Regensburg 2022 – scientific programme

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MA: Fachverband Magnetismus

MA 8: Ultrafast Magnetization Effects 1

MA 8.12: Talk

Monday, September 5, 2022, 17:45–18:00, H37

Tuning all-optical magnetization switching efficiency by laser pulse wavelength variation — •Marcel Kohlmann¹, Lucas Vollroth¹, Kristýna Hovořaková², Eva Schmoranzerová², Robin John¹, Denise Hinzke⁴, Peter Oppeneer³, Ulrich Nowak⁴, Markus Münzenberg¹, and Jakob Walowski¹ — ¹Greifswald University, Greifswald, Germany — ²Charles University, Prague, Czech Republic — ³Uppsala University, Uppsala, Sweden — ⁴Konstanz University, Konstanz, Germany

Heat-assisted magnetic recording (HAMR) presents a promising candidate for high data density devices. Leaving investigation of magnetization manipulation a topic of interest for research and development. We study all-optical helicity-dependent switching of FePt granular HAMR media[2] as an alternative writing mechanism. The latest perception of interaction of heating and ultra fast excitation suggests the contribution of magnetic dichroism and the inverse Faraday effect as interchanging driving forces behind the magnetization reversal. The switching rates for individual FePt nano particles from ab-initio calculations of the inverse Faraday effect and magnetic dichroism induced heating provide a model to describe the switching as a stochastic process. We extend the study to wavelength dependent switching experiments from 800 nm up to 1550 nm for all-optical writing experiments on FePt granular media evaluating the writing efficiency.
We greatly acknowledge the DFG funding within the project "Fundamental aspects of all-optical single pulse switching in nanometer-sized magnetic storage media.