Skript_FS05_pdf - B 5 Scattering Techniques II - Magnetic X-Ray Scattering

Oct 13, 2026

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B 5 Scattering Techniques II focuses on Magnetic X-Ray Scattering, outlining the physical motivation for magnetic contributions to x-ray diffraction in condensed matter. It explains how magnetic scattering is much weaker than charge scattering yet becomes observable using synchrotron radiation, polarization analysis, and resonance enhancement near absorption edges. The text provides an overview of relevant synchrotron-based magnetic probes, then concentrates on the non-resonant and resonant scattering cross section and the associated experimental considerations, followed by resonance exchange and non-resonant magnetic diffraction examples.

LanguageEnglish

CategoryPresentations

FormatPDF

Pages35

Reading Time12 min

AccessFree to download

Contents

1 Introduction

2 The cross section for magnetic x-ray scattering

3 Experimental consideration

4 Resonance exchange scattering

5 Non-resonant magnetic x-ray diffraction

6 Summary; comparison to magnetic neutron scattering

References

Index

B 5 Scattering Techniques II: Magnetic X-Ray Scattering Th. Brückel Institut für Festkörperforschung Forschungszentrum Jülich GmbH Contents 1 Introduction ............................................................................................... 2 2 The cross section for magnetic x-ray scattering..................................... 3 3 Experimental consideration ................................................................... 10 4 Resonance exchange scattering.............................................................. 14 5 Non-resonant magnetic x-ray diffraction ............................................. 20 6 Summary; comparison to magnetic neutron scattering......................31 References .......................................................................................................... 33 Index 35 1 Introduction Most of our present knowledge of the atomic structure of condensed matter results from x-ray diffraction studies, which probe the interaction of the electric field with the electric charge of the electron. However, since x-rays represent an electromagnetic radiation and since in magnetic materials some electrons carry a magnetic moment due to spin-and angular momentum, we naturally would expect a magnetic interaction in addition to the pure charge interaction. Even so this interaction was well established in theory [1] since Klein-Nishina 1929, the first magnetic diffraction effect was demonstrated only 1972 by de Bergevin and Brunel [2] with a commercial x-ray tube. The same authors gave a classical picture of the interaction process, deduced the detailed polarisation dependence and presented measurements on ferromagnetic compounds in a subsequent paper [3] . However, since the magnetic interaction gives just a relativistic correction to the cross section, the amplitudes of magnetic diffraction are down by approximately three orders of magnitude as compared to charge scattering, resulting in an intensity ratio of about 10-6 . Therefore magnetic x-ray scattering was considered an exotic topic until the experiments on Ho by Gibbs et al. [4], which took advantage of the high brilliance of a synchrotron radiation x-ray source thus compensating by a high photon flux at the sample position for the weak magnetic scattered intensities. The polarisation properties and the tunability of synchrotron radiation offered new perspectives for magnetic x-ray investigations. This was again demonstrated on Ho [5] by an attempt to separate spin- and angular momentum with polarisation analysis and by the observation of a resonance enhancement of the magnetic signal at the absorption edges. Nowadays, synchrotron radiation techniques for the study of properties of magnetic materials are well established. Very widespread is the application of incoherent probes which measure a macroscopic ensemble average of local magnetic properties. Among these we mention Kerrmicroscopy, measurements of the Faraday effect and the linear or circular x-ray magnetic dichroism. The Kerr-and Faraday effect measure the rotation of the plane of polarisation of an electromagnetic wave as it is reflected from or transmitted through a magnetic material, respectively. Magnetic circular dichroism describes the difference in the absorption of rightand left circularly polarised x-rays by magnetic materials. It measures essentially the same quantities as the Kerr- and Faraday effect, namely the orbital and spin contributions to the magnetic moments with element and certain site specifities. Kerr microscopy and x-ray topography are used for magnetic domain imaging. Absorption techniques become local microscopic probes when the spin resolved x-ray absorption fine structure is observed. In analogy to classical EXAFS experiments, such measurements provide information about the local environment, but are explicitly sensitive to the magnetic neighbours only. True microscopic spatial resolution is obtained with the cohe

FAQs

Why is magnetic x-ray scattering considered difficult compared to charge scattering?

Magnetic contributions are mainly a relativistic correction, so magnetic diffraction amplitudes are about three orders of magnitude smaller than charge scattering, leading to an intensity ratio near 10^-6.

How do synchrotron radiation and polarization analysis enable magnetic x-ray investigations?

High brilliance synchrotron sources provide strong photon flux to compensate for weak magnetic signals, while polarization properties and tunability allow separation of spin and angular momentum and reveal resonance enhancement at absorption edges.

What topics are addressed before the paper concentrates on diffraction cross sections?

After introducing magnetic x-ray scattering and motivating its relevance, the text surveys established synchrotron techniques for magnetic materials, then states that the following sections focus on non-resonant and resonant magnetic x-ray scattering in the cross section and discuss experimental considerations.

Oct 13, 2026

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