Non-thermal electrons open the non-equilibrium pathway of the phase transition in FeRh
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arXiv
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| Autori principali: | , , , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2023
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| _version_ | 1866908330056744960 |
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| author | Mattern, Maximilian Zeuschner, Steffen Peer Rössle, Matthias Arregi, Jon Ander Uhlíř, Vojtěch Bargheer, Matias |
| author_facet | Mattern, Maximilian Zeuschner, Steffen Peer Rössle, Matthias Arregi, Jon Ander Uhlíř, Vojtěch Bargheer, Matias |
| contents | We use ultrafast x-ray diffraction to study non-equilibrium pathways of the phase transition in FeRh parametrized by the structural response. By increasing the pump-pulse duration beyond the electron-phonon coupling time, we suppress the electron-phonon non-equilibrium present upon femtosecond laser excitation but still photoexcite electrons to non-thermal states. Irrespective of the pump pulse duration, we find an optically induced nucleation of ferromagnetic domains on an $8\,\text{ps}$ timescale that starts as soon as the successively deposited energy surpasses the site-specific threshold energy. If in contrast, FeRh is only indirectly excited by diffusion of thermalized electrons from an opaque Pt cap layer, the ferromagnetic phase rises on a $50\,\text{ps}$ timescale. These findings unambiguously identify the photo-excitation of non-thermal electrons and not electron-phonon non-equilibria to enable the non-equilibrium pathway of the phase transition in FeRh. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2310_18289 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Non-thermal electrons open the non-equilibrium pathway of the phase transition in FeRh Mattern, Maximilian Zeuschner, Steffen Peer Rössle, Matthias Arregi, Jon Ander Uhlíř, Vojtěch Bargheer, Matias Materials Science We use ultrafast x-ray diffraction to study non-equilibrium pathways of the phase transition in FeRh parametrized by the structural response. By increasing the pump-pulse duration beyond the electron-phonon coupling time, we suppress the electron-phonon non-equilibrium present upon femtosecond laser excitation but still photoexcite electrons to non-thermal states. Irrespective of the pump pulse duration, we find an optically induced nucleation of ferromagnetic domains on an $8\,\text{ps}$ timescale that starts as soon as the successively deposited energy surpasses the site-specific threshold energy. If in contrast, FeRh is only indirectly excited by diffusion of thermalized electrons from an opaque Pt cap layer, the ferromagnetic phase rises on a $50\,\text{ps}$ timescale. These findings unambiguously identify the photo-excitation of non-thermal electrons and not electron-phonon non-equilibria to enable the non-equilibrium pathway of the phase transition in FeRh. |
| title | Non-thermal electrons open the non-equilibrium pathway of the phase transition in FeRh |
| topic | Materials Science |
| url | https://arxiv.org/abs/2310.18289 |