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- Hahlin, Anders, et al.
(author)
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Structure and magnetism on in-situ ultrathin epitaxial films : XMCD and EXAFS on Fe/Ag(100)
- 2003
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In: Proceedings of the 7th International Conference on Nanometer-Scale Science and Technology and the 21st European Conference on Surface Science. ; , s. 76-81
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Conference paper (peer-reviewed)abstract
- We have made in situ investigations of epitaxial ultrathin Fe films on Ag(1 0 0). This system is known to exhibit a reorientation of the magnetization, dependent of Fe thickness and temperature. Our aim here is to correlate the local structure with the magnetic properties of this system. The X-ray absorption fine structure has been recorded in situ both in the near edge as well as in the extended X-ray absorption fine structure (EXAFS) range. Using X-ray magnetic circular dichroism we find that, below 300 K, films between 2 and 6 monolayers show an out-of-plane remanent magnetization whereas for thicker films the magnetization lies in-plane. By making use of the Fe L-edge EXAFS we obtain information on the local structure around the Fe atoms, such as the interatomic distances, the coordination number, and the mean square relative displacement of the first neighbor shells.
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| 2. |
- Hunter Dunn, Jonathan, et al.
(author)
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Elliptically polarised soft X-rays produced using a local bump in MAX II characterisation of the degree of polarisation
- 2004
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In: AIP Conference Proceedings. - : AIP. - 1551-7616 .- 0094-243X. ; 705, s. 65-68
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Conference paper (peer-reviewed)abstract
- MAX-lab has introduced a local perturbation to the electron orbit of the MAX II storage ring, providing users at the SX700 monochromator beam line, D1011, with elliptically polarised soft X-rays. This is achieved by using corrector magnets to send the electron orbit on an ascending or descending trajectory through the dipole magnet source. This simple "bump" approach has many advantages over and above insertion device based solutions. To illustrate the potential of the approach, the degree of circular polarisation, Pc, has both been calculated and measured. The calculation was made by applying the Stokes formalism to the intensities given by the standard dipole emission formula. Experimentally Pc was characterised using X-ray magnetic circular dichroism measurements. In such experiments magnetic contrast scales directly proportional to Pc. Using a 25 atomic layer bcc Fe film deposited on the Cu(100) surface as a calibration standard the spin moment, ms, was determined. By comparing the values of ms obtained here with those reported earlier, the degree of circular polarisation could be estimated. At ~715 eV the calculated and measured values of Pc are 0.93 and 0.85, respectively
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