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

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.

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Orbital torque in magnetic bilayers

Nature Communications ◽

10.1038/s41467-021-26650-9 ◽

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.

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INFLUENCE OF MAGNETIC FIELDS ON THE INTRINSIC SPIN HALL EFFECT IN TWO-DIMENSIONAL SYSTEMS

International Journal of Modern Physics B ◽

10.1142/s0217979209061998 ◽

2009 ◽

Vol 23 (12n13) ◽

pp. 2566-2572 ◽

Cited By ~ 1

Author(s):

O. E. RAICHEV

Keyword(s):

Magnetic Field ◽

Magnetic Fields ◽

Hall Effect ◽

Berry Phase ◽

Zeeman Splitting ◽

Hall Conductivity ◽

Spin Hall Effect ◽

Two Dimensional ◽

The Magnetic Field ◽

Spin Hall Conductivity

The influence of magnetic fields on the electron spin in solids involves two basic mechanisms. First, any magnetic field introduces the Zeeman splitting of electron states, thereby modifying spin precession. Second, since the magnetic field affects the electron motion in the plane perpendicular to the field, the spin dynamics is also modified, owing to the spin-orbit interaction. The theory predicts, as a consequence of this influence, unusual properties of the intrinsic spin-Hall effect in two-dimensional systems in the presence of magnetic fields. This paper describes non-monotonic dependence of the spin-Hall conductivity on the magnetic field and its enhancement in the case of weak disorder, as well as multiple jumps of the spin-Hall conductivity owing to the topological transitions (abrupt changes of the Berry phase) induced by the parallel magnetic field.

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Magnetostrictive Self-Diagnosing Smart Bolts

Volume 14: Emerging Technologies; Engineering Management, Safety, Ethics, Society, and Education; Materials: Genetics to Structures ◽

10.1115/imece2014-38622 ◽

2014 ◽

Author(s):

Vladislav Sevostianov

Keyword(s):

Magnetic Field ◽

Plastic Deformation ◽

Magnetic Fields ◽

Hall Effect ◽

Stress Level ◽

Experimental Validation ◽

Rock Bolts ◽

Three Point Bending ◽

Bending Loading ◽

The Magnetic Field

The paper presents the concept of self-diagnosing smart bolts and its experimental validation. In the present research such bolts are designed, built, and experimentally tested. As a key element of the design, wires of Galfenol (alloy of iron and gallium) are used. This material shows magnetostrictive properties, and, at the same time, is sufficiently ductile to follow typical deformation of rock bolts, and is economically affordable. Two types of Galfenol were used: Ga10Fe90 and Ga17Fe83. The wires have been installed in bolts using two designs — in a drilled central hole or in a cut along the side — and the bolts were tested for generation of the magnetic field under three-point bending loading. To measure the magnetic field in the process of deformation, a magnetometer that utilizes the GMR effect was designed, built, and compared with one utilizing the Hall effect. It is shown that (1) magnetic field generated by deformation of the smart bolts at the stress level of plastic deformation is sufficient to be noticed by the proposed magnetometer; however, the magnetometer using Hall effect is insufficient; (2) Ga10Fe90 produces higher magnetic fields than Ga17Fe83; (3) the magnetic field in plastically bended bolts is relatively stable with time.

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MAGNETIC RACE-TRACK — A NOVEL STORAGE CLASS SPINTRONIC MEMORY

International Journal of Modern Physics B ◽

10.1142/s0217979208046190 ◽

2008 ◽

Vol 22 (01n02) ◽

pp. 117-118 ◽

Cited By ~ 1

Author(s):

STUART PARKIN

Keyword(s):

Domain Wall ◽

Tunnel Junction ◽

Domain Walls ◽

Magnetic Tunnel Junction ◽

Domain Wall Motion ◽

Wall Structure ◽

Micromagnetic Simulations ◽

Confining Potential ◽

Current Pulses ◽

Race Track

A proposal for a novel storage-class memory is described in which magnetic domains are used to store information in a "magnetic race-track".1 The magnetic race-track shift register storage memory promises a solid state memory with storage capacities and cost rivaling that of magnetic disk drives but with much improved performance and reliability. The magnetic race track is comprised of tall columns of magnetic material arranged perpendicularly to the surface of a silicon wafer. The domains are moved up and down the race-track by nanosecond long current pulses using the phenomenon of spin momentum transfer. The domain walls in the magnetic race-track are read using magnetic tunnel junction magnetoresistive sensing devices arranged in the silicon substrate. Recent progress in developing magnetic tunnel junction devices with giant tunneling magnetoresistance exceeding 350% at room temperature will be mentioned.2 Experiments exploring the current induced motion and depinning of domain walls in magnetic nano-wires with artificial pinning sites will be discussed. The domain wall structure, whether vortex or transverse, and the magnitude of the pinning potential is shown to have surprisingly little effect on the current driven dynamics of the domain wall motion.3 By contrast the motion of DWs under nanosecond long current pulses is surprisingly sensitive to their length.4 In particular, we find that the probability of dislodging a DW, confined to a pinning site in a permalloy nanowire, oscillates with the length of the current pulse, with a period of just a few nanoseconds. Using an analytical model and micromagnetic simulations we show that this behaviour is connected to a current induced oscillatory motion of the DW. The period is determined by the DW mass and the curvature of the confining potential. When the current is turned off during phases of the DW motion when the DW has enough momentum, there is a boomerang effect that can drive the DW out of the confining potential in the opposite direction to the flow of spin angular momentum. Note from Publisher: This article contains the abstract only.

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Domain wall motion driven by spin Hall effect—Tuning with in-plane magnetic anisotropy

Applied Physics Letters ◽

10.1063/1.4873583 ◽

2014 ◽

Vol 104 (16) ◽

pp. 162408 ◽

Cited By ~ 9

Author(s):

A. W. Rushforth

Keyword(s):

Domain Wall ◽

Magnetic Anisotropy ◽

Hall Effect ◽

Wall Motion ◽

Domain Wall Motion ◽

Spin Hall Effect

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Magnetic Field Evolution in Neutron Star Crusts: Beyond the Hall Effect

Symmetry ◽

10.3390/sym14010130 ◽

2022 ◽

Vol 14 (1) ◽

pp. 130

Author(s):

Konstantinos N. Gourgouliatos ◽

Davide De Grandis ◽

Andrei Igoshev

Keyword(s):

Magnetic Field ◽

Magnetic Fields ◽

Neutron Stars ◽

Hall Effect ◽

Thermal Emission ◽

Ohmic Dissipation ◽

Field Evolution ◽

The Universe ◽

The Magnetic Field ◽

Maxwell Stresses

Neutron stars host the strongest magnetic fields that we know of in the Universe. Their magnetic fields are the main means of generating their radiation, either magnetospheric or through the crust. Moreover, the evolution of the magnetic field has been intimately related to explosive events of magnetars, which host strong magnetic fields, and their persistent thermal emission. The evolution of the magnetic field in the crusts of neutron stars has been described within the framework of the Hall effect and Ohmic dissipation. Yet, this description is limited by the fact that the Maxwell stresses exerted on the crusts of strongly magnetised neutron stars may lead to failure and temperature variations. In the former case, a failed crust does not completely fulfil the necessary conditions for the Hall effect. In the latter, the variations of temperature are strongly related to the magnetic field evolution. Finally, sharp gradients of the star’s temperature may activate battery terms and alter the magnetic field structure, especially in weakly magnetised neutron stars. In this review, we discuss the recent progress made on these effects. We argue that these phenomena are likely to provide novel insight into our understanding of neutron stars and their observable properties.

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Efficient Injection and Detection of Out-of-Plane Spins via the Anomalous Spin Hall Effect in Permalloy Nanowires

Nano Letters ◽

10.1021/acs.nanolett.8b02114 ◽

2018 ◽

Vol 18 (9) ◽

pp. 5633-5639 ◽

Cited By ~ 18

Author(s):

Kumar Sourav Das ◽

Jing Liu ◽

Bart J. van Wees ◽

Ivan J. Vera-Marun

Keyword(s):

Hall Effect ◽

Spin Hall Effect ◽

Out Of Plane

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Galvanomagnetic and thermomagnetic phenomena

Properties of Materials ◽

10.1093/oso/9780198520757.003.0022 ◽

2004 ◽

Author(s):

Robert E. Newnham

Keyword(s):

Magnetic Field ◽

Heat Flow ◽

Magnetic Fields ◽

Hall Effect ◽

Electric Current ◽

Lorentz Force ◽

Electrical Resistance ◽

Magnetic Flux Density ◽

Wide Range ◽

The Magnetic Field

The Lorentz force that a magnetic field exerts on a moving charge carrier is perpendicular to the direction of motion and to the magnetic field. Since both electric and thermal currents are carried by mobile electrons and ions, a wide range of galvanomagnetic and thermomagnetic effects result. The effects that occur in an isotropic polycrystalline metal are illustrated in Fig. 20.1. As to be expected, many more cross-coupled effects occur in less symmetric solids. The galvanomagnetic experiments involve electric field, electric current, and magnetic field as variables. The Hall Effect, transverse magnetoresistance, and longitudinal magnetoresistance all describe the effects of magnetic fields on electrical resistance. Analogous experiments on thermal conductivity are referred to as thermomagnetic effects. In this case the variables are heat flow, temperature gradient, and magnetic field. The Righi–Leduc Effect is the thermal Hall Effect in which magnetic fields deflect heat flow rather than electric current. The transverse thermal magnetoresistance (the Maggi–Righi–Leduc Effect) and the longitudinal thermal magnetoresistance are analogous to the two galvanomagnetic magnetoresistance effects. Additional interaction phenomena related to the thermoelectric and piezoresistance effects will be discussed in the next two chapters. In tensor form Ohm’s Law is . . .Ei = ρijJj , . . . where Ei is electrical field, Jj electric current density, and ρij the electrical resistivity in Ωm. In describing the effect of magnetic field on electrical resistance, we expand the resistivity in a power series in magnetic flux density B. B is used rather than the magnetic field H because the Lorentz force acting on the charge carriers depends on B not H.

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