Spintronic

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1 - Effects of electric field on magnetic properties of MnxGe1-xdocumentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} egin{document}$$Mn_{x}Ge_{1-x}$$end{document} diluted magnetic semiconductors
Gezahegn Assefa P. Singh

10.1007/s40094-015-0195-3

AbstractWe report the effect of external electric field (EEF) on the magnetic properties of MnxGe1-xdocumentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} أکثر

AbstractWe report the effect of external electric field (EEF) on the magnetic properties of MnxGe1-xdocumentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} egin{document}$$small {Mn_{x}Ge_{1-x}}$$end{document}, diluted magnetic semiconductor. We present a Kondo Lattice Model type Hamiltonian with exchange coupling between localized spins, itinerant holes and the EEF. The magnetization, the dispersion and critical temperature (Tcdocumentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} egin{document}$$T_{c}$$end{document}) are calculated for different values of EEF parameters (αdocumentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} egin{document}$$alpha$$end{document}) using double time temperature-dependent Green function formalism. The enhancement of the (Tcdocumentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} egin{document}$$T_{c}$$end{document}) with the EEF is shown to be very distinct and is in agreement with recent experimental observation and much required for spintronics applications and devices. تفاصيل المقالة

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2 - Investigating the effect of geometrical asymmetry on conductance and TMR ratio in the ZnO rock salt-based MTJ: a DFT study
Masoud Ansarino

10.1007/s40094-020-00380-7

AbstractEffects of geometrical asymmetry on spintronic properties of Fe/ZnO/Fe magnetic tunnel junction based on zinc oxide barrier tunnel with rock-salt crystalline structure is studied. Simulations are performed using density functional theory, and substituted layers أکثر

AbstractEffects of geometrical asymmetry on spintronic properties of Fe/ZnO/Fe magnetic tunnel junction based on zinc oxide barrier tunnel with rock-salt crystalline structure is studied. Simulations are performed using density functional theory, and substituted layers of C, Mg, Al, Mo, and Ta are used to make geometrically asymmetric structures. The results indicate that this asymmetry has a substantial influence on the properties of the spin-dependent electronic transport, conductance, and the tunneling magneto-resistance (TMR) ratio of the pristine symmetric structure. Additionally, it is shown that geometrical asymmetry results in a sharp decrease in the TMR ratio in one of these junctions and causes a negative TMR ratio in the other four asymmetric structures. Due to the large conductance of the three pristine, C and Al substituted structures in the PA configuration, these structures can be used to generate the current with pure spin for experimental purposes. تفاصيل المقالة

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3 - Density functional theory study on the effect of Cu- and Na-substituted layers on spin-dependent transport and TMR in the Fe/ZnO/Fe MTJ
Masoud Ansarino

10.1007/s40094-019-00346-4

AbstractUsing density functional theory, effects of Na- and Cu-substituted layers on the spin-dependent electronic transport properties of Fe/ZnO/Fe magnetic tunnel junction based on zinc oxide barrier tunnel, with rock-salt crystalline structure, have been studied. In أکثر

AbstractUsing density functional theory, effects of Na- and Cu-substituted layers on the spin-dependent electronic transport properties of Fe/ZnO/Fe magnetic tunnel junction based on zinc oxide barrier tunnel, with rock-salt crystalline structure, have been studied. In zero-bias voltage, conductance and tunneling magneto-resistance (TMR) ratio of structures are calculated. It is showed that substituted layers in the pristine junction greatly affect conductance and TMR ratio of this junction. The results indicated that Cu-substituted layer with reducing conductance of pristine structure in the antiparallel alignment configuration, and increasing its conductance in the parallel alignment, leads to a large TMR ratio, up to 1800%. Due to the large conductance of pristine and Cu-substituted devices in the parallel alignment, these structures would be very beneficial for experimental applications that require the spin-polarized current. تفاصيل المقالة

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4 - Effect of Li doping on the structural, electronic and magnetic properties of Mn(N, As)
Monir Kamalian Abdus Salam Sepahi Zeinab Moradi

10.22034/jna.2020.1912784.1235

In this study the effect of Li doping on the structural, electronic and magnetic properties of Mn(N, As) compounds was investigated using the Density Functional Theory (DFT) with the Quantum ESPRESSO software. The effect of the Li impurity on the Mn(N, As) conduction be أکثر

In this study the effect of Li doping on the structural, electronic and magnetic properties of Mn(N, As) compounds was investigated using the Density Functional Theory (DFT) with the Quantum ESPRESSO software. The effect of the Li impurity on the Mn(N, As) conduction behavior and physical characteristics such electronic band structure and density of states (DOS) was considered and discussed simultaneously. The obtained results demonstrated that after Li doping, the equilibrium lattice constant (a0) was decreased and the band gap energy was increased. The electronic band structure and density of states (DOS) of the MnN compound showed the metallic and anti-ferromagnetic characteristics while the MnAs compound exhibited the half-metallic and ferromagnetic properties however, by adding the Li impurity to these compounds, semiconducting and anti-ferromagnetic characteristics were observed. Moreover, the high spin configuration of the Mn atoms at thee DOS profiles revealed that these two anti-ferromagnetic compounds might also be promising candidates for future magneto-electronic and spintronic devices such as resonant tunneling magnetoresistance, ultrafast and ultrahigh-density spintronic devices. تفاصيل المقالة

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5 - Effect of Li doping on the structural, electronic, and magnetic properties of Mn(N, As)
Monir Kamalian Abdus Salam Sepahi Zeinab Moradi

10.22034/jna.2021.690108

In this study the effect of Li doping on the structural, electronic, and magneticproperties of Mn(N, As) compounds was investigated using the DensityFunctional Theory (DFT) with the Quantum ESPRESSO software. The effect of theLi impurity on the Mn(N, As) conduction beha أکثر

In this study the effect of Li doping on the structural, electronic, and magneticproperties of Mn(N, As) compounds was investigated using the DensityFunctional Theory (DFT) with the Quantum ESPRESSO software. The effect of theLi impurity on the Mn(N, As) conduction behavior and physical characteristicssuch electronic band structure and density of states (DOS) were consideredand discussed simultaneously. The obtained results demonstrated that afterLi doping, the equilibrium lattice constant (a0) was decreased and the bandgap energy was increased. The electronic band structure and density of states(DOS) of the MnN compound showed the metallic and anti-ferromagneticcharacteristics while the MnAs compound exhibited the half-metallic andferromagnetic properties, however, by adding the Li impurity to these compounds,semiconducting and anti-ferromagnetic characteristics were observed. Moreover,the high spin configuration of the Mn atoms at the DOS profiles revealed thatthese two anti-ferromagnetic compounds might also be promising candidatesfor future magneto-electronic and spintronic devices such as resonant tunnelingmagnetoresistance, ultrafast and ultrahigh-density spintronic devices. تفاصيل المقالة

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6 - طراحی یک سیستم محاسباتی نورومورفیک مبتنی بر اسپینترونیک با راندمان بالا با استفاده از مدار جانبی ردیابی جریان
پگاه شفقی هومان فرخانی مهدی دولتشاهی همایون مهدوی نسب

پیاده سازی یک سیستم محاسباتی عصبی (NCS) با استفاده از مدارهای دیجیتال و آنالوگ در فناوری نیم رسانای اکسید فلز مکمل (CMOS)، فضا و توان زیادی مصرف می کند. با پیشرفت تحقیقات نانو فناوری، ترکیب مدارهای اتصال تونلی مغناطیسی (MTJ) و CMOS، پیاده سازی NCSهایی با چگالی بالا ومصر أکثر

پیاده سازی یک سیستم محاسباتی عصبی (NCS) با استفاده از مدارهای دیجیتال و آنالوگ در فناوری نیم رسانای اکسید فلز مکمل (CMOS)، فضا و توان زیادی مصرف می کند. با پیشرفت تحقیقات نانو فناوری، ترکیب مدارهای اتصال تونلی مغناطیسی (MTJ) و CMOS، پیاده سازی NCSهایی با چگالی بالا ومصرف توان پایین را امکان پذیر کرده است. با این وجود، هنوز بین کارایی مغز انسان و NCSها فاصله زیادی وجود دارد. برای کاهش این شکاف، لازم است تا مصرف انرژی و تاخیر در NCS کاهش پیدا کند. مصرف انرژی زیاد NCS، به دلیل جریان زیاد مورد نیاز برای تغییر وضعیت MTJ است. در گذشته محققان با تکنیک های ردیابی ولتاژ MTJ و قطع جریان آن بلافاصله پس از کلیدزنی MTJ، مصرف انرژی را کاهش دادند. اما به دلیل تغییرات کوچک ولتاژ پس از کلیدزنی، در این روش ها مصرف انرژی همچنان بالا است (به دلیل نیاز به تقویت کننده ها).در این مقاله روش جدیدی مبتنی بر ردیابی جریان MTJ (به جای ولتاژ آن) و قطع جریان MTJ بلافاصله پس از کلیدزنی MTJ پیشنهاد شده است. با توجه به تغییرات زیاد در جریان MTJ پس از کلیدزنی (حدود 40 درصد)، نیازی به استفاده از تقویت کننده در مدار ردیابی و قطع جریان MTJ نیست. بنابراین، مدار ردیابی ولتاژ با مدار پیشنهادی جایگزین می‌شود تا مصرف انرژی، سرعت و تاخیر NCS بهبود یابد. در تمام طراحی های گذشته، تغییرات ولتاژ در دو سر MTJ PL, FL) یا هر دو( برای تشخیص کلیدزنی MTJ استفاده شده است. در مدار پیشنهادی کلیدزنی MTJ با توجه به جریان MTJ تشخیص داده می شود و سپس جریان آن بلافاصله قطع می‌شود. بر اساس نتایج شبیه‌سازی در فناوری 65nm-CMOS مدار پیشنهادی می‌تواند، مصرف انرژی و سرعت یک NCS را به ترتیب 49 درصد و 1/2/ برابر در مقایسه با یک NCS نوعی بهبود بخشد. تفاصيل المقالة

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