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MA: Fachverband Magnetismus

MA 9: Ultrafast Magnetization Effects II

MA 9.10: Talk

Monday, March 18, 2024, 17:45–18:00, H 2013

Influence of thermal disorder on ultrafast demagnetization — •Franziska Ziolkowski, Oliver Busch, Ingrid Mertig, and Jürgen Henk — Martin Luther University Halle-Wittenberg, Halle, Germany

Ultrafast demagnetization induced by ultrashort laser pulses in magnetic materials remains a topic of intense investigation. To explain the rapid quenching of magnetization various spin flip and spin transfer mechanisms are discussed in literature. With the theoretical framework evolve [1] we investigate such ultrafast magnetization dynamics.

Our approach is based on a real-space tight-binding model and includes optical excitation as well as coupling to an external heat bath. The occupation matrix yields the system’s observables and is evolved in time by the Lindblad equation. This approach allows to reveal and to tune the relevant underlying processes.

Our study examines the influence of thermal disorder within the magnetic configuration on ultrafast demagnetization. We determine the regime of influence, which is the pertinent parameter space for this effect. Furthermore a comparison is made between spin current generation and ultrafast demagnetization in homogeneous systems versus ferromagnetic-nonmagnetic heterostructures.

[1] Töpler et al 2021 New J. Phys. 23 033042

Keywords: ultrafast; demagnetization; temperature dependence; disorder