6533b872fe1ef96bd12d43e8
RESEARCH PRODUCT
Femtosecond formation dynamics of the spin Seebeck effect revealed by terahertz spectroscopy
Gerhard JakobSamridh JaiswalSamridh JaiswalBaerbel RethfeldSebastian T. WeberPiet W. BrouwerMartin WolfAlexey MelnikovAlexey MelnikovSebastian F. MaehrleinGeorg WoltersdorfJoel CramerMathias KläuiIlya RazdolskiMarkus MünzenbergShun WatanabeJoseph BarkerChiara CiccarelliTobias KampfrathTobias KampfrathSebastian T. B. GoennenweinLukas NadvornikLukas NadvornikTom SeifertTom SeifertOliver Gueckstocksubject
MagnetismTerahertz radiation0299 Other Physical SciencesScienceGeneral Physics and AstronomyFOS: Physical sciencesPhysics::Optics02 engineering and technology01 natural sciencesGeneral Biochemistry Genetics and Molecular BiologyArticleCondensed Matter::Materials ScienceFerrimagnetism5370103 physical sciencesMesoscale and Nanoscale Physics (cond-mat.mes-hall)ddc:530010306 general physicsSpin (physics)lcsh:ScienceTerahertz opticsPhysicsSpin pumpingCondensed Matter - Materials ScienceMultidisciplinaryCondensed matter physicsCondensed Matter - Mesoscale and Nanoscale PhysicsMagnonFar-infrared laserQMaterials Science (cond-mat.mtrl-sci)General ChemistrySpintronics021001 nanoscience & nanotechnology3. Good healthTerahertz spectroscopy and technologylcsh:QCondensed Matter::Strongly Correlated Electrons0210 nano-technologydescription
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 <27fs 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 $j_\textrm{s}$ arises on the same ~100fs 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 $j_\textrm{s}$ because their spins have a correlation time of only ~4fs and deflect the ferrimagnetic moments without inertia. Applications in material characterization, interface probing, spin-noise spectroscopy and terahertz spin pumping emerge.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2018-07-24 |