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Unconventional picosecond strain pulses resulting from the saturation of magnetic stress within a photoexcited rare earth layer
Optical excitation of spin-ordered rare earth metals triggers a complex response of the crystal lattice since expansive stresses from electron and phonon excitations compete with a contractive stress induced by spin disorder. Using ultrafast x-ray diffraction experiments, we study the layer specific...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Crystallographic Association
2020
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7101248/ https://www.ncbi.nlm.nih.gov/pubmed/32232076 http://dx.doi.org/10.1063/1.5145315 |
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author | von Reppert, A. Mattern, M. Pudell, J.-E. Zeuschner, S. P. Dumesnil, K. Bargheer, M. |
author_facet | von Reppert, A. Mattern, M. Pudell, J.-E. Zeuschner, S. P. Dumesnil, K. Bargheer, M. |
author_sort | von Reppert, A. |
collection | PubMed |
description | Optical excitation of spin-ordered rare earth metals triggers a complex response of the crystal lattice since expansive stresses from electron and phonon excitations compete with a contractive stress induced by spin disorder. Using ultrafast x-ray diffraction experiments, we study the layer specific strain response of a dysprosium film within a metallic heterostructure upon femtosecond laser-excitation. The elastic and diffusive transport of energy to an adjacent, non-excited detection layer clearly separates the contributions of strain pulses and thermal excitations in the time domain. We find that energy transfer processes to magnetic excitations significantly modify the observed conventional bipolar strain wave into a unipolar pulse. By modeling the spin system as a saturable energy reservoir that generates substantial contractive stress on ultrafast timescales, we can reproduce the observed strain response and estimate the time- and space dependent magnetic stress. The saturation of the magnetic stress contribution yields a non-monotonous total stress within the nanolayer, which leads to unconventional picosecond strain pulses. |
format | Online Article Text |
id | pubmed-7101248 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
publisher | American Crystallographic Association |
record_format | MEDLINE/PubMed |
spelling | pubmed-71012482020-03-30 Unconventional picosecond strain pulses resulting from the saturation of magnetic stress within a photoexcited rare earth layer von Reppert, A. Mattern, M. Pudell, J.-E. Zeuschner, S. P. Dumesnil, K. Bargheer, M. Struct Dyn ARTICLES Optical excitation of spin-ordered rare earth metals triggers a complex response of the crystal lattice since expansive stresses from electron and phonon excitations compete with a contractive stress induced by spin disorder. Using ultrafast x-ray diffraction experiments, we study the layer specific strain response of a dysprosium film within a metallic heterostructure upon femtosecond laser-excitation. The elastic and diffusive transport of energy to an adjacent, non-excited detection layer clearly separates the contributions of strain pulses and thermal excitations in the time domain. We find that energy transfer processes to magnetic excitations significantly modify the observed conventional bipolar strain wave into a unipolar pulse. By modeling the spin system as a saturable energy reservoir that generates substantial contractive stress on ultrafast timescales, we can reproduce the observed strain response and estimate the time- and space dependent magnetic stress. The saturation of the magnetic stress contribution yields a non-monotonous total stress within the nanolayer, which leads to unconventional picosecond strain pulses. American Crystallographic Association 2020-03-27 /pmc/articles/PMC7101248/ /pubmed/32232076 http://dx.doi.org/10.1063/1.5145315 Text en © 2020 Author(s). 2329-7778/2020/7(2)/024303/12 All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). |
spellingShingle | ARTICLES von Reppert, A. Mattern, M. Pudell, J.-E. Zeuschner, S. P. Dumesnil, K. Bargheer, M. Unconventional picosecond strain pulses resulting from the saturation of magnetic stress within a photoexcited rare earth layer |
title | Unconventional picosecond strain pulses resulting from the saturation of magnetic stress within a photoexcited rare earth layer |
title_full | Unconventional picosecond strain pulses resulting from the saturation of magnetic stress within a photoexcited rare earth layer |
title_fullStr | Unconventional picosecond strain pulses resulting from the saturation of magnetic stress within a photoexcited rare earth layer |
title_full_unstemmed | Unconventional picosecond strain pulses resulting from the saturation of magnetic stress within a photoexcited rare earth layer |
title_short | Unconventional picosecond strain pulses resulting from the saturation of magnetic stress within a photoexcited rare earth layer |
title_sort | unconventional picosecond strain pulses resulting from the saturation of magnetic stress within a photoexcited rare earth layer |
topic | ARTICLES |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7101248/ https://www.ncbi.nlm.nih.gov/pubmed/32232076 http://dx.doi.org/10.1063/1.5145315 |
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