scholarly journals Discrimination of Skyrmion Chirality Via Spin-Orbit and -Transfer Torques for Logic Operation

2021 ◽  
Author(s):  
Yoshinobu Nakatani ◽  
Keisuke Yamada ◽  
Atsufumi Hirohata
Keyword(s):  
Thin Film ◽  
Building Block ◽  
Logic Circuits ◽  
Spin Transfer Torque ◽  
Spin Transfer ◽  
Spin Orbit ◽  
Electrical Detection ◽  
Magnetic Thin Film ◽  
Logic Operation ◽  
Fundamental Building Block

Abstract Recently many works on magnetic memories and logic circuits, which use a magnetic skyrmion have been reported. Previously we micromagnetically simulated a method to switch a chirality of a magnetic skyrmion formed in a magnetic thin film by introducing a pulsed heat spot. In this paper, we propose a method to discriminate the chirality of a skyrmion in a branched nanowire by using spin-orbit torque (SOT) and spin-transfer torque (STT), and confirm the validity of the method by using simulation. The simulated results show that the motion changes depending on the chirality when additional SOT is applied on a skyrmion moving in a branch by STT. This method can be used as a fundamental building block for electrical detection in memory and logic devices using the chirality of skyrmions as a data bit in addition to the presence (and polarity) of the skyrmions as conventionally used, which can be lead to multiple-valued operation.

scholarly journals Discrimination of skyrmion chirality via spin–orbit and –transfer torques for logic operation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yoshinobu Nakatani ◽  
Keisuke Yamada ◽  
Atsufumi Hirohata
Keyword(s):  
Thin Film ◽  
Building Block ◽  
Logic Circuits ◽  
Spin Transfer Torque ◽  
Spin Transfer ◽  
Spin Orbit ◽  
Electrical Detection ◽  
Magnetic Thin Film ◽  
Logic Operation ◽  
Fundamental Building Block

AbstractRecently many works on magnetic memories and logic circuits, which use a magnetic skyrmion have been reported. Previously we micromagnetically simulated a method to switch a chirality of a magnetic skyrmion formed in a magnetic thin film by introducing a pulsed heat spot. In this paper, we propose a method to discriminate the chirality of a skyrmion in a branched nanowire by using spin–orbit torque (SOT) and spin-transfer torque (STT), and confirm the validity of the method by using simulation. The simulated results show that the motion changes depending on the chirality when additional SOT is applied on a skyrmion moving in a branch by STT. This method can be used as a fundamental building block for electrical detection in memory and logic devices using the chirality of skyrmions as a data bit in addition to the presence (and polarity) of the skyrmions as conventionally used, which can be lead to multiple-valued operation.

scholarly journals Current-induced spin–orbit torques

2011 ◽  
Vol 369 (1948) ◽  
pp. 3175-3197 ◽  
Author(s):  
Pietro Gambardella ◽  
Ioan Mihai Miron
Keyword(s):  
Angular Momentum ◽  
Exchange Coupling ◽  
Spin Transfer Torque ◽  
Spin Transfer ◽  
Spin Torque ◽  
Inversion Symmetry ◽  
Spin Orbit ◽  
Great Flexibility ◽  
Combined Action ◽  
Proper Material

The ability to reverse the magnetization of nanomagnets by current injection has attracted increased attention ever since the spin-transfer torque mechanism was predicted in 1996. In this paper, we review the basic theoretical and experimental arguments supporting a novel current-induced spin torque mechanism taking place in ferromagnetic (FM) materials. This effect, hereafter named spin–orbit (SO) torque, is produced by the flow of an electric current in a crystalline structure lacking inversion symmetry, which transfers orbital angular momentum from the lattice to the spin system owing to the combined action of SO and exchange coupling. SO torques are found to be prominent in both FM metal and semiconducting systems, allowing for great flexibility in adjusting their orientation and magnitude by proper material engineering. Further directions of research in this field are briefly outlined.

scholarly journals Multiple purpose spin transfer torque operated devices

2013 ◽  
Vol 26 (3) ◽  
pp. 227-238
Author(s):  
Thomas Windbacher ◽  
Hiwa Mahmoudi ◽  
Alexander Makarov ◽  
Viktor Sverdlov ◽  
Siegfried Selberherr
Keyword(s):  
Information Processing ◽  
Building Block ◽  
Energy Efficient ◽  
Spin Transfer Torque ◽  
Spin Transfer ◽  
Spin Torque ◽  
Logic Device ◽  
Flip Flop ◽  
Sequential Logic ◽  
Efficient Information

We summarize our recent work on a non-volatile logic building block required for energy-efficient information processing systems. A sequential logic device, in particular, an alternative non-volatile magnetic flip-flop has been introduced. Its properties are investigated and its extension to a very dense shift register is demonstrated. We show that the flip-flop structure inherently exhibits oscillations and discuss its spin torque nano-oscillator properties.

scholarly journals Theoretical Study of Field-Free Switching in PMA-MTJ Using Combined Injection of STT and SOT Currents

Micromachines ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1345
Author(s):  
Shaik Wasef ◽  
Hossein Fariborzi
Keyword(s):  
Critical Current ◽  
Theoretical Study ◽  
Tunnel Junctions ◽  
Spin Transfer Torque ◽  
Spin Transfer ◽  
Spin Orbit ◽  
Micromagnetic Simulations ◽  
Spintronic Devices ◽  
Current Densities ◽  
The Relationship

Field-free switching in perpendicular magnetic tunnel junctions (P-MTJs) can be achieved by combined injection of spin-transfer torque (STT) and spin-orbit torque (SOT) currents. In this paper, we derived the relationship between the STT and SOT critical current densities under combined injection. We included the damping–like torque (DLT) and field-like torque (FLT) components of both the STT and SOT. The results were derived when the ratio of the FLT to the DLT component of the SOT was positive. We observed that the relationship between the critical SOT and STT current densities depended on the damping constant and the magnitude of the FLT component of the STT and the SOT current. We also noted that, unlike the FLT component of SOT, the magnitude and sign of the FLT component of STT did not have a significant effect on the STT and SOT current densities required for switching. The derived results agreed well with micromagnetic simulations. The results of this work can serve as a guideline to model and develop spintronic devices using a combined injection of STT and SOT currents.

scholarly journals Single-shot dynamics of spin–orbit torque and spin transfer torque switching in three-terminal magnetic tunnel junctions

2020 ◽  
Vol 15 (2) ◽  
pp. 111-117 ◽  
Author(s):  
Eva Grimaldi ◽  
Viola Krizakova ◽  
Giacomo Sala ◽  
Farrukh Yasin ◽  
Sébastien Couet ◽  
...  
Keyword(s):  
Tunnel Junctions ◽  
Magnetic Tunnel Junctions ◽  
Spin Transfer Torque ◽  
Spin Transfer ◽  
Single Shot ◽  
Spin Orbit

scholarly journals Challenges in Characterizations of MTJ Thin Film Stack for Spin-transfer Torque MRAM Device by Analytical TEM in Wafer-foundries

2020 ◽  
Vol 26 (S2) ◽  
pp. 2820-2821
Author(s):  
Wayne Zhao ◽  
Hemant Dixit ◽  
Travis Mitchell ◽  
William Taylor
Keyword(s):  
Thin Film ◽  
Spin Transfer Torque ◽  
Spin Transfer ◽  
Analytical Tem
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