THE NONRESONANT MAGNETIC-X-RAY SCATTERING CROSS-SECTION OF MNF2 .1. MEDIUM X-RAY-ENERGIES FROM 5 TO 12 KEV

To demonstrate the possibilities of non-resonant magnetic X-ray diffra ction, data taken on the antiferromagnetic model system MnF2 in a medi um 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 degrees Bragg reflectio n from a single crystal. The analyzer has been successfully tested on beamline W1 at HASYLAB by measuring the polarization of the primary ph oton beam and of the 400 charge peak of an MnF2 single crystal. Subseq uently, the analyzer was used to explore the polarization dependence o f the non-resonant magnetic X-ray scattering cross section of this sam ple, complemented by measurements of the directional dependencies with out polarization analysis. In the latter configuration, count rates as high as 3800 photons s(-1) and a peak-to-background ratio of 160:1 we re obtained. A method to determine the direction of the magnetic momen ts with respect to the crystalline axes is presented. The results give experimental support for the theoretical form of the nonresonant magn etic X-ray scattering cross section and at the same time provide a fea sibility test for a general magnetic structure determination.