Tuning ultrafast demagnetization with ultrashort spin polarized currents in multi-sublattice ferrimagnets
Abstract Femtosecond laser pulses can be used to induce ultrafast changes of the magnetization in magnetic materials. Several microscopic mechanisms have been proposed to explain these observations, including the transport of ultrashort spin-polarized hot-electrons (SPHE). However, currently such ul...
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Nature Portfolio
2025-03-01
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| Online Access: | https://doi.org/10.1038/s41467-025-58411-3 |
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| author | Deeksha Gupta Maryna Pankratova Matthias Riepp Manuel Pereiro Biplab Sanyal Soheil Ershadrad Michel Hehn Niko Pontius Christian Schüßler-Langeheine Radu Abrudan Nicolas Bergeard Anders Bergman Olle Eriksson Christine Boeglin |
| author_facet | Deeksha Gupta Maryna Pankratova Matthias Riepp Manuel Pereiro Biplab Sanyal Soheil Ershadrad Michel Hehn Niko Pontius Christian Schüßler-Langeheine Radu Abrudan Nicolas Bergeard Anders Bergman Olle Eriksson Christine Boeglin |
| author_sort | Deeksha Gupta |
| collection | DOAJ |
| description | Abstract Femtosecond laser pulses can be used to induce ultrafast changes of the magnetization in magnetic materials. Several microscopic mechanisms have been proposed to explain these observations, including the transport of ultrashort spin-polarized hot-electrons (SPHE). However, currently such ultrafast spin currents are only poorly characterized due to the measurement requirements for element and time resolution. Here, using time- and element-resolved X-ray magnetic circular dichroism alongside atomistic spin-dynamics simulations, we study the ultrafast transfer of the angular momentum from spin-polarized currents. We show 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 can be explained with two physical mechanisms; 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 effect 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. |
| format | Article |
| id | doaj-art-035ad0d40e7a46d6aab0047aa0c8477a |
| institution | DOAJ |
| issn | 2041-1723 |
| language | English |
| publishDate | 2025-03-01 |
| publisher | Nature Portfolio |
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| series | Nature Communications |
| spelling | doaj-art-035ad0d40e7a46d6aab0047aa0c8477a2025-08-20T03:07:43ZengNature PortfolioNature Communications2041-17232025-03-0116111010.1038/s41467-025-58411-3Tuning ultrafast demagnetization with ultrashort spin polarized currents in multi-sublattice ferrimagnetsDeeksha Gupta0Maryna Pankratova1Matthias Riepp2Manuel Pereiro3Biplab Sanyal4Soheil Ershadrad5Michel Hehn6Niko Pontius7Christian Schüßler-Langeheine8Radu Abrudan9Nicolas Bergeard10Anders Bergman11Olle Eriksson12Christine Boeglin13Institut de Physique et de Chimie des Matériaux de Strasbourg, UMR7504, CNRS et Université de StrasbourgDepartment of Physics and Astronomy, Uppsala UniversityInstitut de Physique et de Chimie des Matériaux de Strasbourg, UMR7504, CNRS et Université de StrasbourgDepartment of Physics and Astronomy, Uppsala UniversityDepartment of Physics and Astronomy, Uppsala UniversityDepartment of Physics and Astronomy, Uppsala UniversityUniversité de Lorraine, Institut Jean Lamour, UMR 7198 CNRSHelmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein Str. 15Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein Str. 15Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein Str. 15Institut de Physique et de Chimie des Matériaux de Strasbourg, UMR7504, CNRS et Université de StrasbourgDepartment of Physics and Astronomy, Uppsala UniversityDepartment of Physics and Astronomy, Uppsala UniversityInstitut de Physique et de Chimie des Matériaux de Strasbourg, UMR7504, CNRS et Université de StrasbourgAbstract Femtosecond laser pulses can be used to induce ultrafast changes of the magnetization in magnetic materials. Several microscopic mechanisms have been proposed to explain these observations, including the transport of ultrashort spin-polarized hot-electrons (SPHE). However, currently such ultrafast spin currents are only poorly characterized due to the measurement requirements for element and time resolution. Here, using time- and element-resolved X-ray magnetic circular dichroism alongside atomistic spin-dynamics simulations, we study the ultrafast transfer of the angular momentum from spin-polarized currents. We show 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 can be explained with two physical mechanisms; 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 effect 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.https://doi.org/10.1038/s41467-025-58411-3 |
| spellingShingle | Deeksha Gupta Maryna Pankratova Matthias Riepp Manuel Pereiro Biplab Sanyal Soheil Ershadrad Michel Hehn Niko Pontius Christian Schüßler-Langeheine Radu Abrudan Nicolas Bergeard Anders Bergman Olle Eriksson Christine Boeglin Tuning ultrafast demagnetization with ultrashort spin polarized currents in multi-sublattice ferrimagnets Nature Communications |
| title | Tuning ultrafast demagnetization with ultrashort spin polarized currents in multi-sublattice ferrimagnets |
| title_full | Tuning ultrafast demagnetization with ultrashort spin polarized currents in multi-sublattice ferrimagnets |
| title_fullStr | Tuning ultrafast demagnetization with ultrashort spin polarized currents in multi-sublattice ferrimagnets |
| title_full_unstemmed | Tuning ultrafast demagnetization with ultrashort spin polarized currents in multi-sublattice ferrimagnets |
| title_short | Tuning ultrafast demagnetization with ultrashort spin polarized currents in multi-sublattice ferrimagnets |
| title_sort | tuning ultrafast demagnetization with ultrashort spin polarized currents in multi sublattice ferrimagnets |
| url | https://doi.org/10.1038/s41467-025-58411-3 |
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