Regensburg 2019 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 51: Magnetism Poster B

MA 51.60: Poster

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

Spatially resolved observation of helicity dependent switching by PEEM — •Nina Novakovic¹, Mohamad A. Mawass¹, Alexander Steigert¹, Oleksii Volkov², Denys Makarov², and Florian Kronast¹ — ¹Helmholtz-Zentrum Berlin für Materialien und Energie, 12489, Berlin, Germany — ²Helmholtz-Zentrum Dresden-Rossendorf e. V., Institute of Ion Beam Physics and Materials Research, 01328 Dresden, Germany

Controlling the magnetization by light as opposed to magnetic fields has appeared as a promising alternative to current magnetic data storage technologies as it may lead to faster and denser memory devices. It has been shown that circularly polarized femtosecond laser pulse can switch the magnetization of a thin film as function of laser helicity. Such effect is known as all-optical helicity dependent switching (AO-HDS).

We combine excitation by a diffraction limited laser spot with photoelectron emission microscopy to study AO-HDS on *m to nm length scale. Imaging the magnetic state before, during and after excitations by an ultrafast laser pulse allows us to observe helicity and relaxation driven effects. We will demonstrate all-optical switching in various systems from FeTb ferrimagnetic films to CoPt multilayers and discuss novel effects such as a thickness dependent inversion of the driven direction of AO-HDS. The research was done at the UE49PGMa beamline at BESSY II Synchrotron facility at Helmholtz-Zentrum Berlin using the SPEEM station.