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MA: Fachverband Magnetismus
MA 5: Surface Magnetism and Topological Insulators (joint session MA/TT)
MA 5.1: Talk
Monday, March 9, 2026, 09:30–09:45, POT/0351
Impact of keV He-ion bombardment on the magnetic proximity effect in Pt/Fe bilayers — •Mika Ossenschmidt1, Arne Vereijken1, Yahya Shubbak1, Varun Vanakalapu1, Maik Gaerner2, Arno Ehresmann1, and Timo Kuschel2 — 1University of Kassel, Germany — 2Bielefeld University, Germany
The static magnetic proximity effect (MPE) describes the occurrence of spin polarization at the interface of nominally paramagnetic materials caused by its adjacency to a ferromagnetic material. KeV-He light ion bombardment (IB) of thin-film interfaces offers the opportunity to modify the interface properties of thin-film systems without destroying the thin films, e.g., as shown for exchange-bias systems [1].
Samples of Pt 4 nm/Fe 10 nm//MgO(001) were fabricated by sputter deposition and the subsequent IB was performed with 10 keV He+ ions with a varying ion dose from 1015 to 1017 ions/cm2 in a few steps. To analyze the strength of the MPE in Pt, x-ray resonant magnetic reflectivity measurements were performed at the Pt L3 absorption edge (11.567 keV) at DESY beamline P09 [2].
The fits of the x-ray reflectivity measurements provide a significant difference for the roughness σ of the Pt-Fe interface due to IB while substrate and surface roughnesses as well as layer thicknesses remained nearly unchanged. The resulting maximum Pt moment at the interface for the sample with IB is higher than without IB, due to the increasing intermixing of Pt and Fe atoms at the Pt-Fe interface.
[1] Ehresmann et al., J. Phys. D: Appl. Phys. 38, 801 (2005)
[2] Kuschel et al., Phys. Rev. Lett. 115, 097401 (2015)
Keywords: magnetic proximity effect; ion bombardment; x-ray resonant magnetic reflectivity