Regensburg 2022 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
MA: Fachverband Magnetismus
MA 35: Poster 2
MA 35.33: Poster
Donnerstag, 8. September 2022, 16:00–18:00, P4
Ultrafast Tunnel Magnetoresistance — •Thomas Jauk1, Kazma Komatsu1, Hana K. Hampel1, Jana Kredl2, Jakob Walowski2, Florian Lackner1, Sangeeta Sharma3, Markus Münzenberg2, and Martin Schultze1 — 1Institute of Experimental Physics, Graz University of Technology, Graz, Austria — 2Institute of Physics, University of Greifswald, Greifswald, Germany — 3Max Born Institute, Berlin, Germany
Magnetic tunnel junctions (MTJ) have been arousing ongoing interest due to their peculiar spin-transfer mechanism since the discovery of the large tunnel magnetoresistance. However, a complete microscopic understanding of the underlying physics is still lacking. We put the spotlight on the interface between a MgO-based tunnel barrier and a CoFeB wedge-like electrode in order to disentangle intertwined phenomena which come along with ultrafast demagnetization. By employing circularly-polarized visible light pulses and utilizing magnetic circular dichroism in a two-photon-photoemission (2PPE) experiment we establish a direct route to the buried interface, providing insight into the spatial arrangement and the electronic behaviour of the magnetic pattern near the Fermi level. Beside the typical demagnetization curve we observe a light-induced increase in magnetic moment for specific energy/momentum intervals. Together with DFT calculations we try to shed light on the microscopic processes involved in the ultrafast demagnetization and, especially, emphasize on the peculiarity of MTJs acting as an energy- and spin-filter.