Compact model of Domain Wall MTJ Driven by Spin Orbit Torque and Dzyaloshinskii–Moriya Interaction

2021 ◽  
pp. 1-1
Author(s):  
Manman Wang ◽  
Yanfeng Jiang
Keyword(s):  
Domain Wall ◽  
Compact Model ◽  
Spin Orbit ◽  
Moriya Interaction

scholarly journals Reducing Dzyaloshinskii-Moriya interaction and field-free spin-orbit torque switching in synthetic antiferromagnets

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ruyi Chen ◽  
Qirui Cui ◽  
Liyang Liao ◽  
Yingmei Zhu ◽  
Ruiqi Zhang ◽  
...  
Keyword(s):  
Domain Wall ◽  
Tunnel Junctions ◽  
Low Power Consumption ◽  
Stray Field ◽  
Magnetic Memory ◽  
Spin Orbit ◽  
Theoretic Analysis ◽  
Spintronic Devices ◽  
Deterministic Switching ◽  
Moriya Interaction

AbstractPerpendicularly magnetized synthetic antiferromagnets (SAF), possessing low net magnetization and high thermal stability as well as easy reading and writing characteristics, have been intensively explored to replace the ferromagnetic free layers of magnetic tunnel junctions as the kernel of spintronic devices. So far, utilizing spin-orbit torque (SOT) to realize deterministic switching of perpendicular SAF have been reported while a large external magnetic field is typically needed to break the symmetry, making it impractical for applications. Here, combining theoretic analysis and experimental results, we report that the effective modulation of Dzyaloshinskii-Moriya interaction by the interfacial crystallinity between ferromagnets and adjacent heavy metals plays an important role in domain wall configurations. By adjusting the domain wall configuration between Bloch type and Néel type, we successfully demonstrate the field-free SOT-induced magnetization switching in [Co/Pd]/Ru/[Co/Pd] SAF devices constructed with a simple wedged structure. Our work provides a practical route for utilization of perpendicularly SAF in SOT devices and paves the way for magnetic memory devices with high density, low stray field, and low power consumption.

scholarly journals Dzyaloshinskii–Moriya interaction in noncentrosymmetric superlattices

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Woo Seung Ham ◽  
Abdul-Muizz Pradipto ◽  
Kay Yakushiji ◽  
Kwangsu Kim ◽  
Sonny H. Rhim ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Degrees Of Freedom ◽  
Orbit Coupling ◽  
Inversion Symmetry ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Band Formation ◽  
Research Activities ◽  
Moriya Interaction

AbstractDzyaloshinskii–Moriya interaction (DMI) is considered as one of the most important energies for specific chiral textures such as magnetic skyrmions. The keys of generating DMI are the absence of structural inversion symmetry and exchange energy with spin–orbit coupling. Therefore, a vast majority of research activities about DMI are mainly limited to heavy metal/ferromagnet bilayer systems, only focusing on their interfaces. Here, we report an asymmetric band formation in a superlattices (SL) which arises from inversion symmetry breaking in stacking order of atomic layers, implying the role of bulk-like contribution. Such bulk DMI is more than 300% larger than simple sum of interfacial contribution. Moreover, the asymmetric band is largely affected by strong spin–orbit coupling, showing crucial role of a heavy metal even in the non-interfacial origin of DMI. Our work provides more degrees of freedom to design chiral magnets for spintronics applications.

scholarly journals Domain wall-magnetic tunnel junction spin–orbit torque devices and circuits for in-memory computing

2021 ◽  
Vol 118 (11) ◽  
pp. 112401
Author(s):  
Mahshid Alamdar ◽  
Thomas Leonard ◽  
Can Cui ◽  
Bishweshwor P. Rimal ◽  
Lin Xue ◽  
...  
Keyword(s):  
Domain Wall ◽  
Tunnel Junction ◽  
Magnetic Tunnel Junction ◽  
Spin Orbit

scholarly journals Electric field control of magnetic domain wall motion via modulation of the Dzyaloshinskii-Moriya interaction

2018 ◽  
Vol 4 (12) ◽  
pp. eaav0265 ◽  
Author(s):  
Tomohiro Koyama ◽  
Yoshinobu Nakatani ◽  
Jun’ichi Ieda ◽  
Daichi Chiba
Keyword(s):  
Domain Wall ◽  
Electric Field ◽  
Magnetic Domain ◽  
Domain Wall Motion ◽  
Asymmetric Structure ◽  
Velocity Change ◽  
Spintronic Devices ◽  
Electrical Manipulation ◽  
Substantial Change ◽  
Moriya Interaction

We show that the electric field (EF) can control the domain wall (DW) velocity in a Pt/Co/Pd asymmetric structure. With the application of a gate voltage, a substantial change in DW velocity up to 50 m/s is observed, which is much greater than that observed in previous studies. Moreover, modulation of a DW velocity exceeding 100 m/s is demonstrated in this study. An EF-induced change in the interfacial Dzyaloshinskii-Moriya interaction (DMI) up to several percent is found to be the origin of the velocity modulation. The DMI-mediated velocity change shown here is a fundamentally different mechanism from that caused by EF-induced anisotropy modulation. Our results will pave the way for the electrical manipulation of spin structures and dynamics via DMI control, which can enhance the performance of spintronic devices.

scholarly journals Giant Dzyaloshinskii-Moriya interaction in Rashba superlattices

2020 ◽  
Author(s):  
Woo-Seung Ham ◽  
Abdul-Muizz Pradipto ◽  
Kay Yakushiji ◽  
Kwangsu Kim ◽  
Sonny Rhim ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Material Design ◽  
Orbit Coupling ◽  
Inversion Symmetry ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Band Formation ◽  
Stacking Order ◽  
Magnetic Skyrmions ◽  
Moriya Interaction

Abstract Dzyaloshinskii-Moriya interaction (DMI) is considered as one of the most important energy for specific chiral texture such as magnetic skyrmions. The key of generating DMI is absence of structural inversion symmetry and exchange energy with spin-orbit coupling. Therefore, a vast majority of researches about DMI is mainly limited to heavy metal/ferromagnet bilayer systems, only focusing on their interfaces. Here, we report that asymmetric band formation in an artificial superlattice arises from inversion symmetry breaking in stacking order of atomic layers, resulting in bulk DMI. Such bulk DMI is more than 300% larger than simple sum of interfacial contribution. Moreover, the asymmetric band is largely affected by strong spin-orbit coupling, showing crucial role of a heavy metal even in the non-interfacial origin of DMI. Such Rashba superlattices can be a new class of material design for spintronics applications.

scholarly journals Voltage Controlled Domain Wall Motion based Neuron and Stochastic Magnetic Tunnel Junction Synapse for Neuromorphic Computing Applications

2021 ◽  
Author(s):  
Aijaz Lone ◽  
Selma Amara ◽  
Hossein Fariborzi
Keyword(s):  
Domain Wall ◽  
Tunnel Junction ◽  
Thermal Noise ◽  
Wall Motion ◽  
Magnetic Tunnel Junction ◽  
Domain Wall Motion ◽  
Spin Orbit ◽  
Free Layer ◽  
Digit Recognition ◽  
Transport Studies

The present work discusses the proposal of a spintronic neuromorphic system with spin orbit torque driven domain wall motion-based neuron and synapse. We propose a voltage-controlled magnetic anisotropy domain wall motion based magnetic tunnel junction neuron. We investigate how the electric field at the gate (pinning site), generated by the voltage signals from pre-neurons, modulates the domain wall motion, which reflects in the non-linear switching behaviour of neuron magnetization. For the implementation of synaptic weights, we propose 3-terminal MTJ with stochastic domain wall motion in the free layer. We incorporate intrinsic pinning effects by creating triangular notches on the sides of the free layer. The pinning of domain wall and intrinsic thermal noise of device lead to the stochastic behaviour of domain wall motion. The control of this stochasticity by the spin orbit torque is shown to realize the potentiation and depression of the synaptic weight. The micromagnetics and spin transport studies in synapse and neuron are carried out by developing a coupled micromagnetic Non-Equilibrium Green’s Function (<i>MuMag-NEGF</i>) model. The minimization of the writing current pulse width by leveraging the thermal noise and demagnetization energy is also presented. Finally, we discuss the implementation of digit recognition by the proposed system using a spike time dependent algorithm.

Domain-wall motion at an ultrahigh speed driven by spin–orbit torque in synthetic antiferromagnets

2018 ◽  
Vol 29 (17) ◽  
pp. 175404 ◽  
Author(s):  
Ziyang Yu ◽  
Yue Zhang ◽  
Zhenhua Zhang ◽  
Ming Cheng ◽  
Zhihong Lu ◽  
...  
Keyword(s):  
Domain Wall ◽  
Wall Motion ◽  
Domain Wall Motion ◽  
Spin Orbit
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