scholarly journals Spin current related magnetoresistance in epitaxial Pt/Co bilayers in the presence of spin Hall effect and Rashba-Edelstein effect

2021 ◽  
Vol 103 (9) ◽  
Author(s):  
Ye Du ◽  
Saburo Takahashi ◽  
Junsaku Nitta
Keyword(s):  
Hall Effect ◽  
Spin Current ◽  
Spin Hall Effect

scholarly journals Anomalous spin Hall and inverse spin Hall effects in magnetic systems

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
X. R. Wang
Keyword(s):  
Hall Effect ◽  
Order Parameter ◽  
Spin Current ◽  
Spin Hall Effect ◽  
Magnetic Systems ◽  
Charge Current ◽  
Spin Currents ◽  
Tensor Quantity ◽  
Hall Effects ◽  
Spin Hall Effects

AbstractSpin current is a very important tensor quantity in spintronics. However, the well-known spin-Hall effect (SHE) can only generate a few of its components whose propagating and polarization directions are perpendicular with each other and to an applied charge current. It is highly desirable in applications to generate spin currents whose polarization can be in any possible direction. Here anomalous SHE and inverse spin-Hall effect (ISHE) in magnetic systems are predicted. Spin currents, whose polarisation and propagation are collinear or orthogonal with each other and along or perpendicular to the charge current, can be generated, depending on whether the applied charge current is along or perpendicular to the order parameter. In anomalous ISHEs, charge currents proportional to the order parameter can be along or perpendicular to the propagating or polarization directions of the spin current.

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 A New Approach to Transport Coefficients in the Quantum Spin Hall Effect

2020 ◽  
Author(s):  
Giovanna Marcelli ◽  
Gianluca Panati ◽  
Stefan Teufel
Keyword(s):  
Hall Effect ◽  
Constant Electric Field ◽  
Transport Coefficients ◽  
Spin Current ◽  
Spin Operator ◽  
Quantum Spin ◽  
Spin Hall Effect ◽  
Current Operator ◽  
Quantum Spin Hall Effect ◽  
Quantum Spin Hall

AbstractWe investigate some foundational issues in the quantum theory of spin transport, in the general case when the unperturbed Hamiltonian operator $$H_0$$ H 0 does not commute with the spin operator in view of Rashba interactions, as in the typical models for the quantum spin Hall effect. A gapped periodic one-particle Hamiltonian $$H_0$$ H 0 is perturbed by adding a constant electric field of intensity $$\varepsilon \ll 1$$ ε ≪ 1 in the j-th direction, and the linear response in terms of a S-current in the i-th direction is computed, where S is a generalized spin operator. We derive a general formula for the spin conductivity that covers both the choice of the conventional and of the proper spin current operator. We investigate the independence of the spin conductivity from the choice of the fundamental cell (unit cell consistency), and we isolate a subclass of discrete periodic models where the conventional and the proper S-conductivity agree, thus showing that the controversy about the choice of the spin current operator is immaterial as far as models in this class are concerned. As a consequence of the general theory, we obtain that whenever the spin is (almost) conserved, the spin conductivity is (approximately) equal to the spin-Chern number. The method relies on the characterization of a non-equilibrium almost-stationary state (NEASS), which well approximates the physical state of the system (in the sense of space-adiabatic perturbation theory) and allows moreover to compute the response of the adiabatic S-current as the trace per unit volume of the S-current operator times the NEASS. This technique can be applied in a general framework, which includes both discrete and continuum models.

Experimental observation of the spin Hall effect using spin dynamics

2017 ◽  
Author(s):  
E. Saitoh ◽  
K. Ando
Keyword(s):  
Hall Effect ◽  
Field Component ◽  
Resonance Condition ◽  
Spin Dynamics ◽  
Ferromagnetic Layer ◽  
Spin Current ◽  
Spin Hall Effect ◽  
Microwave Cavity ◽  
Bilayer Film ◽  
Spin Pumping

This chapter describes an experiment on the inverse spin Hall effect (ISHE) induced by spin pumping. Spin pumping is the generation of spin currents as a result of magnetization M(t) precession; in a ferromagnetic/paramagnetic bilayer system, a conduction-electron spin current is pumped out of the ferromagnetic layer into the paramagnetic conduction layer in a ferromagnetic resonance condition. The sample used in the experiment is a Ni81Fe19/Pt bilayer film comprising a 10-nm-thick ferromagnetic Ni81Fe19layer and a 10-nm-thick paramagnetic Pt layer. For the measurement, the sample system is placed near the centre of a TE011 microwave cavity at which the magnetic-field component of the microwave mode is maximized while the electric-field component is minimized.

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.

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