Agenda

Prochain séminaire LANEF/Matériaux Quantiques :

Jeudi 17 octobre 2024 à 14h00

Simone Finizio (PSI, Switzerland)

“ Bright days ahead – Soft X-ray scanning microscopy at 4th generation lightsources “

Pour accéder à ce séminaire :

Institut Néel CNRS, Bâtiment E, Salle Louis Weil  (E424)

Résumé : X-ray microscopy has been, over the last decades, a vital tool in experimental condensed matter physics, thanks to the possibility of combining high spatial resolutions (given by the short wavelength of X-ray photons) with elemental sensitivity (by tuning the X-ray energy to specific elemental absorption edges), and several dichroic effects (such as X-ray magnetic circular dichroism – XMCD – and X-ray linear dichroism – XLD). Various X-ray microscopy techniques, such as photoemission electron microscopy, scanning transmission X-ray microscopy (STXM), and ptychography exist, and have been extensively used for the investigation of condensed matter physics systems, such as e.g. nanostructured magnetic materials.
The availability of monochromatic, high-brilliance, and coherent X-ray beams is of vital importance for the acquisition of high-quality microscopy images, and synchrotron light sources have been used since decades for the generation of such X-ray beams. Nowadays, many synchrotron light sources are undergoing, or planning to undergo, upgrades towards a novel storage ring designed, called diffraction limited storage rings (DLSR), or 4th generation light sources. DLSRs offer several orders of magnitude of increase in the coherent photon flux over the entire energy range, which would enormously benefit X-ray microscopy imaging.
For example, the increase in the coherent photon flux will allow for the routine acquisition of high-resolution STXM images, as this will tackle all of the issues occurring for high-resolution X-ray optics. In addition, the combined increase in coherent photon flux, in the available (GPU) computational power, and in the performances of 2D soft X-ray detectors will also enable for the routine performing of high-resolution soft X-ray ptychographic imaging.
In this presentation, I will give first of all an overview of two scanning X-ray microscopy techniques, namely STXM and soft X-ray ptychography imaging, with particular attention at how these techniques can be used to image the dynamics of magnetic systems in three dimensions. Then, I will present the current status of the commissioning of a new combined STXM and soft X-ray ptychography endstation at the SoftiMAX beamline of the MaxIV DLSR, and the first results in the ptychographic imaging of the magneto-electric coupling between ferroelectric domains and spin cycloid in freestanding BiFeO3 thin films, which fully exploit the sub-5nm spatial resolutions achievable with the technique.

Les organisatrices :

Elsa Lhotel (elsa.lhotel@neel.cnrs.fr)
Florence Levy-Bertrand (florence.levy-bertrand@neel.cnrs.fr)