New Journal of Physics (Jan 2014)
The role of space charge in spin-resolved photoemission experiments
- A Fognini,
- G Salvatella,
- T U Michlmayr,
- C Wetli,
- U Ramsperger,
- T Bähler,
- F Sorgenfrei,
- M Beye,
- A Eschenlohr,
- N Pontius,
- C Stamm,
- F Hieke,
- M Dell'Angela,
- S de Jong,
- R Kukreja,
- N Gerasimova,
- V Rybnikov,
- H Redlin,
- J Raabe,
- A Föhlisch,
- H A Dürr,
- W Wurth,
- D Pescia,
- A Vaterlaus,
- Y Acremann
Affiliations
- A Fognini
- Laboratory for Solid State Physics , ETH Zurich, 8093 Zurich, Switzerland
- G Salvatella
- Laboratory for Solid State Physics , ETH Zurich, 8093 Zurich, Switzerland
- T U Michlmayr
- Laboratory for Solid State Physics , ETH Zurich, 8093 Zurich, Switzerland
- C Wetli
- Laboratory for Solid State Physics , ETH Zurich, 8093 Zurich, Switzerland
- U Ramsperger
- Laboratory for Solid State Physics , ETH Zurich, 8093 Zurich, Switzerland
- T Bähler
- Laboratory for Solid State Physics , ETH Zurich, 8093 Zurich, Switzerland
- F Sorgenfrei
- Laboratory for Solid State Physics , ETH Zurich, 8093 Zurich, Switzerland
- M Beye
- Institut für Methoden und Instrumentierung der Forschung mit Synchrotronstrahlung , Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, D-12489 Berlin, Germany
- A Eschenlohr
- Institut für Methoden und Instrumentierung der Forschung mit Synchrotronstrahlung , Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, D-12489 Berlin, Germany; Universität Duisburg-Essen , Fakultät für Physik, D-47048 Duisburg, Germany
- N Pontius
- Institut für Methoden und Instrumentierung der Forschung mit Synchrotronstrahlung , Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, D-12489 Berlin, Germany
- C Stamm
- Institut für Methoden und Instrumentierung der Forschung mit Synchrotronstrahlung , Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, D-12489 Berlin, Germany; Department of Materials , ETH Zurich, 8093 Zurich, Switzerland
- F Hieke
- Institut für Experimentalphysik and Center for Free-Electron Laser Science, Universität Hamburg , D-22607 Hamburg, Germany
- M Dell'Angela
- Institut für Experimentalphysik and Center for Free-Electron Laser Science, Universität Hamburg , D-22607 Hamburg, Germany
- S de Jong
- SLAC National Accelerator Laboratory , Menlo Park, CA 94025, USA
- R Kukreja
- SLAC National Accelerator Laboratory , Menlo Park, CA 94025, USA
- N Gerasimova
- DESY , D-22607 Hamburg, Germany; European XFEL GmbH, D-22761 Hamburg , Germany
- V Rybnikov
- DESY , D-22607 Hamburg, Germany
- H Redlin
- DESY , D-22607 Hamburg, Germany
- J Raabe
- Paul Scherrer Institute , 5232 Villigen, Switzerland
- A Föhlisch
- Institut für Methoden und Instrumentierung der Forschung mit Synchrotronstrahlung , Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, D-12489 Berlin, Germany
- H A Dürr
- SLAC National Accelerator Laboratory , Menlo Park, CA 94025, USA
- W Wurth
- Institut für Experimentalphysik and Center for Free-Electron Laser Science, Universität Hamburg , D-22607 Hamburg, Germany
- D Pescia
- Laboratory for Solid State Physics , ETH Zurich, 8093 Zurich, Switzerland
- A Vaterlaus
- Laboratory for Solid State Physics , ETH Zurich, 8093 Zurich, Switzerland
- Y Acremann
- Laboratory for Solid State Physics , ETH Zurich, 8093 Zurich, Switzerland
- DOI
- https://doi.org/10.1088/1367-2630/16/4/043031
- Journal volume & issue
-
Vol. 16,
no. 4
p. 043031
Abstract
Spin-resolved photoemission is one of the most direct ways of measuring the magnetization of a ferromagnet. If all valence band electrons contribute, the measured average spin polarization is proportional to the magnetization. This is even the case if electronic excitations are present, and thus is of particular interest for studying the response of the magnetization to a pump laser pulse. Here, we demonstrate the feasibility of ultrafast spin-resolved photoemission using free electron laser (FEL) radiation and investigate the effect of space charge on the detected spin polarization. The sample is exposed to the radiation of the FEL FLASH in Hamburg. Surprisingly, the measured spin polarization depends on the fluence of the FEL radiation: a higher FEL fluence reduces the measured spin polarization. Space-charge simulations can explain this effect. These findings have consequences for future spin-polarized photoemission experiments using pulsed photon sources.
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