Magnetoelectric domain wall dynamics and its implications for magnetoelectric memory

Domain wall dynamics in a magnetoelectric antiferromagnet is analyzed, and its implications for magnetoelectric memory applications are discussed. Cr2O3 is used in the estimates of the materials parameters. It is found that the domain wall mobility has a maximum as a function of the electric field due to the gyrotropic coupling induced by it. In Cr2O3, the maximal mobility of 0.1 m/(s Oe) is reached at E = 0.06 V/nm. Fields of this order may be too weak to overcome the intrinsic depinning field, which is estimated for B-doped Cr2O3. These major drawbacks for device implementation can be overcome by applying a small in-plane shear strain, which blocks the domain wall precession. Domain wall mobility of about 0.7 m/(s Oe) can then be achieved at E = 0.2 V/nm. A split-gate scheme is proposed for the domain-wall controlled bit element; its extension to multiple-gate linear arrays can offer advantages in memory density, programmability, and logic functionality

Magnetoelectric domain wall dynamics and its implications for magnetoelectric memory

Domain wall dynamics in a magnetoelectric antiferromagnet is analyzed, and its implications for magnetoelectric memory applications are discussed. Cr2O3 is used in the estimates of the materials parameters. It is found that the domain wall mobility has a maximum as a function of the electric field due to the gyrotropic coupling induced by it. In Cr2O3, the maximal mobility of 0.1 m/(s Oe) is reached at E = 0.06 V/nm. Fields of this order may be too weak to overcome the intrinsic depinning field, which is estimated for B-doped Cr2O3. These major drawbacks for device implementation can be overcome by applying a small in-plane shear strain, which blocks the domain wall precession. Domain wall mobility of about 0.7 m/(s Oe) can then be achieved at E = 0.2 V/nm. A split-gate scheme is proposed for the domain-wall controlled bit element; its extension to multiple-gate linear arrays can offer advantages in memory density, programmability, and logic functionality

MAGNETOELECTRIC MEMORY CELLS WITH DOMAIN-WALL-MEDIATED SWITCHING

A magnetoelectric memory cell with domain - wall - mediated switching is implemented using a split gate architecture . The split gate architecture allows a domain wall to be trapped within a magnetoelectric antiferromagnetic ( MEAF ) active layer . An extension of this architecture applies to multiple gate linear arrays that can offer advantages in memory density , programmability , and logic functionality . Applying a small anisotropic in - plane shear strain to the MEAF can block domain wall precession to improve reliability and speed of switchin

Plasticity of anchors in damaged by earthquake concrete base

Most frequently used types of anchors were subjected to experimental studies to obtain valid data on post-installed anchors, such as mechanical anchors (wedge expansion anchors, undercut anchors); bonded anchors (with epoxy resin) and bent cast-in-place anchors. The authors studied the effect of an earthquake-induced damage (plastic deformation) of a concrete base and multi-cyclic dynamic loads, similar to seismic ones, on plasticity of anchors. Plastic phase deformation in case of reinforced concrete base was simulated as a system of cracks of different opening width. The results of the research show that increase in the width of the crack opening from 1.5 to 3.0 mm leads to a decrease in the values of the plasticity factors. Dynamic loading does not lead to a significant change in the plasticity factor related to static loading for all failure mechanisms, except for the bond failure. On the base of obtained results reduction factors of seismic loads may be determined for further calculation of anchor joints subjected to seismic impact

Stability of skyrmion lattices and symmetries of quasi-two-dimensional chiral magnets

Recently there has been substantial interest in realizations of skyrmions, in particular in quasi-two-dimensional (2D) systems due to increased stability resulting from reduced dimensionality. A stable skyrmion, representing the smallest realizable magnetic texture, could be an ideal element for ultradense magnetic memories. Here we use the most general form of the quasi-2D free energy with Dzyaloshinskii-Moriya interactions constructed from general symmetry considerations reflecting the underlying system. We predict that the skyrmion phase is robust and it is present even when the system lacks the in-plane rotational symmetry. In fact, the lowered symmetry leads to increased stability of vortex-antivortex lattices with fourfold symmetry and in-plane spirals, in some instances even in the absence of an external magnetic field. Our results relate different hexagonal and square cell phases to the symmetries of materials used for realizations of skyrmions. This will give clear directions for experimental realizations of hexagonal and square cell phases, and will allow engineering of skyrmions with unusual properties. We also predict striking differences in gyrodynamics induced by spin currents for isolated skyrmions and for crystals where spin currents can be induced by charge carriers or by thermal magnons. We find that under certain conditions, isolated skyrmions can move along the current without a side motion which can have implications for realizations of magnetic memories

DUALISTIC LEGAL REGULATION OF ACQUIRED SUBJECTIVE HUMAN RIGHTS IN THE RUSSIAN FEDERATION

Purpose of the study: This article analyzes dualistic approaches to the determination of legal facts that grant citizens of the Russian Federation subjective rights. It is obvious that the concept of birth is still not specified in the existing Russian legislation. Different norms of the modern Russian legislation associate the legal fact of birth with the criterion of live birth. An embryo (fetus) cannot have a complex of general civil rights until the time of live birth. Methodology: The authors of the article have compared this constitutional directive with existing rules of other branches of Russian law and revealed a completely opposite situation. Main Findings: Of course, the existing discrepancies in certain legal acts that regulate the same or related social relations represent a classical legal conflict. Moreover, partial contradictions in the Russian legal system are caused by the fact that many sectoral norms conflict with the Constitution. Novelty/Originality: Legal certainty is a basic and system-forming principle that dialectically complements and develops other general-legal, intersectoral and sectoral principles, justifies their functional necessity, determines the accuracy and clarity of legal instructions, established order and limits their actions

Розробка способу відновлення ефективності плівкових СЕ ITO/CdS/CdTe/Cu/Au після деградації

A study into the influence of direct polarity on the output parameters of ITO/CdS/CdTe/Cu/Au solar cells (SC) has been conducted. We have experimentally registered the effect of an electric field of direct polarity on the output parameters and light diode characteristics of ITO/CdS/CdTe/Cu/Au SCs, which underwent a degradation of efficiency. When a shaded SE is exposed for not less than 120 minutes to the electric field, induced by an external DC voltage of magnitude (0.5‒0.9) V, whose polarity corresponds to the forward bias of n-p heterojunction, there is an increase in efficiency coefficient. This becomes possible if, during degradation of the instrument structure, such defects did not have time to develop, which, over the specified time of exposure, lead to resettable alternating electric microbreakdowns. It has been established that an increase in efficiency coefficient comes at the expense of the increased density of a photocurrent, decreased sequential and increased shunt resistances of SC. Improvement of diode characteristics occurs due to several physical processes. When a SC is fed a forward bias voltage, an electric field forms inside the diode structure of SC, which amplifies the built-in electric field of the rear р-р+ heterojunction and suppresses the built-in electric field of the frontal n+-p heterojunction. That occurs because the diodes are turned on towards each other. The magnitude of a forward bias voltage must not exceed the height of the potential barrier in a heterojunction. In this case, at the rear р-р+ heterojunction and in its adjoining areas from both sides the processes will be intensified that are associated with the transport of copper atoms, the restructuring of complexes of point defects containing copper, and the phase transformations of Cu1,4Te into Cu2-xTe. In addition, under the influence of the field induced by a forward bias voltage, the CuCd- particles from the depletion area of a CdS layer will start moving towards the absorber. That should reduce the resistance part of the CdS layer and lead to a decrease in the depletion area width from the absorber's side, thereby increasing the spectral sensitivity of SC in the shortwave and medium-wave fields of solar spectrum. Electrodiffusion of additional amount of CuCd- to the absorber must enhance the above-described and related effect of the increased spectral sensitivity and thus Jph of instruments. Based on the conducted research, we have constructed an algorithm for restoring the efficiency of ITO/CdS/CdTe/Cu/Au SCs and for rejecting the irrevocably degraded instrumental structures included in a running moduleПроведено исследование влияния прямой полярности на выходные параметры солнечных элементов (СЭ) ITO/CdS/CdTe/Cu/Au. Экспериментально зафиксировано влияние электрического поля прямой полярности на выходные параметры и световые диодные характеристики СЭ ITO/CdS/CdTe/Cu/Au, в которых произошла деградация КПД. При выдержке затемненного СЭ, не менее 120 минут в электрическом поле, приведенным внешним постоянным напряжением величиной (0,5-0,9) В, полярность которого соответствует прямому смещению n-p гетероперехода, наблюдается рост КПД. Это возможно, если при деградации приборной структуры не успели сформироваться дефекты, которые за указанное время выдержки приводят к чередующимся самовосстанавливающимся электрическим микропробоям. Установлено, что рост КПД происходит за счет увеличения плотности фототока, уменьшения последовательного и увеличения шунтирующего сопротивлений СЭ. Улучшение диодных характеристик происходит благодаря нескольким физическим процессам. При подаче на СЭ напряжения прямого смещения, внутри диодной структуры СЭ создается электрическое поле, которое усиливает встроенное электрическое поле тыльного р-р+ гетероперехода и подавляет встроенное электрическое поле фронтального n+-p гетероперехода. Это происходит вследствие того, что диоды включены на встречу друг другу. Величина напряжения прямого смещения не должна превышать высоту потенциального барьера гетероперехода. В этом случае на тыльном р-р+ гетеропереходе и в прилегающих к нему с обеих сторон областях будут интенсифицированы процессы, связанные с транспортом атомов меди, перестройкой комплексов точечных дефектов, содержащих медь, и с фазовыми превращениями Cu1,4Te в Cu2-xTe. Также под влиянием поля, индуцированного напряжением прямого смещения, частицы CuCd-из области обеднения слоя CdS начнут двигаться в абсорбер. Это должно снизить сопротивление части слоя CdS и привести к уменьшению ширины области обеднения со стороны абсорбера, повысив, тем самым, спектральную чувствительность СЕ в коротковолновой и средневолновой областях солнечного спектра. Электродиффузия дополнительного количества CuCd- в абсорбер должна усиливать вышеописанный и связанный с этим эффект повышения спектральной чувствительности, а значит и Jф приборов. На основе проведенных исследований был разработан алгоритм восстановления эффективности СЭ ITO/CdS/CdTe/Cu/Au и отбраковки безвозвратно деградированных приборных структур в составе работающего модуляПроведено дослідження впливу прямої полярності на вихідні параметри сонячних елементів (СЕ) ITO/CdS/CdTe/Cu/Au. Експериментально зафіксовано вплив електричного поля прямої полярності на вихідні параметри і світлові діодні характеристики СЕ ITO/CdS/CdTe/Cu/Au, у яких відбулася деградація ККД. При витримці затемненого СЕ не менше 120 хвилин в електричному полі, наведеним зовнішньою постійною напругою величиною (0,5–0,9) В, спостерігається зростання ККД. Полярність електричного поля повинна відповідати прямому зміщенню n-p гетеропереходу. Зростання ККД спостерігається лише у тому випадку, якщо при деградації приладової структури не встигли сформуватися дефекти, які за вказаний час витримки призводять до самовідновлюючих електричних мікропробоїв, що чередуються.Встановлено що зростання ККД відбувається за рахунок збільшення густин фотоструму, зменшення послідовного та збільшення шунтувального опорів СЕ. Покращення діодних характеристик відбувається завдяки кільком фізичним процесам. При подачі на СЕ напруги прямого зміщення, всередині диодной структури СЕ створюється електричне поле, яке підсилює вбудоване електричне поле тильного р–р + гетероперехода і пригнічує вбудоване електричне поле фронтального n+–p гетероперехода. Це відбувається внаслідок того, що діоди включені на зустріч один одному. Величина напруги прямого зміщення не повинна перевищувати висоту потенційного бар'єру гетеропереходу. У цьому випадку на тильному р-р+ гетеропереході та у прилеглих до нього з обох сторін областях будуть інтенсифіковані процеси пов’язані з транспортом атомів міді. Крім того спостерігається перебудова комплексів точкових дефектів, що містять мідь, та фазові перетвореннями Cu1,4Te в Cu2-xTe.Також під впливом поля, індукованого прямозміщуючою напругою, частки CuCd- з області збіднення шару CdS почнуть рухатись у абсорбер. Це повинно знизити опір частини шару CdS і привести до зменшення ширини області збідніння з боку абсорбера, тим самим, забезпечити зростання спектральної чутливості СЕ в короткохвильовій і середньохвильовій областях сонячного спектру. Електродифузія додаткової кількості CuCd- в абсорбер повинна посилювати вищеописаний і пов'язаний з цим ефект підвищення спектральної чутливості, а значить і Jф приладів. На основі проведених досліджень був розроблений алгоритм відновлення ефективності СЕ ITO/CdS/CdTe/Cu/Au і відбраковування деградованих приладових структур в складі працюючого модуля що працю

New naphtho[1,8-ef]perimidines: synthesis, fluorescence studies and application for detection of nitroanalytes

A rational approach to the synthesis of substituted naphtho[1,8-ef]perimidines based on SNH methodology and cyclization  reaction in the series of condensed azines with naphthalene substituents was presented. Photophysical properties of the obtained fluorophores were studied, in particular, green fluorescence in the 485–536 nm range with quantum yield up to 32.4% was detected. HOMO-LUMO energy values and distributions for the new compounds were calculated by the DFT method in comparison with nitroanalytes and perylene. Based on the data obtained, as well as on the results of fluorescence titration, the possibility of using the new diazaperylenes as potential chemosensors for the visual detection of nitro-containing explosives was shown

THE SHAPED CHARGE JET INTERACTION WITH FINITE THICKNESS TARGETS

Abstract --The problem of reducing the jet penetration capability upon its interaction with the finite-thickness target, due to the erosion of the front region of the jet having perforated through the target, is considered. The experimental examination and the mathematical modeling of the process were performed; semi-empirical formulas were obtained. The calculation techniques are shown to allow the description of interaction processes with satisfactory accuracy