Femtosecond formation dynamics of the spin Seebeck effect revealed by terahertz spectroscopy

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 <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 $j_{\text{s}}$ 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 $j_{\text{s}}$ 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.

14 pages, 5 figures

References in corpus (38)

• Shot Noise in Mesoscopic Conductors
• Spin Transfer Torques
• Spin Caloritronics
• Nonlocal magnetization dynamics in ferromagnetic heterostructures
• Spin Seebeck insulator
• Efficient metallic spintronic emitters of ultrabroadband terahertz radiation
• Anatomy of Spin-Transfer Torque
• Theory of magnon-driven spin Seebeck effect
• Theory of the Spin Seebeck Effect
• Longitudinal Spin Seebeck Effect Free from the Proximity Nernst Effect
• Experimental test of the spin mixing interface conductivity concept
• Ultrafast photocurrents at the surface of the three-dimensional topological insulator ${\mathrm{Bi}}_2{\mathrm{Se}}_3$
• Evolution of the spin Hall effect in Pt nanowires: Size and temperature effects
• Spin transfer torque on magnetic insulators
• Powerful and Tunable THz Emitters Based on the Fe/Pt Magnetic Heterostructure
• Ultrabroadband single-cycle terahertz pulses with peak fields of 300 kV cm${}^{-1}$ from a metallic spintronic emitter
• Determination of the origin of the spin Seebeck effect - bulk vs. interface effects
• Optimized Spintronic Terahertz Emitters Based on Epitaxial Grown Fe/Pt Layer Structures
• Thermal spin dynamics of yttrium iron garnet
• Nanoscale confinement of ultrafast spin transfer torque exciting non-uniform spin dynamics by femtosecond spin current pulses
• Inverse Spin Hall Effect in NiFe / Normal Metal Bilayers
• Gilbert Damping in Magnetic Multilayers
• Investigation of induced Pt magnetic polarization in Pt/Y3Fe5O12 bilayers
• Macrospin Dynamics in Antiferromagnets Triggered by Sub-20 femtosecond Injection of Nanomagnons
• Quantitative Temperature Dependence of Longitudinal Spin Seebeck Effect at High Temperatures
• Picosecond spin Seebeck effect
• Enhancement of Pure Spin Currents in Spin Pumping Y3Fe5O12/Cu/metal Trilayers through Spin Conductance Matching
• Electron-Magnon Scattering in Magnetic Heterostructures Far Out-of-Equilibrium
• Competing effects at Pt/YIG interfaces: spin Hall magnetoresistance, magnon excitations and magnetic frustration
• The Landau-Lifshitz equation in atomistic models
• Sub-microsecond fast temporal evolution of the spin Seebeck effect
• Complex THz and DC inverse spin Hall effect in YIG/Cu${}_{1-x}$Ir${}_x$ bilayers across a wide concentration range
• Intrinsic and extrinsic contributions to spin scattering in Pt
• Fokker-Planck approach to the theory of magnon-driven spin Seebeck effect
• Spin Seebeck effect at microwave frequencies
• Spin wave excitations: The main source of the temperature dependence of Interlayer exchange coupling in nanostructures
• Signal propagation in time-dependent spin transport
• Imaging Magnetization Structure and Dynamics in Ultrathin YIG/Pt Bilayers with High Sensitivity Using the Time-Resolved Longitudinal Spin Seebeck Effect

Cited by in corpus (50)

• Time-domain observation of ballistic orbital-angular-momentum currents with giant relaxation length in tungsten
• Spintronic Sources of Ultrashort Terahertz Electromagnetic Pulses
• Low damping and microstructural perfection of sub-40nm-thin yttrium iron garnet films grown by liquid phase epitaxy
• Terahertz spectroscopy for all-optical spintronic characterization of the spin-Hall-effect metals Pt, W and Cu${}_{80}$Ir${}_{20}$
• Principles of spintronic THz emitters
• Phase-resolved Detection of Ultrabroadband THz Pulses inside a Scanning Tunneling Microscope Junction
• Spin Seebeck effect in the layered ferromagnetic insulators CrSiTe${}_3$ and CrGeTe${}_3$
• Terahertz emission from anomalous Hall effect in a single-layer ferromagnet
• Modification of spintronic terahertz emitter performance through defect engineering
• Spin and spin current -- From fundamentals to recent progress
• Spin Seebeck Effect: Sensitive Probe for Elementary Excitation, Spin Correlation, Transport, Magnetic Order, and Domains in Solids
• A review of modelling in ferrimagnetic spintronics
• Parametric dependence of hot electron relaxation timescales on electron-electron and electron-phonon interaction strengths
• Modeling ultrafast demagnetization and spin transport: the interplay of spin-polarized electrons and thermal magnons
• Frequency-independent terahertz anomalous Hall effect in DyCo${}_5$, Co${}_{32}$Fe${}_{68}$ and Gd${}_{27}$Fe${}_{73}$ thin films from DC to 40 THz
• Boltzmann approach to the longitudinal spin Seebeck effect
• Transition of laser-induced terahertz spin currents from torque- to conduction-electron-mediated transport
• Spin-voltage-driven efficient terahertz spin currents from the magnetic Weyl semimetals Co${}_2$MnGa and Co${}_2$MnAl
• Ultrafast photocurrents in MoSe${}_2$ probed by terahertz spectroscopy
• Generation of third-harmonic spin oscillation from strong spin precession induced by terahertz magnetic near fields
• Theory for shift current of bosons: Photogalvanic spin current in ferrimagnetic and antiferromagnetic insulators
• Dynamical properties of a driven dissipative dimerized $S=1/2$ chain
• The importance of the interface for picosecond spin pumping in antiferromagnet-heavy metal heterostructures
• Spin pumping at terahertz nutation resonances
• Temperature dependence of the interface spin Seebeck effect
• Impact of gigahertz and terahertz transport regimes on spin propagation and conversion in the antiferromagnet IrMn
• Nonrelativistic and nonmagnetic control of terahertz charge currents via electrical anisotropy in RuO2 and IrO2
• Accessing ultrafast spin-transport dynamics in copper using broadband terahertz spectroscopy
• Terahertz response of gadolinium gallium garnet (GGG) and gadolinium scandium gallium garnet (SGGG)
• Theory of spin-Hall magnetoresistance in the AC (terahertz) regime
• Thermal effects in spintronic materials and devices: an experimentalist's guide
• Ultrafast Measurements of the Interfacial Spin Seebeck Effect in Au and Rare-Earth Iron Garnet Bilayers
• Microwave control of thermal magnon spin transport
• Giant localised spin-Peltier effect due to ultrafast domainwalls motion in antiferromagnetic metals
• Spin-polarized hot electron transport versus spin pumping mediated by local heating
• Magnetoresistive detection of perpendicular switching in a magnetic insulator
• Ultrafast transport and relaxation of hot plasmonic electrons in metal-dielectric heterostructures
• Direct optical probing of ultrafast spin dynamics in a magnetic semiconductor
• Reduced effective magnetization and damping by slowly-relaxing impurities in strained $\gamma$-$\mathrm{F}{\mathrm{e}}_2{\mathrm{O}}_3$ thin films
• Spin Peltier effect and its length scale in Pt/YIG system at high temperatures
• Finite-frequency spin conductance of a ferro-/ferrimagnetic-insulator|normal-metal interface
• Ultrafast relaxation dynamics of excited carriers in metals: Simplifying the intertwined dependencies upon scattering strengths, phonon temperature, photon energy, and excitation level
• Stratonovich-Ito integration scheme in ultrafast spin caloritronics
• Terahertz time-domain signatures of the inverse Edelstein effect in topological-insulator|ferromagnet heterostructures
• Unidirectional exceptional point of reflectionless states in a magnonic mirror array
• Emergent spin Hall conductivity in Tantalum-Rhenium alloys
• Magnon-mediated electric current drag and nonlocal spin-Peltier effect in the ac regime
• Ultrafast lattice dynamics and electron-phonon coupling in platinum extracted with a global fitting approach for time-resolved polycrystalline diffraction data
• Alternating Spintronics: Capacitive Behavior of Spin Valves and Resonator Applications
• Differentiating Contributions of Electrons and Phonons to the Thermoreflectance Spectra of Gold