Regensburg 2019 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 51: Magnetism Poster B

MA 51.22: Poster

Donnerstag, 4. April 2019, 15:00–18:00, Poster C

Spin-resolved electronic structure of 3d transition metals during ultrafast demagnetization — •Beatrice Andres, Jonathan Weber, Wibke Bronsch, and Martin Weinelt — Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin

Spin-resolved experiments on magnetization dynamics are still rare. Few photoemission works have been published, which show not only spin- but also energy-resolved magnetization dynamics [1-3]. Refs. [1] and [3] demonstrated that in one material spin dynamics can be very different for the various electronic states and thus the outcome of any ultrafast demagnetization experiment depends on the probed electronic states. This emphasizes the importance of spin-resolved measurements in magnetization dynamics.

Continuing the research of these works, here we present new results on the ultrafast demagnetization of thin Fe films on W(110). In laser photoemission (hν_Probe = 6.2 eV) we find an ultrafast breakdown of the spin polarization after pumping the system with 70-fs pulses at hν_Pump = 1.6 eV. Measuring a minority-spin surface resonance close to the Fermi level at ∼ 0.1 Å⁻¹ in Γ-H direction, we observe only marginal changes in binding energy, while there is a pronounced drop of spin polarization. These findings corroborate a band mirroring effect similar to the ones observed in Refs. [1] and [2].

[1] Gort et al., Phys. Rev. Lett. 121, 087206 (2018)

[2] Eich et al., Sci. Adv. 3, e1602094 (2017)

[3] Andres et al., Phys. Rev. Lett. 115, 207404 (2015)