The Non-Resonant Magnetic X-ray Scattering Cross Section of MnF₂. 1. Medium X-ray Energies from 5 to 12keV

Abstract

To demonstrate the possibilities of non-resonant magnetic X-ray diffraction, data taken on the antiferromagnetic model system MnF2 in a medium X-ray energy range from 5 to 12 keV are presented. An experimental set-up for the measurement of magnetic X-ray diffraction is introduced that employs a new design for a highly flexible polarization analyzer for synchrotron X-ray diffraction based on 90° Bragg reflection from a single-crystal. The analyzer has been successfully tested on beamline W1 at HASYLAB by measuring the polarization of the primary photon beam and of the 400 charge peak of an MnF2 single-crystal. Subsequently, the analyzer was used to explore the polarization dependence of the non-resonant magnetic X-ray scattering cross section of this sample, complemented by measurements of the directional dependencies without polarization analysis. In the latter configuration, count rates as high as 3800 photons s−1 and a peak-to-background ratio of 160:1 were obtained. A method to determine the direction of the magnetic moments with respect to the crystalline axes is presented. The results give experimental support for the theoretical form of the non-resonant magnetic X-ray scattering cross section and at the same time provide a feasibility test for a general magnetic structure determination.