Regensburg 2022 – scientific programme
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MA: Fachverband Magnetismus
MA 25: Ultrafast Magnetization Effects 2
MA 25.2: Talk
Wednesday, September 7, 2022, 15:15–15:30, H43
Non-thermal optical generation of non-collinear magnetic phase in insulating ferrimagnetic iron garnet — •Sergii Parchenko1, Antoni Frej2, Hiroki Ueda1, Robert Carley1, Laurent Mercadier1, Natalia Gerasimova1, Giuseppe Mercurio1, Justine Schlappa1, Alexander Yaroslavtsev1, Naman Agarwal1, Andreas Scherz1, Andrzej Stupakiewicz2, and Urs Sergii3 — 1European Free Electron Laser, Schenefeld, Germany — 2University of Bialystok, Bialystok, Poland — 3Paul Scherrer Institute, Villigen, Switzerland
For a long time, nearly all experimental examples of magnetic switching by femtosecond pulses were demonstrated on metals and relied on mechanisms directly related to laser-induced heating close to the Curie temperature. The discovery of all-optical magnetization switching in Co: doped iron garnets via photomagnetic effect opened a new approach for magnetization control and raised a question about the microscopic nature of photo-magnetic spin dynamics. In order to reveal the magnetization dynamic of individual sublattices after excitation with NIR ultrashort laser pulses, we implement time-resolved XMCD techniques in a soft x-ray regime. We found that the dynamics of two antiferromagnetically coupled magnetic moments are drastically different during the first picosecond after the NIR excitation. The dynamics of Fe in tetrahedral oxygen surroundings showed a fast component lasting for about a picosecond. We state that the observed photoinduced noncolinear magnetic phase might be crucial for the all-optical magnetization switching in this material.