MAGNETIC X-RAY SCATTERING AT SYNCHROTRON SOURCES

C. Vettier

European Synchrotron Radiation Facility, France

The advent of synchrotron x-ray radiation has allowed a significant development of the use of x-rays in the study of magnetic properties of solids. The performances of the new x-ray sources (flux, polarisation, energy tunability) have led to a large variety of experiments which complement neutron magnetic diffraction results. In the non- resonant regime, magnetic x-ray scattering is the only tool that allows an unambiguous determination of spin and orbital momentum form factors. In the resonant regime, the large resonant enhancements have made possible experiments that were formerly considered as impossible due to the inherent weakness of the signal.

In this review of magnetic scattering, we will describe the characteristics of magnetic x- ray scattering and we review some typical experiments that demonstrate how the x-ray methods can be applied to the study of magnetism. We will emphasize the importance of resonant scattering for the study of micro-crystals, magnetic surface ordering, thin films and near-surface effects. Similarly, the chemical sensitivity, electronic shell selectivity of the resonance make the x-ray scattering an ideal tool to identify individual magnetic moments in intermetallics and compounds as well as the contributions from different partially filled electronic orbitals to the magnetization. Recent results obtained at synchrotron sources will be presented.

The speaker is indebted to his collaborators, especially F. de Bergevin, N. Bernhoeft, A. Stunault, and D. Wermeille.