Femtosecond formation dynamics of the spin Seebeck effect revealed by terahertz spectroscopy.
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Authors
Seifert, Tom S
Razdolski, Ilya
Cramer, Joel
Nadvornik, Lukas
Watanabe, Shun
Melnikov, Alexey
Jakob, Gerhard
Woltersdorf, Georg
Rethfeld, Baerbel
Brouwer, Piet W
Wolf, Martin
Kampfrath, Tobias
Publication Date
2018-07-24Journal Title
Nature communications
ISSN
2041-1723
Volume
9
Issue
1
Pages
2899
Language
eng
Type
Article
This Version
AM
Physical Medium
Electronic
Metadata
Show full item recordCitation
Seifert, T. S., Jaiswal, S., Barker, J., Weber, S. T., Razdolski, I., Cramer, J., Gueckstock, O., et al. (2018). Femtosecond formation dynamics of the spin Seebeck effect revealed by terahertz spectroscopy.. Nature communications, 9 (1), 2899. https://doi.org/10.1038/s41467-018-05135-2
Abstract
Understanding the transfer of spin angular momentum is essential in modern magnetism research. A model case is the generation of magnons in magnetic insulators by heating an adjacent metal film. Here, we reveal the initial steps of this spin Seebeck effect with <27 fs time resolution using terahertz spectroscopy on bilayers of ferrimagnetic yttrium iron garnet and platinum. Upon exciting the metal with an infrared laser pulse, a spin Seebeck current js arises on the same ~100 fs time scale on which the metal electrons thermalize. This observation highlights that efficient spin transfer critically relies on carrier multiplication and is driven by conduction electrons scattering off the metal-insulator interface. Analytical modeling shows that the electrons' dynamics are almost instantaneously imprinted onto js because their spins have a correlation time of only ~4 fs and deflect the ferrimagnetic moments without inertia. Applications in material characterization, interface probing, spin-noise spectroscopy and terahertz spin pumping emerge.
Identifiers
External DOI: https://doi.org/10.1038/s41467-018-05135-2
This record's URL: https://www.repository.cam.ac.uk/handle/1810/290274