Ultrafast Measurements of the Interfacial Spin Seebeck Effect in Au and Rare-Earth Iron Garnet Bilayers

Abstract

We investigate picosecond spin-currents across Au/iron-garnet interfaces in response to ultrafast laser heating of the electrons in the Au film. In the picoseconds after optical heating, interfacial spin currents occur due to an interfacial temperature difference between electrons in the metal and magnons in the insulator. We report measurements of this interfacial longitudinal spin Seebeck effect between Au and rare-earth iron-garnet insulators, i.e. RE${}_3$ Fe${}_5$O${}_{12}$, where RE is Y, Eu, Tb, Tm. We use time domain thermoreflectance (TDTR) measurements to characterize the thermal response of the bilayer to ultrafast optical heating. We use time-resolved magneto-optic Kerr effect (TR-MOKE) measurements of the Au layer to measure the time-evolution of spin accumulation in the Au film. We observe a spin Seebeck effect between Au/TmIG that is three times larger than for an Au/YIG bilayer. The interfacial thermal conductance between electrons in the Au and magnons in the TmIG layer is ~ 3 $\frac{MW}{m^{2}K}$.

References in corpus (4)

• Temperature dependence of spin diffusion length and spin Hall angle in Au and Pt
• Quantitative Temperature Dependence of Longitudinal Spin Seebeck Effect at High Temperatures
• Picosecond spin Seebeck effect
• Systematic Control of Strain-Induced Perpendicular Magnetic Anisotropy in Epitaxial Europium and Terbium Iron Garnets Thin Films

Cited by in corpus (3)

• Spin Seebeck Effect: Sensitive Probe for Elementary Excitation, Spin Correlation, Transport, Magnetic Order, and Domains in Solids
• First and second order magnetic anisotropy and damping of europium iron garnet under high strain
• Magneto-optical Kerr spectra of gold induced by spin accumulation