Ultrafast negative thermal expansion driven by spin disorder
- We measure the transient strain profile in a nanoscale multilayer system composed of yttrium, holmium, and niobium after laser excitation using ultrafast x-ray diffraction. The strain propagation through each layer is determined by transient changes in the material-specific Bragg angles. We experimentally derive the exponentially decreasing stress profile driving the strain wave and show that it closely matches the optical penetration depth. Below the Neel temperature of Ho, the optical excitation triggers negative thermal expansion, which is induced by a quasi-instantaneous contractive stress and a second contractive stress contribution increasing on a 12-ps timescale. These two timescales were recently measured for the spin disordering in Ho [Rettig et al., Phys. Rev. Lett. 116, 257202 (2016)]. As a consequence, we observe an unconventional bipolar strain pulse with an inverted sign traveling through the heterostructure.
Author details: | Jan-Etienne PudellORCiDGND, Alexander von ReppertORCiDGND, D. Schick, F. Zamponi, Matthias RössleGND, Marc HerzogORCiDGND, Hartmut ZabelGND, Matias BargheerORCiDGND |
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DOI: | https://doi.org/10.1103/PhysRevB.99.094304 |
ISSN: | 2469-9950 |
ISSN: | 2469-9969 |
Title of parent work (English): | Physical review : B, Condensed matter and materials physics |
Publisher: | American Physical Society |
Place of publishing: | College Park |
Publication type: | Article |
Language: | English |
Year of first publication: | 2019 |
Publication year: | 2019 |
Release date: | 2021/03/17 |
Volume: | 99 |
Issue: | 9 |
Number of pages: | 7 |
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 / Green Open-Access |