Determination of spin Hall effect and spin diffusion length of Pt from self-consistent fitting of damping enhancement and inverse spin-orbit torque measurements

Abstract

Understanding the evolution of spin-orbit torque (SOT) with increasing heavy-metal thickness in ferromagnet/normal metal (FM/NM) bilayers is critical for the development of magnetic memory based on SOT. However, several experiments have revealed an apparent discrepancy between damping enhancement and damping-like SOT regarding their dependence on NM thickness. Here, using linewidth and phase-resolved amplitude analysis of vector network analyzer ferromagnetic resonance (VNA-FMR) measurements, we simultaneously extract damping enhancement and both field-like and damping-like inverse SOT in Ni${}_{80}$Fe${}_{20}$/Pt bilayers as a function of Pt thickness. By enforcing an interpretation of the data which satisfies Onsager reciprocity, we find that both the damping enhancement and damping-like inverse SOT can be described by a single spin diffusion length ($\approx$ 4 nm), and that we can separate the spin pumping and spin memory loss (SML) contributions to the total damping. This analysis indicates that less than 40% of the angular momentum pumped by FMR through the Ni${}_{80}$Fe${}_{20}$/Pt interface is transported as spin current into the Pt. On account of the SML and corresponding reduction in total spin current available for spin-charge transduction in the Pt, we determine the Pt spin Hall conductivity (${\sigma }_{\mathrm{SH}}=(2.36\pm 0.04)\times 10^6{\Omega }^{-1}{\mathrm{m}}^{-1}$) and bulk spin Hall angle (${\theta }_{\mathrm{SH}}=0.387\pm 0.008$) to be larger than commonly-cited values. These results suggest that Pt can be an extremely useful source of SOT if the FM/NM interface can be engineered to minimize SML. Lastly, we find that self-consistent fitting of the damping and SOT data is best achieved by a model with Elliott-Yafet spin relaxation and extrinsic inverse spin Hall effect, such that both the spin diffusion length and spin Hall conductivity are proportional to the Pt charge conductivity.

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• Transport Spin Polarization of Noncollinear Antiferromagnetic Antiperovskites
• Separation of the two-magnon scattering contribution to damping for the determination of the spin mixing conductance
• Spin-orbit torque and spin pumping in YIG/Pt with interfacial insertion layers
• Temperature-dependent spin-transport and current-induced torques in superconductor/ferromagnet heterostructures
• Spin pumping and spin torque in interfacial tailored Co2FeAl/\b{eta}-Ta layers
• Near-Unity Spin Hall Ratio in Ni${}_x$Cu${}_{1-x}$ Alloys
• Spintronic THz emitters based on transition metals and semi-metals/Pt multilayers
• Mitigation of Gilbert Damping in the CoFe/CuOx Orbital Torque System
• Spin absorption at ferromagnetic-metal/platinum-oxide interface
• Unconventional anomalous Hall effect in 3d/5d multilayers mediated by the nonlocal spin-conductivity
• Anomalous Hall-like transverse magnetoresistance in Au thin films on Y${}_3$Fe${}_5$O${}_{12}$
• Charge-Spin Interconversion in Epitaxial Pt Probed by Spin-Orbit Torques in a Magnetic Insulator
• Spin transport at finite temperatures: A first-principles study for ferromagnetic$|$nonmagnetic interfaces
• Negligible thermal contributions to the spin pumping signal in ferromagnetic metal-Platinum bilayers
• Easy-plane spin Hall oscillator
• Determining complex spin mixing conductance and spin diffusion length from spin pumping experiments in magnetic insulator/heavy metal bilayers
• Stacking-order effect on spin-orbit torque, spin-Hall magnetoresistance, and magnetic anisotropy in Ni${}_{81}$Fe${}_{19}$-IrO${}_2$ bilayers
• Spin-memory loss induced by bulk spin-orbit coupling at ferromagnet/heavy-metal interfaces
• Level attraction and exceptional points in a resonant spin-orbit torque system
• Revealing the importance of interfaces for pure spin current transport
• Diffusive and Fluid-like Motion of Homochiral Domain Walls in Easy-Plane Magnetic Strips
• Sizable spin-transfer torque in Bi/Ni80Fe20 bilayer film
• Calculating interface transport parameters at finite temperatures: Nonmagnetic interfaces
• Spin transport and magnetic proximity effect in CoFeB/normal metal/Pt trilayers
• Spin-circuit representation of spin-torque ferromagnetic resonance
• Suppression of Spin Pumping at Metal Interfaces
• Intrinsic nature of the giant spin Hall conductivity of Pt
• Inductive detection of inverse spin-orbit torques in magnetic heterostructures
• Spin-orbit torque: Moving towards two-dimensional van der Waals heterostructures