Realistic micromagnetic description of all-optical ultrafast switching processes in ferrimagnetic alloys
arXiv:2203.15460 · doi:10.1103/PhysRevB.105.104432
Abstract
Both helicity-independent and helicity-dependent all-optical switching processes driven by single ultrashort laser pulse have been experimentally demonstrated in ferrimagnetic alloys as GdFeCo. Although the switching has been previously reproduced by atomistic simulations, the lack of a robust micromagnetic framework for ferrimagnets limits the predictions to small nano-systems, whereas the experiments are usually performed with lasers and samples of tens of micrometers. Here we develop a micromagnetic model based on the extended Landau-Lifshitz-Bloch equation, which is firstly validated by directly reproducing atomistic results for small samples and uniform laser heating. After that, the model is used to study ultrafast single shot all-optical switching in ferrimagnetic alloys under realistic conditions. We find that the helicity-independent switching under a linearly polarized laser pulse is a pure thermal phenomenon, in which the size of inverted area directly correlates with the maximum electron temperature in the sample. On the other hand, the analysis of the helicity-dependent processes under circular polarized pulses in ferrimagnetic alloys with different composition indicates qualitative differences between the results predicted by the magnetic circular dichroism and the ones from inverse Faraday effect. Based on these predictions, we propose experiments that would allow to resolve the controversy over the physical phenomenon that underlies these helicity-dependent all optical processes.
arXiv commentmanuscript and supplementary material, 25+19 pages, 6+10 figures
References in corpus (18)
- Atomistic spin model simulations of magnetic nanomaterials
- All-optical control of ferromagnetic thin films and nanostructures
- Two types of all-optical magnetization switching mechanisms using femtosecond laser pulses
- Ab Initio Theory of Coherent Laser-Induced Magnetization in Metals
- Single pulse all-optical toggle switching of magnetization without Gd: The example of Mn2RuxGa
- Speed limit of FePt spin dynamics on femtosecond timescales
- Comparing all-optical switching in synthetic-ferrimagnetic multilayers and alloys
- The Landau-Lifshitz-Bloch equation for ferrimagnetic materials
- Blueprint for deterministic all-optical switching of magnetization
- Gilbert damping phenomenology for two-sublattice magnets
- All-optical switching in granular ferromagnets caused by magnetic circular dichroism
- Role of Element-Specific Damping on the Ultrafast, Helicity-Independent All-Optical Switching Dynamics in Amorphous (Gd,Tb)Co Thin Films
- Manipulating magnetism by ultrafast control of the exchange interaction
- All-optical helicity-independent switching state diagram in GdFeCo alloys
- Exchange relaxation as the mechanism of ultrafast spin reorientation in two-sublattice ferrimagnets
- Ultra-fast Double Pulse All-Optical Re-switching of a Ferrimagnet
- Modeling ultrafast all-optical switching in synthetic ferrimagnets
- Stochastic ferrimagnetic Landau-Lifshitz-Bloch equation for finite magnetic structures