PERFECT ALLOYS FOR SPIN HALL CURRENT-INDUCED MAGNETIZATION SWITCHING

SPIN ◽  
2012 ◽  
Vol 02 (02) ◽  
pp. 1250010 ◽  
Author(s):  
MARTIN GRADHAND ◽  
DMITRY V. FEDOROV ◽  
PETER ZAHN ◽  
INGRID MERTIG ◽  
YOSHICHIKA OTANI ◽  
...  
Keyword(s):  
Hall Effect ◽  
Noble Metals ◽  
Spin Diffusion ◽  
Spin Current ◽  
Material Design ◽  
Spin Hall Effect ◽  
Pure Spin ◽  
Magnetization Switching ◽  
Hall Angle ◽  
Electronic Measurement

We propose a device that allows for magnetization switching in nanomagnets by means of a pure spin current induced by the spin Hall effect. For this purpose we combine the ideas of magnetization switching of a ferromagnet by a spin current produced via the spin accumulation at a ferromagnet/nonmagnet interface with the electronic measurement of the direct spin Hall effect, and the theoretical material design to identify systems with a large spin Hall angle and an appropriate spin diffusion length. We will discuss the device design with respect to the size of the charge and spin currents. Based on ab initio calculations, we predict dilute alloys ideally suited for this application. Noble metals with single-sheeted Fermi surfaces, doped with either heavy impurities like Bi and Pb in Cu or Bi in Ag and light impurities like C and N in Au , seem to be the best candidates for a spin Hall angle larger than 5%.

scholarly journals NONLOCAL ELECTRONIC SPIN DETECTION, SPIN ACCUMULATION AND THE SPIN HALL EFFECT

2009 ◽  
Vol 23 (11) ◽  
pp. 2413-2438 ◽  
Author(s):  
SERGIO O. VALENZUELA
Keyword(s):  
Hall Effect ◽  
Spin Diffusion ◽  
Spin Injection ◽  
Spin Hall Effect ◽  
Current Status ◽  
Pure Spin ◽  
Spin Accumulation ◽  
Spin Currents ◽  
Electrical Spin ◽  
Spin Detection

In recent years, electrical spin injection and detection has grown into a lively area of research in the field of spintronics. Spin injection into a paramagnetic material is usually achieved by means of a ferromagnetic source, whereas the induced spin accumulation or associated spin currents are detected by means of a second ferromagnet or the reciprocal spin Hall effect, respectively. This article reviews the current status of this subject, describing both recent progress and well-established results. The emphasis is on experimental techniques and accomplishments that brought about important advances in spin phenomena and possible technological applications. These advances include, amongst others, the characterization of spin diffusion and precession in a variety of materials, such as metals, semiconductors and graphene, the determination of the spin polarization of tunneling electrons as a function of the bias voltage, and the implementation of magnetization reversal in nanoscale ferromagnetic particles with pure spin currents.

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.

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.

Conversion of spin current into charge current at room temperature: Inverse spin-Hall effect

2006 ◽  
Vol 88 (18) ◽  
pp. 182509 ◽  
Author(s):  
E. Saitoh ◽  
M. Ueda ◽  
H. Miyajima ◽  
G. Tatara
Keyword(s):  
Hall Effect ◽  
Room Temperature ◽  
Spin Current ◽  
Spin Hall Effect ◽  
Charge Current ◽  
Inverse Spin Hall Effect

scholarly journals Giant spin-accumulation signal and pure spin-current-induced reversible magnetization switching

2008 ◽  
Vol 4 (11) ◽  
pp. 851-854 ◽  
Author(s):  
Tao Yang ◽  
Takashi Kimura ◽  
Yoshichika Otani
Keyword(s):  
Spin Current ◽  
Pure Spin ◽  
Spin Accumulation ◽  
Magnetization Switching ◽  
Reversible Magnetization

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.

Spin Pumping in a Ferromagnetic/Nonmagnetic/Spin-Sink Trilayer Film: Spin Current Termination

2012 ◽  
Vol 508 ◽  
pp. 266-270 ◽  
Author(s):  
K. Harii ◽  
Z. Qiu ◽  
T. Iwashita ◽  
Y. Kajiwara ◽  
K. Uchida ◽  
...  
Keyword(s):  
Diffusion Equation ◽  
Hall Effect ◽  
Spin Diffusion ◽  
Diffusion Length ◽  
Spin Current ◽  
Interlayer Thickness ◽  
Spin Pumping ◽  
Charge Current ◽  
Inverse Spin Hall Effect ◽  
Spin Diffusion Length

A Spin Current Generated by Spin Pumping in a Ferromagnetic/Nonmagnetic/Spin-Sink Trilayer Film Is Calculated Based on the Spin Pumping Theory and the Standard Spin Diffusion Equation. By Attaching the Spin-Sink Layer, the Injected Spin Current Is Drastically Enhanced when the Interlayer Thickness Is Shorter than the Spin Diffusion Length of the Interlayer. We Also Provided the Formula of the Charge Current which Is Induced from the Pumped Spin Current via the Inverse Spin-Hall Effect.

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