Magnetic X-ray scattering experiments at resonant energies
The cross-sections for magnetic scattering of electromagnetic radiation were derived many years ago but are in general about 1.0 E-6 of the familiar cross-sections for charge scattering. The X-ray technique complements the more usual technique of neutron scattering, enabling separate spin and orbital moments, and the use of high intrinsic wavevector resolution to observe subtle effects in both the magnetic and crystal structures. Resonant magnetic scattering occurs when the incident photon energy is tuned to certain absorption edges. Consequential enhancement of the intensity makes it of particular importance in the study of f-element magnetism. Resonance occurs when an electron is excited into a shell containing spin-polarised electrons. The resonance itself is examined to learn whether the predominant atomic physics description contains information on the condensed-matter properties of the material. The intensities of the magnetic reflections are shown as a function of energy, as the latter is varied through the M(V) and M(IV) absorption edges for the antiferromagnets USb and NpAs. The ratio of the intensities at the two edges has been shown to be a sensitive measure of the 5f-occupancy and degree of crystal-field mixing in the electronic ground-state wavefunctions.
Bibliographic Reference: Paper presented: ALS Workshop, Berkeley (US), October 1-2, 1992
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Record Number: 199211492 / Last updated on: 1994-11-29
Original language: en
Available languages: en