TY  - EJOUR
AU  - Marotzke, S.
AU  - Gupta, D.
AU  - Wang, R. -P.
AU  - Pavelka, M.
AU  - Dziarzhytski, S.
AU  - Schmising, C. von Korff
AU  - Jana, S.
AU  - Thielemann-Kühn, N.
AU  - Amrhein, T.
AU  - Weinelt, M.
AU  - Vaskivskyi, I.
AU  - Knut, R.
AU  - Engel, D.
AU  - Braune, M.
AU  - Ilchen, M.
AU  - Savio, S.
AU  - Otto, T.
AU  - Tiedtke, K.
AU  - Scheppe, V.
AU  - Rönsch-Schulenberg, J.
AU  - Schneidmiller, E.
AU  - Schüßler-Langeheine, C.
AU  - Dürr, H. A.
AU  - Beye, M.
AU  - Brenner, G.
AU  - Pontius, N.
TI  - First experiments with ultrashort, circularly polarized soft X-ray pulses at FLASH2
IS  - arXiv:2502.03301
M1  - PUBDB-2025-00857
M1  - arXiv:2502.03301
PY  - 2025
AB  - Time-resolved absorption spectroscopy as well as magnetic circular dichroism with circularly polarized soft X-rays (XAS and XMCD) are powerful tools to probe electronic and magnetic dynamics in magnetic materials element- and site-selectively. Employing these methods, groundbreaking results have been obtained for instance for magnetic alloys, which helped to fundamentally advance the field of ultrafast magnetization dynamics. At the free electron laser facility FLASH key capabilities for ultrafast XAS and XMCD experiments have recently improved: In an upgrade, an APPLE-III helical afterburner undulator was installed at FLASH2 in September 2023. This installation allows for the generation of circularly polarized soft X-ray pulses with a duration of a few tens of femtoseconds covering the L3,2-edges of the important 3d transition metal elements with pulse energies of several uJ. Here, we present first experimental results with such ultrashort X-ray pulses from the FL23 beamline employing XMCD at the L-edges of the 3d metals, Co, Fe and Ni. We obtain significant dichroic difference signals indicating a degree of circular polarization close to 100
KW  - Materials Science (cond-mat.mtrl-sci) (Other)
KW  - FOS: Physical sciences (Other)
LB  - PUB:(DE-HGF)25
DO  - DOI:10.3204/PUBDB-2025-00857
UR  - https://bib-pubdb1.desy.de/record/624388
ER  -