Control of Domain Wall Position by Electrical Current in Structured Co/Ni Wire with Perpendicular Magnetic Anisotropy

Koyama, Tanetoshi; Yamada, Gen; Tanigawa, H.; Kasai, S.; Ohshima, Norikazu; Fukami, Shunsuke; Ishiwata, N.; Nakatani, Yoshinobu; Ono, Teruo

doi:10.1143/apex.1.101303

Cited by 98 publications

(61 citation statements)

References 38 publications

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“…Subsequently, it was theoretically predicted that by using perpendicular-easy-axis systems with a reduced wire thickness, the hard-axis anisotropy, which governs J th in the adiabatic regime becomes so small that a DW can be moved by the adiabatic STT at a reasonably small current density. 66,67) Following the theoretical prediction, experimental studies using a perpendicular-easy-axis Co=Ni multilayer demonstrated DW motion driven with a small current density, [68][69][70][71] as explained well by the adiabatic-STT model. 71) In this system, the independence between J th and H C was also confirmed.…”

Section: Structure and Characteristics Of Three-terminal Spintronics supporting

confidence: 57%

Magnetization switching schemes for nanoscale three-terminal spintronics devices

Fukami

Ohno

2017

Jpn. J. Appl. Phys.

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Utilizing spintronics-based nonvolatile memories in integrated circuits offers a promising approach to realize ultralow-power and high-performance electronics. While two-terminal devices with spin-transfer torque switching have been extensively developed nowadays, there has been a growing interest in devices with a three-terminal structure. Of primary importance for applications is the efficient manipulation of magnetization, corresponding to information writing, in nanoscale devices. Here we review the studies of current-induced domain wall motion and spin-orbit torque-induced switching, which can be applied to the write operation of nanoscale three-terminal spintronics devices. For domain wall motion, the size dependence of device properties down to less than 20 nm will be shown and the underlying mechanism behind the results will be discussed. For spin-orbit torque-induced switching, factors governing the threshold current density and strategies to reduce it will be discussed. A proof-ofconcept demonstration of artificial intelligence using an analog spin-orbit torque device will also be reviewed.

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Section: Structure and Characteristics Of Three-terminal Spintronics supporting

confidence: 57%

Magnetization switching schemes for nanoscale three-terminal spintronics devices

Fukami

Ohno

2017

Jpn. J. Appl. Phys.

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“…Besides fundamental investigations, the use of domain walls in logic 19 and memory 20 devices has already been proposed. Low current densities and high domain wall (DW) velocities at zero magnetic field are required for future applications.Direct evidence of CIDM at zero field has been reported for several nanostripe systems, including permalloy (FeNi) 6,11 , magnetic semiconductors 9 and systems with perpendicular magnetization 7,12,14,15 . For the commonly used FeNi system, the critical current densities are not much below 10 12 A/m 2 at zero magnetic field 8,11 , associated with DW velocities going from some m/s up to about 100 m/s 11 .…”

mentioning

confidence: 99%

“…Since the prediction of spin-torque effects 2 , many experimental 3,4,5,6,7,8,9,10,11,12,13,14,15 and theoretical 16,17,18 works have been dedicated to the study of currentinduced domain wall motion (CIDM). Besides fundamental investigations, the use of domain walls in logic 19 and memory 20 devices has already been proposed.…”

mentioning

confidence: 99%

High Domain Wall Velocity at Zero Magnetic Field Induced by Low Current Densities in Spin Valve Nanostripes

Pizzini

Uhlíř

Vogel

et al. 2009

Appl. Phys. Express

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Current-induced magnetic domain wall motion at zero magnetic field is observed in the permalloy layer of a spin-valve-based nanostripe using photoemission electron microscopy. The domain wall movement is hampered by pinning sites, but in between them high domain wall velocities (exceeding 150 m/s) are obtained for current densities well below 10 12 A/m 2 , suggesting that these trilayer systems are promising for applications in domain wall devices in case of well controlled pinning positions. Vertical spin currents in these structures provide a potential explanation for the increase in domain wall velocity at low current densities.Moving magnetic domain walls using electric currents via spin-torque effects rather than using a magnetic field is one of the recent exciting developments in spintronics 1 . Since the prediction of spin-torque effects 2 , many experimental 3,4,5,6,7,8,9,10,11,12,13,14,15 and theoretical 16,17,18 works have been dedicated to the study of currentinduced domain wall motion (CIDM). Besides fundamental investigations, the use of domain walls in logic 19 and memory 20 devices has already been proposed. Low current densities and high domain wall (DW) velocities at zero magnetic field are required for future applications.Direct evidence of CIDM at zero field has been reported for several nanostripe systems, including permalloy (FeNi) 6,11 , magnetic semiconductors 9 and systems with perpendicular magnetization 7,12,14,15 . For the commonly used FeNi system, the critical current densities are not much below 10 12 A/m 2 at zero magnetic field 8,11 , associated with DW velocities going from some m/s up to about 100 m/s 11 . Much lower critical currents are found for magnetic semiconductors like GaMnAs (about 1 × 10 9 A/m 2 ) because of the low magnetic moments, but the observed DW velocities are small (< 1 m/s) 9 . Moreover, these materials are not ferromagnetic at room temperature. Low current density values are also found in spin-valve-based nanostripes with either in-plane 3,10 or perpendicular anisotropy 7 . Additionally, transport measurements in FeNi/Cu/Co trilayers show CIDM induced by subnanosecond current pulses 5 , indirectly indicating high DW velocities in such spin-valve-based systems. In this work, we show that in these systems CIDM at zero magnetic field can take place with high DW velocities (exceeding 150 m/s) at current densities well below 10 12 A/m 2 . These high velocities are observed only in certain regions of the nanostripes, where domain wall pinning is limited. Currents perpendicular to the plane in the vicinity of the DW are probably partly responsible for this increase in efficiency, which makes the trilayer systems possible candidates for spintronic applications based on CIDM if pinning can be controlled.We observed domain wall motion in the FeNi layer of 400 nm wide FeNi (5 nm)/Cu (8 nm)/Co (7 nm)/ CoO (3 nm) nanostripes, by using Photoemission Electron Microscopy (PEEM) combined with X-ray Magnetic Circular Dichroism (XMCD) 21 . The Cu spacer layer is chosen to ...

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“…Each magnetic layer is assumed to be Co/Ni multilayer. 13 The stable magnetic domain wall structure in each layer can be determined by the exchange coupling strength J ex and the wire width. The exchange stiffness constant A is 1.0 × 10 −6 erg/cm, the uniaxial anisotropy constant K u is 4.0 × 10 6 erg/cm 3 , the saturation magnetization M s is 600 emu/cm 3 and the interlayer exchange coupling J ex t is varied from −0.5 erg/cm 2 to 0.5 erg/cm 2 .…”

Section: Methodsmentioning

confidence: 99%

Micromagnetic analysis of current-induced domain wall motion in a bilayer nanowire with synthetic antiferromagnetic coupling

Komine

Aono

2016

AIP Advances

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We demonstrate current-induced domain wall motion in bilayer nanowire with synthetic antiferromagnetic (SAF) coupling by modeling two body problems for motion equations of domain wall. The influence of interlayer exchange coupling and magnetostatic interactions on current-induced domain wall motion in SAF nanowires was also investigated. By assuming the rigid wall model for translational motion, the interlayer exchange coupling and the magnetostatic interaction between walls and domains in SAF nanowires enhances domain wall speed without any spin-orbit-torque. The enhancement of domain wall speed was discussed by energy distribution as a function of wall angle configuration in bilayer nanowires.

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Control of Domain Wall Position by Electrical Current in Structured Co/Ni Wire with Perpendicular Magnetic Anisotropy

Cited by 98 publications

References 38 publications

Magnetization switching schemes for nanoscale three-terminal spintronics devices

Magnetization switching schemes for nanoscale three-terminal spintronics devices

High Domain Wall Velocity at Zero Magnetic Field Induced by Low Current Densities in Spin Valve Nanostripes

Micromagnetic analysis of current-induced domain wall motion in a bilayer nanowire with synthetic antiferromagnetic coupling

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