Giant spin torque efficiency in naturally oxidized polycrystalline TaAs thin films

Abstract

We report the measurement of efficient charge-to-spin conversion at room temperature in Weyl semimetal/ferromagnet heterostructures with both oxidized and pristine interfaces. Polycrystalline films of the Weyl semimetal, TaAs, are grown by molecular beam epitaxy on (001) GaAs and interfaced with a metallic ferromagnet (Ni${}_{0.8}$Fe${}_{0.2}$). Spin torque ferromagnetic resonance (ST-FMR) measurements in samples with an oxidized interface yield a spin torque efficiency as large as ${\xi }_{\mathrm{FMR}}=0.45\pm 0.25$ for a 8 nm Ni${}_{0.8}$Fe${}_{0.2}$ layer thickness. By studying ST-FMR in these samples with varying Ni${}_{0.8}$Fe${}_{0.2}$ layer thickness, we extract a damping-like torque efficiency as high as ${\xi }_{\mathrm{DL}}=1.36\pm 0.66$. In samples with a pristine (unoxidized) interface, the spin torque efficiency has opposite sign to that observed in oxidized samples (${\xi }_{\mathrm{FMR}}=-0.27\pm 0.14$ for a 5 nm Ni${}_{0.8}$Fe${}_{0.2}$ layer thickness). We also find a lower bound on the spin Hall conductivity ($424\pm 110\frac{\hslash }{e}$ S/cm) which is surprisingly consistent with theoretical predictions for the single crystal Weyl semimetal state of TaAs.

References in corpus (25)

• Spin torque switching with the giant spin Hall effect of tantalum
• Discovery of a Weyl Fermion Semimetal and Topological Fermi Arcs
• Spin Torque Ferromagnetic Resonance Induced by the Spin Hall Effect
• Observation of the chiral anomaly induced negative magneto-resistance in 3D Weyl semi-metal TaAs
• Spin Transfer Torque Generated by the Topological Insulator Bi_2Se_3
• Control of spin-orbit torques through crystal symmetry in WTe2/ferromagnet bilayers
• Study of Intrinsic Spin Hall Effect and Orbital Hall Effect in 4d- and 5d- Transition Metals
• Dependence of the Efficiency of Spin Hall Torque on the Transparency of Pt-Ferromagnetic Layer Interfaces
• Room-temperature perpendicular magnetization switching through giant spin-orbit torque from sputtered BixSe(1-x) topological insulator material
• Fermi level dependent charge-to-spin current conversion by Dirac surface state of topological insulators
• Room temperature magnetization switching in topological insulator-ferromagnet heterostructures by spin-orbit torques
• Giant intrinsic spin Hall effect in the TaAs family of Weyl semimetals
• Surface state dominated spin-charge current conversion in topological insulator/ferromagnetic insulator heterostructures
• Thickness dependence of spin-orbit torques generated by WTe2
• Orbital Rashba effect in surface oxidized Cu film
• On the origin of field-like spin-orbit torques in heavy metal-ferromagnet-oxide thin film heterostructures
• Spin polarization and texture of the Fermi arcs in the Weyl Fermion semimetal TaAs
• Transverse and Longitudinal Spin-Torque Ferromagnetic Resonance for Improved Measurements of Spin-Orbit Torques
• Towards Weyltronics: Realization of epitaxial NbP and TaP Weyl Semimetal thin films
• Role of Dirac nodal lines and strain on the high spin Hall conductivity of epitaxial IrO2 thin films
• Clear variation of spin splitting by changing electron distribution at non-magnetic metal/Bi2O3 interfaces
• Fermi Level Dependent Spin Pumping from a Magnetic Insulator into a Topological Insulator
• Efficient intrinsic spin-to-charge current conversion in an all-epitaxial single-crystal perovskite-oxide heterostructure of La0.67Sr0.33MnO3/LaAlO3/SrTiO3
• Spin and charge interconversion in Dirac semimetal thin films
• Separation of Artifacts from Spin-Torque Ferromagnetic Resonance Measurements of Spin-Orbit Torque for the Low-Symmetry van der Waals Semi-Metal ZrTe${}_{\text{3}}$

Cited by in corpus (5)

• Epitaxial growth and characterization of Bi${}_{1-x}$Sb${}_x$ thin films on (0001) sapphire substrates
• Thin film growth of the Weyl semimetal NbAs
• Exploration of growth conditions of TaAs Weyl semimetal thin film by pulsed laser deposition
• Spin Hall conductivity in Bi${}_{1-x}$Sb${}_x$ as an experimental test of bulk-boundary correspondence
• Uniting Weyl semimetals and semiconductors in a family of arsenides