Ultrafast laser generated strain in granular and continuous FePt thin films
- We employ ultrafast X-ray diffraction to compare the lattice dynamics of laser-excited continuous and granular FePt films on MgO (100) substrates. Contrary to recent results on free-standing granular films, we observe in both cases a pronounced and long-lasting out-of-plane expansion. We attribute this discrepancy to the in-plane expansion, which is suppressed by symmetry in continuous films. Granular films on substrates are less constrained and already show a reduced out-of-plane contraction. Via the Poisson effect, out-of-plane contractions drive in-plane expansion and vice versa. Consistently, the granular film exhibits a short-lived out-of-plane contraction driven by ultrafast demagnetization which is followed by a reduced and delayed expansion. From the acoustic reflections of the observed strain waves at the film-substrate interface, we extract a 13% reduction of the elastic constants in thin 10 nm FePt films compared to bulk-like samples. (C) 2018 Author(s).
Author details: | Alexander von ReppertORCiDGND, Lisa WilligORCiDGND, Jan-Etienne PudellORCiDGND, M. Roessle, Wolfram LeitenbergerGND, Marc HerzogORCiDGND, F. Ganss, O. Hellwig, Matias BargheerORCiDGND |
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DOI: | https://doi.org/10.1063/1.5050234 |
ISSN: | 0003-6951 |
ISSN: | 1077-3118 |
Title of parent work (English): | Applied physics letters |
Publisher: | American Institute of Physics |
Place of publishing: | Melville |
Publication type: | Article |
Language: | English |
Year of first publication: | 2018 |
Publication year: | 2018 |
Release date: | 2021/09/27 |
Volume: | 113 |
Issue: | 12 |
Number of pages: | 5 |
Funding institution: | BMBFFederal Ministry of Education & Research (BMBF) [05K16IPA]; DFGGerman Research Foundation (DFG) [BA 2281/8-1, BA 2281/11-1] |
Organizational units: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Physik und Astronomie |
DDC classification: | 5 Naturwissenschaften und Mathematik / 53 Physik / 530 Physik |
Peer review: | Referiert |
Publishing method: | Open Access / Hybrid Open-Access |
License (German): | CC-BY - Namensnennung 4.0 International |