Spin wave emission by spin-orbit torque antennas

Abstract

We study the generation of propagating spin waves in Ta/CoFeB waveguides by spin-orbit torque antennas and compare them to conventional inductive antennas. The spin-orbit torque was generated by a transverse microwave current across the magnetic waveguide. The detected spin wave signals for an in-plane magnetization across the waveguide (Damon-Eshbach configuration) exhibited the expected phase rotation and amplitude decay upon propagation when the current spreading was taken into account. Wavevectors up to about 6 rad/$\mu$m could be excited by the spin-orbit torque antennas despite the current spreading, presumably due to the non-uniformity of the microwave current. The relative magnitude of generated anti-damping spin-Hall and Oersted fields was calculated within an analytic model and it was found that they contribute approximately equally to the total effective field generated by the spin-orbit torque antenna. Due to the ellipticity of the precession in the ultrathin waveguide and the different orientation of the anti-damping spin-Hall and Oersted fields, the torque was however still dominated by the Oersted field. The prospects for obtaining a pure spin-orbit torque response are discussed, as are the energy efficiency and the scaling properties of spin-orbit torque antennas.

arXiv comment20 pages, 5 figures

References in corpus (17)

• Spin torque switching with the giant spin Hall effect of tantalum
• Spin Transfer Torque Generated by the Topological Insulator Bi_2Se_3
• Spin transfer torque devices utilizing the giant spin Hall effect of tungsten
• Symmetry and magnitude of spin-orbit torques in ferromagnetic heterostructures
• Switching of perpendicular magnetization by spin-orbit torques in the absence of external magnetic fields
• Quantitative characterization of the spin orbit torque using harmonic Hall voltage measurements
• Interplay of spin-orbit torque and thermoelectric effects in ferromagnet/normal metal bilayers
• Time- and spatially-resolved magnetization dynamics driven by spin-orbit torques
• Generation of coherent spin-wave modes in Yttrium Iron Garnet microdiscs by spin-orbit torque
• Experimental prototype of a spin-wave majority gate
• Non-Volatile Magnonic Logic Circuits Engineering
• Design of a spin-wave majority gate employing mode selection
• Experimental Demonstration of the Co-existence of the Spin Hall and Rashba Effects in beta-Tantalum/Ferromagnet Bilayers
• All electrical propagating spin wave spectroscopy with broadband wavevector capability
• Spin wave dynamics and the determination of intrinsic Gilbert damping in locally-excited Permalloy thin films
• Spin wave amplification using the spin Hall effect in permalloy/platinum bilayers
• Micromagnetic simulations of magnetoelastic spin wave excitation in scaled magnetic waveguides

Cited by in corpus (12)

• Roadmap on Spin-Wave Computing
• An Introduction to Spin Wave Computing
• Reconfigurable sub-micron spin-wave majority gate with electrical transducers
• Fan-out enabled spin wave majority gate
• Experimental Realization of a Passive GHz Frequency-Division Demultiplexer for Magnonic Logic Networks
• Real-time Hall-effect detection of current-induced magnetization dynamics in ferrimagnets
• Non-reciprocity of spin waves in magnetic nanotubes with helical equilibrium magnetization
• Backward volume vs Damon-Eshbach: a travelling spin wave spectroscopy comparison
• Electrical spectroscopy of forward volume spin waves in perpendicularly magnetized materials
• Excitation and propagation of spin waves in non-uniformly magnetized waveguides
• Propagating magnetic droplet solitons as moveable nanoscale spin-wave sources with tunable direction of emission
• Correlation between structural and magnetic properties of epitaxial YIG films by pulsed laser deposition