SKM 2021 – scientific programme

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MA: Fachverband Magnetismus

MA 15: Posters Magnetism IV

MA 15.3: Poster

Thursday, September 30, 2021, 13:30–16:30, P

Tuning all-optical magnetization switching efficiency by laser pulse wavelength variation — •Marcel Kohlmann¹, Krystina Hvorakova¹, Jakob Walowski¹, Robin John¹, Cai Müller², Marco Berrita³, Deninse Hinzke⁴, Pablo Nieves⁵, Oksana Chubykalo-Fesenko⁵, Tiffany Santos⁶, Henning Ulrichs⁷, Ritwik Mondal^3,4, Peter M Oppeneer³, Ulrich Nowak⁴, Jeffrey McCord², and Markus Münzenberg¹ — ¹Greifswald University — ²Kiel University — ³Uppsala University — ⁴Konstanz University — ⁵CISC Madrid — ⁶HGST Western Digital — ⁷Göttingen University

The annual growth of created, transferred and stored data demands the development of new storage media with higher data storage density. Heat-assisted magnetic storage devices (HAMR) present a promising candidate for this application. Hence investigation of magnetization manipulation remains a topic of interest for research and development. We therefore study all-optical-helicity-dependent switching of FePt granular media which is a prominent candidate material for the development of HAMR devices. We calculated the switching rates for individual FePt nanoparticles in ab-initio calculations of inverse Faraday effect and magnetic dichroism induced heating which provided us with a model to describe the switching as a stochastic process. With this theoretical description we optimize the number of laser shots, fluence and wavelengths to all-optically switch FePt grains. First experiments show, that tuning wavelengths requires simultaneous fluence adjustment due to the increased photon absorption for larger wavelengths.