Tuning of the ultrafast demagnetization by ultrashort spin polarized currents in multi-sublattice ferrimagnets
Fuente:
arXiv
Saved in:
| Main Authors: | , , , , , , , , , , , , , |
|---|---|
| Format: | Preprint |
| Published: |
2024
|
| Subjects: | |
| Online Access: | |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1866910733873184768 |
|---|---|
| author | Gupta, Deeksha Pankratova, Maryna Riepp, Matthias Pereiro, Manuel Sanyal, Biplab Ershadrad, Soheil Hehn, Michel Pontius, Niko Schüßler-Langeheine, Christian Abrudan, Radu Bergeard, Nicolas Bergman, Anders Eriksson, Olle Boeglin, Christine |
| author_facet | Gupta, Deeksha Pankratova, Maryna Riepp, Matthias Pereiro, Manuel Sanyal, Biplab Ershadrad, Soheil Hehn, Michel Pontius, Niko Schüßler-Langeheine, Christian Abrudan, Radu Bergeard, Nicolas Bergman, Anders Eriksson, Olle Boeglin, Christine |
| contents | Femtosecond laser pulses can be used to induce ultrafast changes of the magnetization in magnetic materials. Several microscopic mechanisms have been proposed to explain the observations, including the transport of ultrashort spin-polarized hot-electrons (SPHE). Such ultrafast spin currents find growing interest because of the recent challenges in ultrafast spintronics however they are only poorly characterized. One of the key challenges is to characterize the spin-polarized ultrafast currents and the microscopic mechanisms behind SPHE induced manipulation of the magnetization, especially in the case of technologically relevant ferrimagnetic alloys. Here, we have used a combined approach using time- and element-resolved X-ray magnetic circular dichroism and theoretical calculations based on atomistic spin-dynamics simulations to address the ultrafast transfer of the angular momentum from spin-polarized currents into ferrimagnetic Fe74Gd26 films and the concomitant reduction of sub-lattice magnetization. Our study shows that using a Co/Pt multilayer as a polarizer in a spin-valve structure, the SPHE drives the demagnetization of the two sub-lattices of the Fe74Gd26 film. This behaviour is explained based on two physical mechanisms, i.e., spin transfer torque and thermal fluctuations induced by the SPHE. We provide a quantitative description of the heat transfer of the ultrashort SPHE pulse to the Fe74Gd26 films, as well as the degree of spin-polarization of the SPHE current density responsible for the observed magnetization dynamics. Our work finally characterizes the spin-polarization of the SPHEs revealing unexpected opposite spin polarization to the Co magnetization, explaining our experimental results. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2403_11739 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Tuning of the ultrafast demagnetization by ultrashort spin polarized currents in multi-sublattice ferrimagnets Gupta, Deeksha Pankratova, Maryna Riepp, Matthias Pereiro, Manuel Sanyal, Biplab Ershadrad, Soheil Hehn, Michel Pontius, Niko Schüßler-Langeheine, Christian Abrudan, Radu Bergeard, Nicolas Bergman, Anders Eriksson, Olle Boeglin, Christine Materials Science Femtosecond laser pulses can be used to induce ultrafast changes of the magnetization in magnetic materials. Several microscopic mechanisms have been proposed to explain the observations, including the transport of ultrashort spin-polarized hot-electrons (SPHE). Such ultrafast spin currents find growing interest because of the recent challenges in ultrafast spintronics however they are only poorly characterized. One of the key challenges is to characterize the spin-polarized ultrafast currents and the microscopic mechanisms behind SPHE induced manipulation of the magnetization, especially in the case of technologically relevant ferrimagnetic alloys. Here, we have used a combined approach using time- and element-resolved X-ray magnetic circular dichroism and theoretical calculations based on atomistic spin-dynamics simulations to address the ultrafast transfer of the angular momentum from spin-polarized currents into ferrimagnetic Fe74Gd26 films and the concomitant reduction of sub-lattice magnetization. Our study shows that using a Co/Pt multilayer as a polarizer in a spin-valve structure, the SPHE drives the demagnetization of the two sub-lattices of the Fe74Gd26 film. This behaviour is explained based on two physical mechanisms, i.e., spin transfer torque and thermal fluctuations induced by the SPHE. We provide a quantitative description of the heat transfer of the ultrashort SPHE pulse to the Fe74Gd26 films, as well as the degree of spin-polarization of the SPHE current density responsible for the observed magnetization dynamics. Our work finally characterizes the spin-polarization of the SPHEs revealing unexpected opposite spin polarization to the Co magnetization, explaining our experimental results. |
| title | Tuning of the ultrafast demagnetization by ultrashort spin polarized currents in multi-sublattice ferrimagnets |
| topic | Materials Science |
| url | https://arxiv.org/abs/2403.11739 |