TY - JOUR
T1 - Femtosecond formation dynamics of the spin Seebeck effect revealed by terahertz spectroscopy
AU - Seifert, Tom S.
AU - Jaiswal, Samridh
AU - Barker, Joseph
AU - Weber, Sebastian T.
AU - Razdolski, Ilya
AU - Cramer, Joel
AU - Gueckstock, Oliver
AU - Maehrlein, Sebastian F.
AU - Nadvornik, Lukas
AU - Watanabe, Shun
AU - Ciccarelli, Chiara
AU - Melnikov, Alexey
AU - Jakob, Gerhard
AU - Münzenberg, Markus
AU - Goennenwein, Sebastian T.B.
AU - Woltersdorf, Georg
AU - Rethfeld, Baerbel
AU - Brouwer, Piet W.
AU - Wolf, Martin
AU - Kläui, Mathias
AU - Kampfrath, Tobias
N1 - Funding Information:
We thank G.E.W. Bauer for stimulating discussions and acknowledge funding by the ERC H2020 CoG project TERAMAG/Grant No. 681917, the collaborative research center SFB TRR 227 Ultrafast spin dynamics (projects B01, B02 and B03), the collaborative research center SFB TRR 173 Spin+X (projects A01, A08 and B02), the Marie Curie FP7 project ITN WALL/Grant No. 608031, the DAAD (SpinNet, MaHoJeRo) as well as the DFG priority programs SPP 1538 SpinCaT and SPP 1666 Topological Insulators.
Publisher Copyright:
© 2018, The Author(s).
PY - 2018/12/1
Y1 - 2018/12/1
N2 - 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.
AB - 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.
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U2 - 10.1038/s41467-018-05135-2
DO - 10.1038/s41467-018-05135-2
M3 - Article
C2 - 30042421
AN - SCOPUS:85050636678
SN - 2041-1723
VL - 9
JO - Nature Communications
JF - Nature Communications
IS - 1
M1 - 2899
ER -