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Implementation of 16 Boolean logic operations based on one basic cell of spin-transfer-torque magnetic random access memory

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Science China(Information Sciences) 2023年第6期66卷 250-257页

作者： Yan HUANG Kaihua CAO Kun ZHANG Jinkai WANG Kewen SHI Zuolei HAO Wenlong CAI Ao DU Jialiang YIN Qing YANG Junfeng LI Jianfeng GAO Chao ZHAO Weisheng ZHAO Fert Beijing Institute MIIT Key Laboratory of SpintronicsSchool of Integrated Circuit Science and EngineeringBeihang University Institute of Microelectronics of the Chinese Academy of Sciences Beihang-Goertek Joint Microelectronics Institute Qingdao Research InstituteBeihang University

In-memory computing(IMC)systems based on emerging nonvolatile memories(NVMs)provide a thorough solution for memory wall issues and von Neumann bottlenecks. Massive IMC schemes have been proposed by utilizing ingenious structures and additional auxiliary components. However, these schemes are not compatible with the basic cell(one memory unit and one transistor)of emerging random-access memory(RAM), which goes against low-power and high-density requirements. In this paper, we propose a logic implementation scheme based on one magnetic tunnel junction and one transistor(1MTJ-1T), which is the basic cell of spin-transfer-torque magnetic RAM(STT-MRAM). With no other assistance, complete 16 logic operations can be accomplished in two steps with their logic outputs in-situ stored in the MTJ. The area(0.2 μm2)and energy consumption per logic operation(1.1–2.6 pJ)of the logic gates under 14 nm process node are evaluated using SPICE simulations, indicating its excellent performance. Our work exhibits a 1MTJ-1Tbased logic operation implementation, which can bridge the gap between STT-MRAM and high-performance IMC applications.

关键词： in-memory computing logic operation magnetic tunnel junctions transistor spin transfer torque

Electric and thermo spin transfer torques in Fe/Vacuum/Fe tunnel junction

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Frontiers of physics 2014年第6期9卷 768-773页

作者： Xing-Tao Jia Ke Xia Department of Physics Beijing Normal University Beijing 100875 China Department of Physics and Chemistry Henan Polytechnic University Jiaozuo 454000 China

We present first-principle calculations of electric and thermo spin transfer torques （STT） in Fe/Vacuum（Vac）/Fe magnetic tunnel junctions （MTJs）. Our quantitative studies demonstrate rich bias dependence of STT and tunnel inagneto resistance （TMR） behaviors with respect to the interface roughness. Thermoelectric effects in Fe/Vac/Fe MTJs is remarkable. We observe larger ZT of 6.2 in 8 ML clean Vacuum barrier, where responsible for. Thermo-STT in Fe/Vac/Fe with similar barrier thickness. the heavily restraitmd thermal conductance should be MTJs show same order as that in Fe/MgO/Fe MTJs with similar barrier thickness.

关键词： spin transfer torque Fe/Vacuum/Fe tunnel junction thermoelectric effect

Stateful implication logic based on perpendicular magnetic tunnel junctions

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Science China(Information Sciences) 2022年第2期65卷 197-203页

作者： Wenlong CAI Mengxing WANG Kaihua CAO Huaiwen YANG Shouzhong PENG Huisong LI Weisheng ZHAO Fert Beijing Institute MIIT Key Laboratory of Spintronics School of Integrated Circuit Science and EngineeringBeihang University Beihang-Goertek Joint Microelectronics Institute Qingdao Research Institute Beihang University

As the conventional von Neumann architecture meets critical limitations of data transfer bandwidth and energy consumption, perpendicular magnetic anisotropy magnetic tunnel junction based processing-in-memory paradigm attracts extensive attention as a promising substitute thanks to its nonvolatility, low-power switching, fast access and infinite endurance. In this work, we propose and experimentally demonstrate a new spintronic implication logic gate that consists of two parallel perpendicular magnetic anisotropy magnetic tunnel junctions with different diameters. Material implication and furthermore NAND logic functions are implemented by all electrically-controlled operations. The reliability of this structure is verified, especially in sub-20 nm node, which shows great potential for large-density processing-in-memory applications.

关键词： perpendicular magnetic anisotropy magnetic tunnel junction implication spin transfer torque spintronic implication logic gate processing-in-memory

Magnetization switching modes in nanopillar spin valve under the external field

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Science China(Physics,Mechanics & Astronomy) 2011年第7期54卷 1227-1234页

作者： HUANG HouBing MA XingQiao YUE Tao XIAO ZhiHua SHI SanQiang CHEN LongQing Department of Physics University of Science and Technology Beijing Beijing 100083 China Department of Materials Science and Engineering The Pennsylvania State University University Park PA 16802 USA Department of Mechanical Engineering The Hong Kong Polytechnic University Hung Horn Kowloon Hong Kong China

The current-induced magnetic switching is studied in Co/Cu/Co nanopillar with an in-plane magnetization traversed under the perpendicular-to-plane external *** switching is found to take place when the current density exceeds a *** analyzing precessional trajectories,evolutions of domain walls and magnetization switching times under the perpendicular magnetic field,there are two different magnetization switching modes:nucleation and domain wall motion reversal;uniform magnetization *** first mode occurs at lower current density,which is realized by the formation of the reversal nucleus and domain wall motion;while the second mode occurs through complete magnetization reversal at higher current ***,the switching time reduces as the spin-polarized current density increases,which can also be grouped into two reversal modes.

关键词： current-induced nanopiUar spin transfer torque magnetization switching domain wall motion reversal uniform mag-netization reversal

Simulation study of new 3-terminal devices for high speed STT-RAM

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Journal of Semiconductors 2011年第7期32卷 46-48页

作者：张树超胡江峰陈培毅邓宁 Institute of Microelectronics Tsinghua University Data Storage Institute A~*STAR

To improve the performance of spin transfer torque random access memory（STT-RAM）,especially writing speed,we propose three modified 3-terminal STT-RAM cells.A magnetic dynamic process in the new structures was investigated through micro-magnetic *** best switching speed of the new structures is 120%faster than that of the rectangular 3-terminal *** optimized 3-terminal device offers high speed while maintaining the high reliability of the 3-terminal structure.

关键词： spin transfer torque non-volatile memory spin valve micro-magnetic simulation

Symmetry ensemble theory of the spin wave emitting effect driven by current in nanoscale magnetic multilayers

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Chinese Physics B 2009年第5期18卷 2006-2011页

作者：任敏张磊胡九宁董浩邓宁陈培毅 Institute of Microelectronics Tsinghua UniversityTsinghua National Laboratory for Information Science and Technology

This paper proposes a symmetry ensemble model for the magnetic dynamics caused by spin transfer torque in nanoscale pseudo-spin-valves, in which individual spin moments in the free layer are considered as subsystems to form a spinor ensemble. The magnetization dynamics equation of the ensemble was developed. By analytically investigating the equation, many magnetization dynamics properties excited by polarized current reported in experiments, such as double spin wave modes and the abrupt frequency jump, can be successfully explained. It is pointed out that an external field is not necessary for spin wave emitting （SWE） and a novel perpendicular configuration structure can provide much higher SWE efficiency in zero magnetic field.

关键词： symmetry ensemble model spin wave emitting spin transfer torque nanoscale magneticmultilayer

Voltage control of magnetization switching and dynamics

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Chinese Physics B 2018年第6期27卷 443-447页

作者： Hong-Yu Wen Jian-Bai Xia The State Key Laboratory of Superlattices and Microstructures Institute of Semiconductors Chinese Academy of Sciences Beijing 100083 China

The voltage controlled magnetic switching effect is verified experimentally. The Landau–Lifshitz–Gilbert（LLG）equation is used to study the voltage controlled magnetic switching. It is found that the initial values of magnetic moment components are critical for the switching effect, which should satisfy a definite condition. The external magnetic field which affects only the oscillation period should be comparable to the internal magnetic field. If the external magnetic field is too small, the switching effect will disappear. The precessions of mx and my are the best for the tilt angle of the external magnetic field θt = 0？, i.e., the field is perpendicular to the sample plane.

关键词： magnetic switching voltage control spin transfer torque Landau-Lifshitz-Gilbert (LLG) equa- tion

Control of spins in a nano-sized magnet using electric-current

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Chinese Physics B 2017年第4期26卷 457-461页

作者：文宏玉夏建白 The State Key Laboratory of Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China

With the development of spintronics,spin-transfer torque control of magnetic properties receives considerable *** this paper the Landau-Lifshitz-Gilbert equation including the torque term is used to investigate the magnetic moment dynamics in the free layer of the ferromagnet/non-magnetic/ferromagnet（FM1/N/FM2） *** is found that the reverse critical time τ_c decreases with the current *** critical time τ_c as a function of current for the perpendicular and parallel easy magnetic axes are the *** critical time τ_c increases with the damping factor α *** the case of large current the influence of the damping factor α is smaller,but in the case of little torque the critical time τ_c increases greatly with the damping *** direction of the magnetization in the fixed layer influences the critical time,when the angle between the magnetization and the z direction changes from 0.1π to 0.4π,the critical time τ_c decreases from 26.7 to 15.6.

关键词： magnetization switching spin transfer torque Landau-Lifshitz-Gilbert (LLG) equation

spin transport in a Zigzag normal/ferromagnetic graphene junction

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Chinese Physics B 2015年第5期24卷 514-518页

作者：史豪晟 Vahram L.Grigoryan Department of Physics and State Key Laboratory of Surface Physics Fudan University

We study magnetic proximity effect induced low-energy spin transport in the normal/ferromagnetic junction of a semi-infinite zigzag graphene nanoribbon. Due to the absence of a spin flip in a single interface, the spin transfer in this model can be described by the ＂two-spin channel＂ model. We identify each spin channel as either a perfect conducting or a non-conducting channel. This feature leads to spin filter in symmetric zigzag graphene nanoribbon and spin precession in antisymmetric zigzag graphene nanoribbon, and helps to directly determine the exchange-splitting intensity directly, even without an external auxiliary bias.

关键词： graphene junction spin filter spin transfer torque magnetic proximity effect