized perpendicular to magnetic axis of the sample the branching ratio was 0.74. This ratio varied from 0.64 to 0.85 for photon spin parallel and antiparallel, respectively, to the magnetic axis. This effect was observed either by varying the x-ray helicity for a fixed magnetization, or by reversing the magnetization for a fixed x-ray polarization. Temperature and film thickness dependence of the perpendicular anisotropy in these films could be monitored by variations in the 2p branching ratio. Our results are consistent with other studies, but the use of off-plane circularly polarized x-rays from a bending magnet monochromator offers {approximately}2 orders of magnitude greater intensity than typical spin-polarization measurements. Finally, our results are described in a simple theoretical framework that allows a determination between predicted low- and high-spin phases for fcc Fe. Our data suggest a high-spin phase with a moment of 2.0--2.5 {mu}{sub B}/atom.
- Research Organization:
- Lawrence Livermore National Lab., CA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 10143196
- Report Number(s):
- UCRL-JC--111611; CONF-921201--15; ON: DE93009255
- Country of Publication:
- United States
- Language:
- English
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