Spin-orbit torque–driven propagating spin waves

Spin-orbit torque (SOT) can drive sustained spin wave (SW) auto-oscillations in a class of emerging microwave devices known as spin Hall nano-oscillators (SHNOs), which have highly nonlinear properties governing robust mutual synchronization at frequencies directly amenable to high-speed neuromorphic computing. However, all demonstrations have relied on localized SW modes interacting through dipolar coupling and/or direct exchange. As nanomagnonics requires propagating SWs for data transfer and additional computational functionality can be achieved using SW interference, SOT-driven propagating SWs would be highly advantageous. Here, we demonstrate how perpendicular magnetic anisotropy can raise the frequency of SOT-driven auto-oscillations in magnetic nanoconstrictions well above the SW gap, resulting in the efficient generation of field and current tunable propagating SWs. Our demonstration greatly extends the functionality and design freedom of SHNOs, enabling long-range SOT-driven SW propagation for nanomagnonics, SW logic, and neuromorphic computing, directly compatible with CMOS technology.

Download Full-text

Model-Based Optimal Control for Underwater Robotics

Volume 3: 30th Computers and Information in Engineering Conference, Parts A and B ◽

10.1115/detc2010-29056 ◽

2010 ◽

Author(s):

Yingfeng Ji ◽

Ryoichi S. Amano ◽

Ronald A. Perez

Keyword(s):

High Speed ◽

Linear Control ◽

Design Stage ◽

Underwater Robotics ◽

Fluid Forces ◽

Nonlinear Properties ◽

Highly Nonlinear ◽

Control Technologies ◽

The One ◽

External Forces

It is always one of the most challenging problems to control an underwater robotics due to the complex external forces in an underwater environment. It is difficult to obtain an ideal control performance using linear control technologies due to highly nonlinear properties of system. A valid method of linearization for nonlinear system is provided in this study. Based on this linearized system, the linear control theories were therefore employed for the tracking control of underwater robotics. The panning and tilting motions of this underwater robotics can basically track two given sinusoidal references based on the simulation results. In order to achieve a high-speed manipulation of this underwater robotics, fluid forces have to be considered and modeled. A computational fluid dynamics (CFD) technology is adopted in order to obtain more precise hydrodynamic models for simulation at the design stage. Two torque models that represent the degree of freedoms (DOFs) of panning and tilting respectively have been developed using the CFD software. The dynamic model of this robotics used in this paper is the one by Ji, et al [1].

Download Full-text

Projected Performance of Sub-10 nm GaN-based Double Gate MOSFETs

Circulation in Computer Science ◽

10.22632/ccs-2017-251-50 ◽

2017 ◽

Vol 2 (2) ◽

pp. 15-19 ◽

Cited By ~ 3

Author(s):

Md. Saud Al Faisal ◽

Md. Rokib Hasan ◽

Marwan Hossain ◽

Mohammad Saiful Islam

Keyword(s):

High Speed ◽

Field Effect Transistors ◽

Cmos Technology ◽

Channel Length ◽

Capacitive Coupling ◽

Oxide Semiconductor ◽

Double Gate ◽

Short Channel ◽

Channel Effects ◽

Silvaco Atlas

GaN-based double gate metal-oxide semiconductor field-effect transistors (DG-MOSFETs) in sub-10 nm regime have been designed for the next generation logic applications. To rigorously evaluate the device performance, non-equilibrium Green’s function formalism are performed using SILVACO ATLAS. The device is turn on at gate voltage, VGS =1 V while it is going to off at VGS = 0 V. The ON-state and OFF-state drain currents are found as 12 mA/μm and ~10-8 A/μm, respectively at the drain voltage, VDS = 0.75 V. The sub-threshold slope (SS) and drain induced barrier lowering (DIBL) are ~69 mV/decade and ~43 mV/V, which are very compatible with the CMOS technology. To improve the figure of merits of the proposed device, source to gate (S-G) and gate to drain (G-D) distances are varied which is mentioned as underlap. The lengths are maintained equal for both sides of the gate. The SS and DIBL are decreased with increasing the underlap length (LUN). Though the source to drain resistance is increased for enhancing the channel length, the underlap architectures exhibit better performance due to reduced capacitive coupling between the contacts (S-G and G-D) which minimize the short channel effects. Therefore, the proposed GaN-based DG-MOSFETs as one of the excellent promising candidates to substitute currently used MOSFETs for future high speed applications.

Download Full-text

Spin–Orbit Torque‐Induced Domain Nucleation for Neuromorphic Computing

Advanced Materials ◽

10.1002/adma.202103672 ◽

2021 ◽

pp. 2103672

Author(s):

Jing Zhou ◽

Tieyang Zhao ◽

Xinyu Shu ◽

Liang Liu ◽

Weinan Lin ◽

...

Keyword(s):

Spin Orbit ◽

Neuromorphic Computing

Download Full-text

Materials Requirements of High-Speed and Low-Power Spin-Orbit-Torque Magnetic Random-Access Memory

2019 IEEE SOI-3D-Subthreshold Microelectronics Technology Unified Conference (S3S) ◽

10.1109/s3s46989.2019.9320730 ◽

2019 ◽

Author(s):

Xiang Li ◽

Shy-Jay Lin ◽

DC Mahendra ◽

Yu-Ching Liao ◽

Chengyang Yao ◽

...

Keyword(s):

Low Power ◽

High Speed ◽

Random Access ◽

Random Access Memory ◽

Spin Orbit ◽

Access Memory ◽

Magnetic Random Access Memory

Download Full-text

Neuro-Inspired Signal Processing in Ferromagnetic Nanofibers

Biomimetics ◽

10.3390/biomimetics6020032 ◽

2021 ◽

Vol 6 (2) ◽

pp. 32

Author(s):

Tomasz Blachowicz ◽

Jacek Grzybowski ◽

Pawel Steblinski ◽

Andrea Ehrmann

Keyword(s):

Data Processing ◽

Data Storage ◽

Domain Walls ◽

Data Transfer ◽

Synaptic Activity ◽

Neuromorphic Computing ◽

Rotating Magnetic Fields ◽

Micromagnetic Simulations ◽

Energy Consuming ◽

Stochastic Data

Computers nowadays have different components for data storage and data processing, making data transfer between these units a bottleneck for computing speed. Therefore, so-called cognitive (or neuromorphic) computing approaches try combining both these tasks, as is done in the human brain, to make computing faster and less energy-consuming. One possible method to prepare new hardware solutions for neuromorphic computing is given by nanofiber networks as they can be prepared by diverse methods, from lithography to electrospinning. Here, we show results of micromagnetic simulations of three coupled semicircle fibers in which domain walls are excited by rotating magnetic fields (inputs), leading to different output signals that can be used for stochastic data processing, mimicking biological synaptic activity and thus being suitable as artificial synapses in artificial neural networks.

Download Full-text

Dual-shot dynamics and ultimate frequency of all-optical magnetic recording on GdFeCo

Light Science & Applications ◽

10.1038/s41377-020-00451-z ◽

2021 ◽

Vol 10 (1) ◽

Author(s):

Sicong Wang ◽

Chen Wei ◽

Yuanhua Feng ◽

Hongkun Cao ◽

Wenzhe Li ◽

...

Keyword(s):

Magnetization Reversal ◽

Energy Efficient ◽

High Speed ◽

Data Transfer ◽

Laser Pulses ◽

Time Resolved ◽

All Optical ◽

Fs Laser ◽

High Speed Data ◽

Natural Way

AbstractAlthough photonics presents the fastest and most energy-efficient method of data transfer, magnetism still offers the cheapest and most natural way to store data. The ultrafast and energy-efficient optical control of magnetism is presently a missing technological link that prevents us from reaching the next evolution in information processing. The discovery of all-optical magnetization reversal in GdFeCo with the help of 100 fs laser pulses has further aroused intense interest in this compelling problem. Although the applicability of this approach to high-speed data processing depends vitally on the maximum repetition rate of the switching, the latter remains virtually unknown. Here we experimentally unveil the ultimate frequency of repetitive all-optical magnetization reversal through time-resolved studies of the dual-shot magnetization dynamics in Gd27Fe63.87Co9.13. Varying the intensities of the shots and the shot-to-shot separation, we reveal the conditions for ultrafast writing and the fastest possible restoration of magnetic bits. It is shown that although magnetic writing launched by the first shot is completed after 100 ps, a reliable rewriting of the bit by the second shot requires separating the shots by at least 300 ps. Using two shots partially overlapping in space and minimally separated by 300 ps, we demonstrate an approach for GHz magnetic writing that can be scaled down to sizes below the diffraction limit.

Download Full-text

The Demonstration of S2P (Serial-to-Parallel) Converter with Address Allocation Method Using 28 nm CMOS Technology

Applied Sciences ◽

10.3390/app11010429 ◽

2021 ◽

Vol 11 (1) ◽

pp. 429

Author(s):

Min-Su Kim ◽

Youngoo Yang ◽

Hyungmo Koo ◽

Hansik Oh

Keyword(s):

Integrated Circuits ◽

Embedded System ◽

Low Power ◽

High Speed ◽

Cmos Technology ◽

Clock Frequency ◽

Clock Generation ◽

Allocation Method ◽

Evaluation Board ◽

28 Nm

To improve the performance of analog, RF, and digital integrated circuits, the cutting-edge advanced CMOS technology has been widely utilized. We successfully designed and implemented a high-speed and low-power serial-to-parallel (S2P) converter for 5G applications based on the 28 nm CMOS technology. It can update data easily and quickly using the proposed address allocation method. To verify the performances, an embedded system (NI-FPGA) for fast clock generation on the evaluation board level was also used. The proposed S2P converter circuit shows extremely low power consumption of 28.1 uW at 0.91 V with a core die area of 60 × 60 μm2 and operates successfully over a wide clock frequency range from 5 M to 40 MHz.

Download Full-text

Investigation of PVT-Aware STT-MRAM Sensing Circuits for Low-VDD Scenario

Micromachines ◽

10.3390/mi12050551 ◽

2021 ◽

Vol 12 (5) ◽

pp. 551

Author(s):

Zhongjian Bian ◽

Xiaofeng Hong ◽

Yanan Guo ◽

Lirida Naviner ◽

Wei Ge ◽

...

Keyword(s):

Nonvolatile Memory ◽

High Speed ◽

Low Voltage ◽

Supply Voltage ◽

Random Access ◽

Magnetic Tunnel Junction ◽

Complementary Metal Oxide Semiconductor ◽

Current Mode ◽

Cmos Technology ◽

Oxide Semiconductor

Spintronic based embedded magnetic random access memory (eMRAM) is becoming a foundry validated solution for the next-generation nonvolatile memory applications. The hybrid complementary metal-oxide-semiconductor (CMOS)/magnetic tunnel junction (MTJ) integration has been selected as a proper candidate for energy harvesting, area-constraint and energy-efficiency Internet of Things (IoT) systems-on-chips. Multi-VDD (low supply voltage) techniques were adopted to minimize energy dissipation in MRAM, at the cost of reduced writing/sensing speed and margin. Meanwhile, yield can be severely affected due to variations in process parameters. In this work, we conduct a thorough analysis of MRAM sensing margin and yield. We propose a current-mode sensing amplifier (CSA) named 1D high-sensing 1D margin, high 1D speed and 1D stability (HMSS-SA) with reconfigured reference path and pre-charge transistor. Process-voltage-temperature (PVT) aware analysis is performed based on an MTJ compact model and an industrial 28 nm CMOS technology, explicitly considering low-voltage (0.7 V), low tunneling magnetoresistance (TMR) (50%) and high temperature (85 °C) scenario as the worst sensing case. A case study takes a brief look at sensing circuits, which is applied to in-memory bit-wise computing. Simulation results indicate that the proposed high-sensing margin, high speed and stability sensing-sensing amplifier (HMSS-SA) achieves remarkable performance up to 2.5 GHz sensing frequency. At 0.65 V supply voltage, it can achieve 1 GHz operation frequency with only 0.3% failure rate.

Download Full-text