Mapping magnetic domains via momentum-selective dichroism in threshold photoemission electron microscopy

Maximilian Paleschke^1,3*, Cheng-Tien Chiang¹, Frank O. Schumann², Jürgen Henk³, Wolf Widdra³

¹Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan
²Max Planck, Institute of Micostructure Physics, Halle (Saale), Germany
³Institute of Physics, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany

* Presenter:Maximilian Paleschke, email:m.paleschke@iams.sinica.edu.tw

With the progress of laser-based photoemission experiments, time-resolved, threshold photoemission electron microscopy (PEEM) at surfaces can be routinely performed in laboratory [1,2]. However, threshold PEEM measurements of ultrafast magnetization dynamics remain in its infancy as compared to well-established experiments like magneto-optical Kerr effect or X-ray dichroism. In this talk, I will present studies on Fe(001) via near-threshold PEEM with magnetic circular dichroism (MCD) as a dominant contrast mechanism. We reveal the in-plane ferromagnetic domain structure as well as details of the Fe 3d electronic band structure by state-of-the-art real-space and momentum-space images. Placing a contrast aperture in a momentum region of high magnetic asymmetry increases the ferromagnetic contrast in real space significantly. This ansatz may enable pushing the technique to ultrafast timescales in the future.

References
1. M. Paleschke, C.-T. Chiang, L. Brandt, N. Liebing, G. Woltersdorf, and W. Widdra, New J. Phys., 23, 093006, (2021)
2. M. Paleschke, Dissertation, Martin-Luther-Universität Halle-Wittenberg (2022) https://opendata.uni-halle.de/handle/1981185920/93402

Keywords: photoemission, magnetism, ultrafast, femtosecond laser, dichroism