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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...

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Detalles Bibliográficos
Autores principales: von Reppert, A., Mattern, M., Pudell, J.-E., Zeuschner, S. P., Dumesnil, K., Bargheer, M.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Crystallographic Association 2020
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.
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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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