High angle magnetic x-ray diffraction

The magnetic scattering of x-rays was first performed 30 years ago and was considered as a curiosity. However, due to the advent of high brilliance synchrotron radiation sources, this technique has become a standard microscopic probe for the investigation of magnetic properties. The magnetic x-ray scattering amplitude contains two terms: the nonresonant term that exists at all photon energies and the resonant term, induced by multipole electric transitions, that is peaked near absorption edges. In this paper, the basic concepts of x-ray magnetic scattering are first introduced for both non-resonant and resonant regimes. Then, selected examples are presented in order to illustrate several specific properties of the technique: i) high resolution in the reciprocal space; ii) ability to separate the orbital momentum contribution to magnetization; iii) chemical and electronic selectivity; iv) possibility to investigate weak moment systems and observe resonant signal for polarized non-magnetic ions; v) multi-q structure detection.