scholarly journals Orbital torque in magnetic bilayers

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Dongjoon Lee ◽  
Dongwook Go ◽  
Hyeon-Jong Park ◽  
Wonmin Jeong ◽  
Hye-Won Ko ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Hall Effect ◽  
Spin Current ◽  
Spin Hall Effect ◽  
Spin Orbit ◽  
Magnetic Torque ◽  
Device Applications ◽  
Metal Bilayers ◽  
Experiment Analysis ◽  
Theory And Experiment

AbstractThe orbital Hall effect describes the generation of the orbital current flowing in a perpendicular direction to an external electric field, analogous to the spin Hall effect. As the orbital current carries the angular momentum as the spin current does, injection of the orbital current into a ferromagnet can result in torque on the magnetization, which provides a way to detect the orbital Hall effect. With this motivation, we examine the current-induced spin-orbit torques in various ferromagnet/heavy metal bilayers by theory and experiment. Analysis of the magnetic torque reveals the presence of the contribution from the orbital Hall effect in the heavy metal, which competes with the contribution from the spin Hall effect. In particular, we find that the net torque in Ni/Ta bilayers is opposite in sign to the spin Hall theory prediction but instead consistent with the orbital Hall theory, which unambiguously confirms the orbital torque generated by the orbital Hall effect. Our finding opens a possibility of utilizing the orbital current for spintronic device applications, and it will invigorate researches on spin-orbit-coupled phenomena based on orbital engineering.

scholarly journals Acoustic spin Hall effect in strong spin-orbit metals

2021 ◽  
Vol 7 (2) ◽  
pp. eabd9697
Author(s):  
Takuya Kawada ◽  
Masashi Kawaguchi ◽  
Takumi Funato ◽  
Hiroshi Kohno ◽  
Masamitsu Hayashi
Keyword(s):  
Hall Effect ◽  
Spin Diffusion ◽  
Time Derivative ◽  
Spin Current ◽  
Spin Hall Effect ◽  
Spin Orbit ◽  
Lattice Displacement ◽  
Current Flows ◽  
Metal Bilayers ◽  
Strong Spin

We report on the observation of the acoustic spin Hall effect that facilitates lattice motion–induced spin current via spin-orbit interaction (SOI). Under excitation of surface acoustic wave (SAW), we find that a spin current flows orthogonal to the SAW propagation in nonmagnetic metals (NMs). The acoustic spin Hall effect manifests itself in a field-dependent acoustic voltage in NM/ferromagnetic metal bilayers. The acoustic voltage takes a maximum when the NM layer thickness is close to its spin diffusion length, vanishes for NM layers with weak SOI, and increases linearly with the SAW frequency. To account for these results, we find that the spin current must scale with the SOI and the time derivative of the lattice displacement. These results, which imply the strong coupling of electron spins with rotating lattices via the SOI, show the potential of lattice dynamics to supply spin current in strong spin-orbit metals.

Dynamics of Dzyaloshinskii Domain Walls Driven by Spin Hall Effect in the Presence of Magnetic Fields

SPIN ◽  
2017 ◽  
Vol 07 (01) ◽  
pp. 1740004
Author(s):  
Chengkun Song ◽  
Chendong Jin ◽  
Jianbo Wang ◽  
Qingfang Liu
Keyword(s):  
Magnetic Fields ◽  
Hall Effect ◽  
Domain Walls ◽  
Domain Wall Motion ◽  
Spin Hall Effect ◽  
Micromagnetic Simulations ◽  
Out Of Plane ◽  
Device Applications ◽  
Metal Bilayers ◽  
The Magnetic Field

Current-induced domain wall motion (CIDWM) in perpendicularly magnetized materials exhibits large potential in spintronic device applications. The Dzyaloshinskii domain walls (DWs) are nucleated in ultrathin ferromagnetic/heavy-metal bilayers with high perpendicular magnetocrystalline anisotropy (PMA) in the presence of interfacial Dzyaloshinskii–Moriya interaction (DMI). Here, we investigate the effect of magnetic fields on Dzyaloshinskii DWs driven by spin Hall effect (SHE) by means of micromagnetic simulations. We find that magnetic fields can modify the dynamics of Dzyaloshinskii DW. When applying out-of-plane magnetic fields, the velocity of Dzyaloshinskii DWs increases when the field-driven and current-driven DW motion are in same direction, while it decreases with opposite direction. In the case of in-plane longitudinal magnetic fields, Dzyaloshinskii DW velocity increases when the direction of the magnetic field and Dzyaloshinskii DW propagation direction are same, and it decreases when applying opposite in-plane magnetic fields. These manifestations may offer a new method for manipulating Dzyaloshinskii DWs and promise applications in DW-based nanodevices.

scholarly journals Deficiency of the bulk spin Hall effect model for spin-orbit torques in magnetic-insulator/heavy-metal heterostructures

2017 ◽  
Vol 95 (24) ◽  
Author(s):  
Junxue Li ◽  
Guoqiang Yu ◽  
Chi Tang ◽  
Yizhou Liu ◽  
Zhong Shi ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Hall Effect ◽  
Spin Hall Effect ◽  
Spin Orbit ◽  
Effect Model ◽  
Magnetic Insulator

scholarly journals Spin current generation in organic antiferromagnets

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Makoto Naka ◽  
Satoru Hayami ◽  
Hiroaki Kusunose ◽  
Yuki Yanagi ◽  
Yukitoshi Motome ◽  
...  
Keyword(s):  
Hall Effect ◽  
Spin Current ◽  
Inorganic Materials ◽  
Spin Hall Effect ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Current Generation ◽  
Heavy Atoms ◽  
A Charge

Abstract Spin current–a flow of electron spins without a charge current–is an ideal information carrier free from Joule heating for electronic devices. The celebrated spin Hall effect, which arises from the relativistic spin-orbit coupling, enables us to generate and detect spin currents in inorganic materials and semiconductors, taking advantage of their constituent heavy atoms. In contrast, organic materials consisting of molecules with light elements have been believed to be unsuited for spin current generation. Here we show that a class of organic antiferromagnets with checker-plate type molecular arrangements can serve as a spin current generator by applying a thermal gradient or an electric field, even with vanishing spin-orbit coupling. Our findings provide another route to create a spin current distinct from the conventional spin Hall effect and open a new field of spintronics based on organic magnets having advantages of small spin scattering and long lifetime.

scholarly journals Inverse spin Hall effect from pulsed spin current in organic semiconductors with tunable spin–orbit coupling

2016 ◽  
Vol 15 (8) ◽  
pp. 863-869 ◽  
Author(s):  
Dali Sun ◽  
Kipp J. van Schooten ◽  
Marzieh Kavand ◽  
Hans Malissa ◽  
Chuang Zhang ◽  
...  
Keyword(s):  
Hall Effect ◽  
Organic Semiconductors ◽  
Spin Current ◽  
Spin Hall Effect ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Inverse Spin Hall Effect

scholarly journals Spin current and spin magnetoresistance of the heterostructure iridate/manganite interface

2021 ◽  
Vol 13 (4) ◽  
pp. 479-486
Author(s):  
Gennady A. Ovsyannikov ◽  
◽  
Karen Y. Constantinian ◽  
Vladislav A. Shmakov ◽  
Anton V. Shadrin ◽  
...  
Keyword(s):  
Transition Metals ◽  
Hall Effect ◽  
Angular Dependence ◽  
Experimental Studies ◽  
Spin Current ◽  
Orbit Interaction ◽  
Spin Hall Effect ◽  
Spin Orbit ◽  
Inverse Spin Hall Effect ◽  
Academy Of Sciences

Kotelnikov Institute of Radioengineering and Electronics of Russian Academy of Sciences The paper presents the results of fabrication and structural study of SrIrO3/La0.7Sr0.3MnO3 heterostructures. The results of experimental studies of the spin current arising in the regime of ferromagnetic resonance are presented. The spin-orbit interaction present in 5d-oxides of transition metals, which is SrIrO3, provides an effective conversion of spin current to charge current due to the inverse spin Hall effect. The angular dependence of spin magnetoresistance makes it possible to determine the angle of the spin Hall effect.

scholarly journals Giant intrinsic spin Hall effect in W3Ta and other A15 superconductors

2019 ◽  
Vol 5 (4) ◽  
pp. eaav8575 ◽  
Author(s):  
E. Derunova ◽  
Y. Sun ◽  
C. Felser ◽  
S. S. P. Parkin ◽  
B. Yan ◽  
...  
Keyword(s):  
Hall Effect ◽  
Spin Current ◽  
Spin Hall Effect ◽  
High Symmetry ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Berry Curvature ◽  
Heavy Atoms ◽  
Simple Strategy ◽  
Nonmagnetic Metals

The spin Hall effect (SHE) is the conversion of charge current to spin current, and nonmagnetic metals with large SHEs are extremely sought after for spintronic applications, but their rarity has stifled widespread use. Here, we predict and explain the large intrinsic SHE in β-W and the A15 family of superconductors: W3Ta, Ta3Sb, and Cr3Ir having spin Hall conductivities (SHCs) of −2250, −1400, and 1210 ℏe(S/cm), respectively. Combining concepts from topological physics with the dependence of the SHE on the spin Berry curvature (SBC) of the electronic bands, we propose a simple strategy to rapidly search for materials with large intrinsic SHEs based on the following ideas: High symmetry combined with heavy atoms gives rise to multiple Dirac-like crossings in the electronic structure; without sufficient symmetry protection, these crossings gap due to spin-orbit coupling; and gapped crossings create large SBC.

scholarly journals Orbital torque in magnetic bilayers

2021 ◽  
Author(s):  
Dongjoon Lee ◽  
Dongwook Go ◽  
Hyeon-Jong Park ◽  
Wonmin Jeong ◽  
Hye-Won Ko ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Electric Field ◽  
Hall Effect ◽  
Spin Hall Effect ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Spin Currents ◽  
Fundamental Process ◽  
Metal Bilayers

Abstract The spin Hall effect describes an electric-field-induced generation of spin currents through spin-orbit coupling. Since the spin-orbit coupling alone cannot generate the angular momentum, there must be a more fundamental process of the spin Hall effect. Theories suggested that an electric-field-induced generation of orbital currents, called orbital Hall effect, is the fundamental process, and spin currents are subsequently converted from orbital currents. Despite its fundamental importance, the orbital Hall effect has not been confirmed experimentally. Motivated by a recent theoretical proposal of torque generation by orbital angular momentum injection, we examine the current-induced torque experimentally in various ferromagnet/heavy metal bilayers. We find that the net torque in Ni/Ta bilayers is opposite in sign to the spin Hall theory prediction but instead consistent with the orbital Hall theory, which confirms the orbital torque generated by the orbital Hall effect. It will invigorate researches on spin-orbit-coupled phenomena based on orbital engineering.

scholarly journals Neuromorphic computing based on an antiferromagnet-heavy metal hybrid structure under the action of laser pulses

2021 ◽  
Vol 2127 (1) ◽  
pp. 012023
Author(s):  
A Yu Mitrofanova ◽  
A R Safin ◽  
O V Kravchenko
Keyword(s):  
Heavy Metal ◽  
Hall Effect ◽  
Metal Layer ◽  
Spin Current ◽  
Optical Excitation ◽  
Laser Pulses ◽  
Hybrid Structure ◽  
Spin Hall Effect ◽  
Neuromorphic Computing ◽  
Magnetic Oscillations

Abstract The paper proposes a model of a neuromorphic processor, consisting of excitatory and processing neurons that are oscillators and detectors. The concept of neuromorphic computing, implemented by generating a spin current due to optical excitation of magnetic oscillations in an antiferromagnet is considered. The inverse spin Hall effect causes the generation of an electric current in the heavy metal layer. A constant driving current flows through the common bus. Magnetic oscillations in the receiving neuron occur due to the spin Hall effect. A biaxial nickel oxide crystal was used as a material for the base cells of AFM insulators and platinum was utilized as a heavy metal. The use of optical excitation can significantly increase the processing speed of neuromorphic computing with low power consumption. The presented model implements the simplest operations of neuromorphic computations, such as logical “OR”, “AND”.

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