- https://www.cells.es/ca/actualitat/agenda/esdeveniments-publics-dalba/resonant-x-ray-dichroism-extinction-effect-measurement-of-chirality-and-beyond
- Resonant X-Ray Dichroism Extinction Effect. Measurement of Chirality and Beyond
- 2018-09-26T15:00:00+02:00
- 2018-09-26T16:00:00+02:00
- By Shilei Zhang From Deparment of Physics, University of Oxford, UK
- Què
- events
- Quan
-
Sep 26, 2018
de 15:00 a 16:00 (Europe/Madrid / UTC200) - On
- Sincrotró ALBA, sala Marie Curie
- Nom de contacte
- Inma Hernández
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- 935924389
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ABSTRACT
Spin spiral structures are a general type of magnetic order that occurs in a broad range of materials, spanning from rare-earth metals, helimagnets, multiferroics to thin film magnetic layers and molecular magnets. Determination of their chirality is an important, yet fun experimental task. Though this can be usually achieved in a polarized neutron/x-ray scattering experiment, chirality alone is not sufficient to describe the rich variations of the spiral motif structure. Here, we will demonstrate that circular dichroism in resonant elastic x-ray scattering provides deeper information about the detailed spin spiral motif[1,2]. In fact, there exists a special geometrical condition at which circular dichroism goes completely extinct, and such a light-matter interaction process encodes the full information about the exact magnetic structure [1]. With this experimental principle, we not only determine whether the underlying structure is left- or right-handed, but also reconstruct the full picture about the spiral structure. Another, advanced application of this principle is the study of the chiral properties of magnetic skyrmions. We will show that for skyrmions, a more general degree of freedom going beyond chirality, i.e., the helicity angle, can be determined in the same way [3]. Another upgrade of this technique is achieved by performing depth-dependence measurements. Using it in the sense of a tomography-like method, the three-dimensional skyrmion crystal structure is revealed [4]. This experimental method is applicable for all kinds of magnetic materials, thus making it an ideal tool for the study of chiral magnetic systems.
Keywords: chiral magnetic structure, skyrmions, resonant elastic x-ray scattering
References
[1] S. L. Zhang, G. van der Laan, T. Hesjedal, et al., Phys. Rev. B 96, 094401 (2017).
[2] S. L. Zhang, G. van der Laan, T. Hesjedal, et al., Nat. Commun. 8, 14619 (2017).
[3] S. L. Zhang, G. van der Laan, T. Hesjedal, et al., Phys. Rev. Lett. 120, 227202 (2018).
[4] S. L. Zhang, G. van der Laan, T. Hesjedal, et al., Proc. Natl. Acad. Sci. U.S.A. (2018);
https://doi.org/10.1073/pnas.1803367115.
