Dresden 2020 – scientific programme
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MA: Fachverband Magnetismus
MA 57: Posters Magnetism II
MA 57.48: Poster
Thursday, March 19, 2020, 15:00–18:00, P3
Determination of the bulk spin polarization of Fe3O4 (111) thin films by means of spin-resolved hard X-ray time-of-flight microscopy — •Matthias Schmitt1, Ozan Kirilmaz1, Sergey Chernov2, Sergey Babenkov2, Dmitry Vasilyev2, Katerina Medjanik2, Olena Fedchenko2, Yuri Matveyev3, Andrei Gloskowski3, Christoph Schlueter3, Hans-Joachim Elmers2, Gerd Schönhense2, Michael Sing1, and Ralph Claessen1 — 1Universität Würzburg, Physikalisches Institut and Würzburg-Dresden Cluster of Excellence ct.qmat, 97074 Würzburg, Germany — 2Universität Mainz, Institut für Physik, 55128 Mainz, Germany — 3DESY Photon Science, 22607 Hamburg, Germany
The electronic structure of ferrimagnetic magnetite Fe3O4 has previously been studied by spin-resolved soft X-ray photoemission [1,2]. However, the theoretically predicted spin polarization of -100% at the Fermi level [3] has never been experimentally shown. We have studied 30 nm thick Fe3O4 (111) films on ZnO(0001) using spin-resolved hard X-ray photoemission (beamline P22, PETRA III, Hamburg) with a ToF microscope [4] and a novel 3D spin detector. Benefitting from the large probing depth at photon energies of up to 5 keV surface effects like a magnetically dead layer, lowering the measured spin polarization, are negligible. We thus have been able to measure the true bulk spin polarization and discuss our findings as derived from the complex analysis of the microscopy data. [1] Phys. Rev. B 65, 064417 (2002); [2] J. Phys.: Condens. Matter 19, 315218 (2007); [3] J. Phys. Soc. Jpn. 68, 1607 (1999); [4] J. Synchr. Rad. 26, 1996 (2019)