Artificial intelligence has become indispensable in modern life,but its energy consumption has become a significant concern due to its huge storage and computational demands.Artificial intelligence algorithms are main...Artificial intelligence has become indispensable in modern life,but its energy consumption has become a significant concern due to its huge storage and computational demands.Artificial intelligence algorithms are mainly based on deep learning algorithms,relying on the backpropagation of convolutional neural networks or binary neural networks.While these algorithms aim to simulate the learning process of the human brain,their low bio-fidelity and the separation of storage and computing units lead to significant energy consumption.The human brain is a remarkable computing machine with extraordinary capabilities for recognizing and processing complex information while consuming very low power.Tunneling magnetoresistance(TMR)-based devices,namely magnetic tunnel junctions(MTJs),have great advantages in simulating the behavior of biological synapses and neurons.This is not only because MTJs can simulate biological behavior such as spike-timing dependence plasticity and leaky integrate-fire,but also because MTJs have intrinsic stochastic and oscillatory properties.These characteristics improve MTJs’bio-fidelity and reduce their power consumption.MTJs also possess advantages such as ultrafast dynamics and non-volatile properties,making them widely utilized in the field of neuromorphic computing in recent years.We conducted a comprehensive review of the development history and underlying principles of TMR,including a detailed introduction to the material and magnetic properties of MTJs and their temperature dependence.We also explored various writing methods of MTJs and their potential applications.Furthermore,we provided a thorough analysis of the characteristics and potential applications of different types of MTJs for neuromorphic computing.TMR-based devices have demonstrated promising potential for broad application in neuromorphic computing,particularly in the development of spiking neural networks.Their ability to perform on-chip learning with ultra-low power consumption makes them an exciting prospect for future展开更多
Spintronics has received a great attention and significant interest within the past decades,and provided considerable and remarked applications in industry and electronic information etc.In spintronics,the MgO based m...Spintronics has received a great attention and significant interest within the past decades,and provided considerable and remarked applications in industry and electronic information etc.In spintronics,the MgO based magnetic tunnel junction(MTJ) is an important research advancement because of its physical properties and excellent performance,such as the high TMR ratio in MgO based MTJs.We present an overview of more than a decade development in MgO based MTJs.The review contains three main sections.(1) Research of several types of MgO based MTJs,including single-crystal MgO barrier based-MTJs,double barrier MTJs,MgO based MTJs with interlayer,novel electrode material MTJs based on MgO,novel barrier based MTJs,novel barrier MTJs based on MgO,and perpendicular MTJs.(2) Some typical physical effects in MgO based MTJs,which include six observed physical effects in MgO based MTJs,namely spin transfer torque(STT) effect,Coulomb blockade magnetoresistance(CBMR) effect,oscillatory magnetoresistance,quantum-well resonance tunneling effect,electric field assisted magnetization switching effect,and spincaloric effect.(3) In the last section,a brief introduction of some important device applications of MgO based MTJs,such as GMR & TMR read heads and magneto-sensitive sensors,both field and current switching MRAM,spin nano oscillators,and spin logic devices,have been provided.展开更多
联合战术信息分发系统(joint tactical information distribution system,JTIDS)采用软扩频、跳频、纠错编码相结合的抗干扰体制,具备很强的抗干扰能力。通过已公开的JTIDS技术体制,分析了JTIDS通信链路的数学模型,在此基础上,研究并得...联合战术信息分发系统(joint tactical information distribution system,JTIDS)采用软扩频、跳频、纠错编码相结合的抗干扰体制,具备很强的抗干扰能力。通过已公开的JTIDS技术体制,分析了JTIDS通信链路的数学模型,在此基础上,研究并得出了采用相干解调方式JTIDS数据链在高斯白噪声干扰和人为多音干扰条件下,经过莱斯衰落信道的符号错误概率(symbol error probability,SEP),根据理论结果进行计算,并由所得计算结果分析了干扰频率点数分布以及干扰频率偏移对于JTIDS传输性能的影响,为评估JTIDS通信网络在干扰环境下的效能提供基础。展开更多
We demonstrate in-plane field-free-switching spin-orbit torque(SOT)magnetic tunnel junction(MTJ)devices that are capable of low switching current density,fast speed,high reliability,and,most importantly,manufactured u...We demonstrate in-plane field-free-switching spin-orbit torque(SOT)magnetic tunnel junction(MTJ)devices that are capable of low switching current density,fast speed,high reliability,and,most importantly,manufactured uniformly by the 200-mm-wafer platform.The performance of the devices is systematically studied,including their magnetic properties,switch-ing behaviors,endurance and data retention.The successful integration of SOT devices within the 200-mm-wafer manufactur-ing platform provides a feasible way to industrialize SOT MRAMs.It is expected to obtain excellent performance of the devices by further optimizing the MTJ film stacks and the corresponding fabrication processes in the future.展开更多
The mechanism of perpendicular magnetic anisotropy（PMA）in a MgO-based magnetic tunnel junction（MTJ）has been studied in this article.By comparing the magnetic properties and elementary composition analysis for diff...The mechanism of perpendicular magnetic anisotropy（PMA）in a MgO-based magnetic tunnel junction（MTJ）has been studied in this article.By comparing the magnetic properties and elementary composition analysis for different CoFeB-based structures,such as Ta/CoFeB/MgO,Ta/CoFeB/Ta and Ru/CoFeB/MgO structures,it is found that a certain amount of Fe-oxide existing at the interface of CoFeB/MgO is helpful to enhance the PMA and the PMA is originated from the interface of CoFeB/MgO.In addition,Ta film plays an important role to enhance the PMA in Ta/CoFeB/MgO structure.展开更多
We have presented here a simple model of magnetic tunnel junction(MTJ)device and the proposed MTJ model is utilizedfor validation purpose and also to study its tunnel magneto-resistance(TMR)effect by both simulation a...We have presented here a simple model of magnetic tunnel junction(MTJ)device and the proposed MTJ model is utilizedfor validation purpose and also to study its tunnel magneto-resistance(TMR)effect by both simulation and experimentalmethod using an operational amplifier(OPAMP)based inverting amplifier.Experimental results substantiates both the simulatedand theoretical outcomes.展开更多
With the development of magnetic tunnel junction （MTJ） structure, it has been used in the field of electric circuit with emerging merits, such as high-density, easy integrated, etc. A novel register, in which MTJ de...With the development of magnetic tunnel junction （MTJ） structure, it has been used in the field of electric circuit with emerging merits, such as high-density, easy integrated, etc. A novel register, in which MTJ device is centered, is proposed in this paper. Based on the demand of MTJ＇s reading and writing process, some additional devices have been integrated with the MTJ device to compose the actual structure. It has been simulated using Hspice and the simulated result shows that it can be operated as a register in the circuit. Moreover, the layout of the register based on 0.5 μm complementary metal-oxide semiconductor （CMOS） process has been finished.展开更多
Nano-ring-type magnetic tunnel junctions （NR-MTJs） with the layer structure of Ta（5）/Ir22Mn78（10）/ Co75Fe25（2）/Ru（0.75）/CoooFe20B20（3）/Al（0.6）-oxide/Co60Fe20B20（2.5）/Ta（3）/Ru（5） （thickness unit：...Nano-ring-type magnetic tunnel junctions （NR-MTJs） with the layer structure of Ta（5）/Ir22Mn78（10）/ Co75Fe25（2）/Ru（0.75）/CoooFe20B20（3）/Al（0.6）-oxide/Co60Fe20B20（2.5）/Ta（3）/Ru（5） （thickness unit： nm） were nano-fabricated on the Si（100）/SiO2 substrate using magnetron sputtering deposition combined with the optical lithography, electron beam lithography （EBL） and Ar ion-beam etching techniques. The smaller NR-MTJs with the inner- and outer-diameter of around 50 and 100 nm and also their corresponding NR-MTJ arrays were nano-patterned. The tunnelling magnetoresistance （TMR ＆ R） versus driving current （I） loops for a spin-polarized current switching were measured, and the TMR ratio of around 35% at room temperature were observed. The critical values of switching current for the free Co60Fe20B20 layer relative to the reference Co6oFe2oB2o layer between parallel and anti-parallel magnetization states were between 0.50 and 0.75 mA in such NR-MTJs. It is suggested that the applicable MRAM fabrication with the density and capacity higher than 256 Mbit/inch2 even 6 Gbite/inch2 are possible using both I NR-MTJ＋1 transistor structure and current switching mechanism based on based on our fabricated 4×4 MRAM demo devices.展开更多
Spintronic devices are driving new paradigms of bio-inspired,energy efficient computation like neuromorphic stochastic computing and in-memory computing.They have also emerged as key candidates for non-volatile memori...Spintronic devices are driving new paradigms of bio-inspired,energy efficient computation like neuromorphic stochastic computing and in-memory computing.They have also emerged as key candidates for non-volatile memories for embedded systems as well as alternatives to persistent memories.To meet the growing demands from such diverse applications,there is need for innovation in materials and device designs which can be scaled and adapted according to the application.Two-dimensional(2D)magnetic materials address challenges facing bulk magnet systems by offering scalability while maintaining device integrity and allowing efficient control of magnetism.In this review,we highlight the progress made in experimental studies on 2D magnetic materials towards their integration into spintronic devices.We provide an account of the various relevant material discoveries,demonstrations of current and voltage-based control of magnetism and reported device systems,while also discussing the challenges and opportunities towards integration of 2D magnetic materials in commercial spintronic devices.展开更多
基金the National Key Research and Development Program of China(Grant Nos.2022YFB4400200 and 2022YFA1402604)the National Natural Science Foundation of China(Grant Nos.12104031 and 52121001)+2 种基金Science and Technology Major Project of Anhui Province(Grant No.202003a05020050)the International Collaboration Project B16001,the Beihang Hefei Innovation Research Institute Project BHKX-19-02,the China Postdoctoral Science Foundation No.2022M720345Outstanding Research Project of Shenyuan Honors College BUAA 230121102 for their financial support of this work.
文摘Artificial intelligence has become indispensable in modern life,but its energy consumption has become a significant concern due to its huge storage and computational demands.Artificial intelligence algorithms are mainly based on deep learning algorithms,relying on the backpropagation of convolutional neural networks or binary neural networks.While these algorithms aim to simulate the learning process of the human brain,their low bio-fidelity and the separation of storage and computing units lead to significant energy consumption.The human brain is a remarkable computing machine with extraordinary capabilities for recognizing and processing complex information while consuming very low power.Tunneling magnetoresistance(TMR)-based devices,namely magnetic tunnel junctions(MTJs),have great advantages in simulating the behavior of biological synapses and neurons.This is not only because MTJs can simulate biological behavior such as spike-timing dependence plasticity and leaky integrate-fire,but also because MTJs have intrinsic stochastic and oscillatory properties.These characteristics improve MTJs’bio-fidelity and reduce their power consumption.MTJs also possess advantages such as ultrafast dynamics and non-volatile properties,making them widely utilized in the field of neuromorphic computing in recent years.We conducted a comprehensive review of the development history and underlying principles of TMR,including a detailed introduction to the material and magnetic properties of MTJs and their temperature dependence.We also explored various writing methods of MTJs and their potential applications.Furthermore,we provided a thorough analysis of the characteristics and potential applications of different types of MTJs for neuromorphic computing.TMR-based devices have demonstrated promising potential for broad application in neuromorphic computing,particularly in the development of spiking neural networks.Their ability to perform on-chip learning with ultra-low power consumption makes them an exciting prospect for future
基金supported by the State Key Project of Fundamental Research of the Ministry of Science and Technology(Grant No. 2010CB934400)the National Natural Science Foundation of China (Grant Nos.10934099,51021061,and 11104338)+2 种基金the National Science Fund for Distinguished Young Scholars(Grant No.50325104)the International Collaborative Research Programs between NSFC and EPSRC of the United Kingdom(Grant No.10911130234)between NSFC and ANR of France(Grant No.F040803)
文摘Spintronics has received a great attention and significant interest within the past decades,and provided considerable and remarked applications in industry and electronic information etc.In spintronics,the MgO based magnetic tunnel junction(MTJ) is an important research advancement because of its physical properties and excellent performance,such as the high TMR ratio in MgO based MTJs.We present an overview of more than a decade development in MgO based MTJs.The review contains three main sections.(1) Research of several types of MgO based MTJs,including single-crystal MgO barrier based-MTJs,double barrier MTJs,MgO based MTJs with interlayer,novel electrode material MTJs based on MgO,novel barrier based MTJs,novel barrier MTJs based on MgO,and perpendicular MTJs.(2) Some typical physical effects in MgO based MTJs,which include six observed physical effects in MgO based MTJs,namely spin transfer torque(STT) effect,Coulomb blockade magnetoresistance(CBMR) effect,oscillatory magnetoresistance,quantum-well resonance tunneling effect,electric field assisted magnetization switching effect,and spincaloric effect.(3) In the last section,a brief introduction of some important device applications of MgO based MTJs,such as GMR & TMR read heads and magneto-sensitive sensors,both field and current switching MRAM,spin nano oscillators,and spin logic devices,have been provided.
文摘联合战术信息分发系统(joint tactical information distribution system,JTIDS)采用软扩频、跳频、纠错编码相结合的抗干扰体制,具备很强的抗干扰能力。通过已公开的JTIDS技术体制,分析了JTIDS通信链路的数学模型,在此基础上,研究并得出了采用相干解调方式JTIDS数据链在高斯白噪声干扰和人为多音干扰条件下,经过莱斯衰落信道的符号错误概率(symbol error probability,SEP),根据理论结果进行计算,并由所得计算结果分析了干扰频率点数分布以及干扰频率偏移对于JTIDS传输性能的影响,为评估JTIDS通信网络在干扰环境下的效能提供基础。
基金supported by the National Key Research and Development Program of China(Grant Nos.2021YFB3601303,2021YFB3601304,2021YFB3601300)National Natural Science Foundation of China(Nos.62001014 and 62171013)。
文摘We demonstrate in-plane field-free-switching spin-orbit torque(SOT)magnetic tunnel junction(MTJ)devices that are capable of low switching current density,fast speed,high reliability,and,most importantly,manufactured uniformly by the 200-mm-wafer platform.The performance of the devices is systematically studied,including their magnetic properties,switch-ing behaviors,endurance and data retention.The successful integration of SOT devices within the 200-mm-wafer manufactur-ing platform provides a feasible way to industrialize SOT MRAMs.It is expected to obtain excellent performance of the devices by further optimizing the MTJ film stacks and the corresponding fabrication processes in the future.
基金supported by the National Defense Advance Research Foundation(No.9140A08XXXXXX0DZ106)the Basic Research Program of Ministry of Education,China(No.JY10000925005)+2 种基金the Scientific Research Program Funded by Shaanxi Provincial Education Department(No.11JK0912)the Scientific Research Foundation of Xi’an University of Science and Technology(No.2010011)the Doctoral Research Startup Fund of Xi’an University of Science and Technology(No.2010QDJ029)
文摘The mechanism of perpendicular magnetic anisotropy（PMA）in a MgO-based magnetic tunnel junction（MTJ）has been studied in this article.By comparing the magnetic properties and elementary composition analysis for different CoFeB-based structures,such as Ta/CoFeB/MgO,Ta/CoFeB/Ta and Ru/CoFeB/MgO structures,it is found that a certain amount of Fe-oxide existing at the interface of CoFeB/MgO is helpful to enhance the PMA and the PMA is originated from the interface of CoFeB/MgO.In addition,Ta film plays an important role to enhance the PMA in Ta/CoFeB/MgO structure.
文摘We have presented here a simple model of magnetic tunnel junction(MTJ)device and the proposed MTJ model is utilizedfor validation purpose and also to study its tunnel magneto-resistance(TMR)effect by both simulation and experimentalmethod using an operational amplifier(OPAMP)based inverting amplifier.Experimental results substantiates both the simulatedand theoretical outcomes.
基金This work was supported in part by the open research fund of Key Laboratory of MEMS of Ministry of Education, Southeast University and the National Nature Science Foundation under Grant No.60876078, Funding Project for Academic Human Resources Development in Institutions of Higher Learning Under the Jurisdiction of Beijing Municipality （PHR（IHLB）） and Beijing Novel Research Star（2005B01）.
文摘With the development of magnetic tunnel junction （MTJ） structure, it has been used in the field of electric circuit with emerging merits, such as high-density, easy integrated, etc. A novel register, in which MTJ device is centered, is proposed in this paper. Based on the demand of MTJ＇s reading and writing process, some additional devices have been integrated with the MTJ device to compose the actual structure. It has been simulated using Hspice and the simulated result shows that it can be operated as a register in the circuit. Moreover, the layout of the register based on 0.5 μm complementary metal-oxide semiconductor （CMOS） process has been finished.
基金the State Key Project of Fundamental Research of Ministry of Science and Technology （No. 2006CB932200） the National Natural Science Foundation of China （NSFC, No. 10574156）+2 种基金 the Knowledge Innovation Program of Chinese Aca.demy of Sciencesthe protial support of 0utstanding Young Researcher Foundation （Nos. 50325104 and 50528101） K.C.Wong Education Foundation, Hong Kong.
文摘Nano-ring-type magnetic tunnel junctions （NR-MTJs） with the layer structure of Ta（5）/Ir22Mn78（10）/ Co75Fe25（2）/Ru（0.75）/CoooFe20B20（3）/Al（0.6）-oxide/Co60Fe20B20（2.5）/Ta（3）/Ru（5） （thickness unit： nm） were nano-fabricated on the Si（100）/SiO2 substrate using magnetron sputtering deposition combined with the optical lithography, electron beam lithography （EBL） and Ar ion-beam etching techniques. The smaller NR-MTJs with the inner- and outer-diameter of around 50 and 100 nm and also their corresponding NR-MTJ arrays were nano-patterned. The tunnelling magnetoresistance （TMR ＆ R） versus driving current （I） loops for a spin-polarized current switching were measured, and the TMR ratio of around 35% at room temperature were observed. The critical values of switching current for the free Co60Fe20B20 layer relative to the reference Co6oFe2oB2o layer between parallel and anti-parallel magnetization states were between 0.50 and 0.75 mA in such NR-MTJs. It is suggested that the applicable MRAM fabrication with the density and capacity higher than 256 Mbit/inch2 even 6 Gbite/inch2 are possible using both I NR-MTJ＋1 transistor structure and current switching mechanism based on based on our fabricated 4×4 MRAM demo devices.
文摘Spintronic devices are driving new paradigms of bio-inspired,energy efficient computation like neuromorphic stochastic computing and in-memory computing.They have also emerged as key candidates for non-volatile memories for embedded systems as well as alternatives to persistent memories.To meet the growing demands from such diverse applications,there is need for innovation in materials and device designs which can be scaled and adapted according to the application.Two-dimensional(2D)magnetic materials address challenges facing bulk magnet systems by offering scalability while maintaining device integrity and allowing efficient control of magnetism.In this review,we highlight the progress made in experimental studies on 2D magnetic materials towards their integration into spintronic devices.We provide an account of the various relevant material discoveries,demonstrations of current and voltage-based control of magnetism and reported device systems,while also discussing the challenges and opportunities towards integration of 2D magnetic materials in commercial spintronic devices.
