Ultrafast spin-currents and charge conversion at 3d-5d interfaces probed by time-domain terahertz spectroscopy

Abstract

Spintronic structures are extensively investigated for their spin orbit torque properties, required for magnetic commutation functionalities. Current progress in these materials is dependent on the interface engineering for the optimization of spin transmission. Here, we advance the analysis of ultrafast spin-charge conversion phenomena at ferromagnetic-transition metal interfaces due to their inverse spin-Hall effect properties. In particular the intrinsic inverse spin Hall effect of Pt-based systems and extrinsic inverse spin-Hall effect of Au:W and Au:Ta in NiFe/Au:(W,Ta) bilayers are investigated. The spin-charge conversion is probed by complementary techniques -- ultrafast THz time domain spectroscopy in the dynamic regime for THz pulse emission and ferromagnetic resonance spin-pumping measurements in the GHz regime in the steady state -- to determine the role played by the material properties, resistivities, spin transmission at metallic interfaces and spin-flip rates. These measurements show the correspondence between the THz time domain spectroscopy and ferromagnetic spin-pumping for the different set of samples in term of the spin mixing conductance. The latter quantity is a critical parameter, determining the strength of the THz emission from spintronic interfaces. This is further supported by ab-initio calculations, simulations and analysis of the spin-diffusion and spin relaxation of carriers within the multilayers in the time domain, permitting to determine the main trends and the role of spin transmission at interfaces. This work illustrates that time domain spectroscopy for spin-based THz emission is a powerful technique to probe spin-dynamics at active spintronic interfaces and to extract key material properties for spin-charge conversion.

20 pages

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Cited by in corpus (21)

• Maximizing Spin-Orbit Torque Generated by the Spin Hall Effect of Pt
• Spintronic Sources of Ultrashort Terahertz Electromagnetic Pulses
• Principles of spintronic THz emitters
• Ultrafast THz probing of nonlocal orbital current in transverse multilayer metallic heterostructures
• Modeling ultrafast demagnetization and spin transport: the interplay of spin-polarized electrons and thermal magnons
• Ultrafast spin-charge conversion at SnBi${}_2$Te${}_4$/Co topological insulator interfaces probed by terahertz emission spectroscopy
• 360° polarization control of terahertz spintronic emitters using uniaxial FeCo/TbCo2/FeCo trilayers
• Strong Spin-Orbit Torque Induced by the Intrinsic Spin Hall Effect in Cr1-xPtx
• Spin-voltage-driven efficient terahertz spin currents from the magnetic Weyl semimetals Co${}_2$MnGa and Co${}_2$MnAl
• Spintronic THz emitters based on transition metals and semi-metals/Pt multilayers
• Light and microwave driven spin pumping across FeGaB-BiSb interface
• Impact of gigahertz and terahertz transport regimes on spin propagation and conversion in the antiferromagnet IrMn
• Element resolved evidence of superdiffusive terahertz spin current arising from ultrafast demagnetization process
• Spin to charge conversion at Rashba-split SrTiO${}_3$ interfaces from resonant tunneling
• Phonon-mediated strong coupling between a three-dimensional topological insulator and a two-dimensional antiferromagnetic material
• Inverse Rashba-Edelstein THz emission modulation induced by ferroelectricity in CoFeB/PtSe2/MoSe2//LiNbO3 systems
• Multi-band character revealed from Weak-antilocalization effect in Platinum thin films
• Spin Hall magnetoresistance in Pt/(Ga,Mn)N devices
• Spin and Orbital Rashba response in ferroelectric polarized PtSe${}_2$/MoSe${}_2$/LiNbO${}_3$ heterostructures
• Externally controlled and switchable 2D electron gas at the Rashba interface between ferroelectrics and heavy $d$ metals
• Optimizing spin-based terahertz emission from magnetic heterostructures