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We observe a strong thermally controlled magnon-mediated interlayer coupling of two ferromagnetic layers via an antiferromagnetic spacer in spin-valve type trilayers. The effect manifests itself as a coherent switching as well as collective resonant precession of the two ferromagnets, which can be controlled by varying temperature and the spacer thickness. We explain the observed behavior as due to a strong hybridization of the ferro- and antiferromagnetic magnon modes in the trilayer at temperatures just below the Neel temperature of the antiferromagnetic spacer., QC 20210728

We investigate the role of domain walls in the ultrafast magnon dynamics of an antiferromagnetic NiO single crystal in a pump-probe experiment with variable pump photon energy. Analyzing the amplitude of the energy-dependent photoinduced ultrafast spin dynamics, we detect a yet unreported coupling between the material's characteristic terahertz- and gigahertz-magnon modes. We explain this unexpected coupling between two orthogonal eigenstates of the corresponding Hamiltonian by modeling the magnetoelastic interaction between spins in different domains. We find that such interaction, in the nonlinear regime, couples the two different magnon modes via the domain walls and it can be optically exploited via the exciton-magnon resonance.

Contains fulltext : 206090.pdf (publisher's version ) (Open Access)

In this work we focus on magnetic relaxation in Mn80Ir20(12 nm)/Cu(6 nm)/Py(dF) antiferromagnet/Cu/ferromagnet (AFM/Cu/FM) multilayers with different thickness of the ferromagnetic permalloy layer. An effective FM-AFM interaction mediated via the conduction electrons in the nonmagnetic Cu spacer - the spin-pumping effect - is detected as an increase in the linewidth of the ferromagnetic resonance (FMR) spectra and a shift of the resonant magnetic field. We further find experimentally that the spin-pumping-induced contribution to the linewidth is inversely proportional to the thickness of the Py layer. We show that this thickness dependence likely originates from the dissipative dynamics of the free and localized spins in the AFM layer. The results obtained could be used for tailoring the dissipative properties of spintronic devices incorporating antiferromagnetic layers., QC 20170522

We study current-driven skyrmion motion in uniaxial thin film antiferromagnets in the presence of the Dzyaloshinskii–Moriya interactions and in an external magnetic field. We phenomenologically include relaxation and current-induced torques due to both spin–orbit coupling and spatially inhomogeneous magnetic textures in the equation for the Néel vector of the antiferromagnet. Using the collective coordinate approach we apply the theory to a two-dimensional antiferromagnetic skyrmion and estimate the skyrmion velocity under an applied DC electric current.

Вперше на основі загальних принципів магнітної динаміки та законів збереження доведена можливість передачі спінового крутильного моменту антиферомагнітним матеріалам. Розраховано спектри спінових збуджень та амплітудно-частотні характеристики різних магнітих систем зі складною структурою в присутності спін-поляризованого струму. Показано, що індукований спін-поляризованим струмом рух магнітних моментів призводить до виникнення макроскопічної намагніченості АФМ прошарку. Запропоновано метод вимірювання ефектів спін-поляризованого струму в АФМ матеріалах за допомогою ефекту магнітоопору, який виникає за рахунок динамічної макроскопічної намагніченості. Вперше здійснено узагальнення теорії Браунівського руху АФМ вектора для АФМ наночастинки і отримані кінетичні рівняння для опису динаміки колінеарного антиферомагнетика в присутності шумів, розроблено методи його розв’язку врізних режимах: докритичному (поблизу положення рівноваги) та надкритичному (в околі режиму генерації). Розроблено теорію для опису магнітної динаміки антиферомагнітних текстур в присутності струму високої густини і на її основі досліджено можливість керування рухом доменної стінки за допомогою електричного струму. Досліджено динаміку наноелектромеханічної системи з антиферомагнітним прошарком в присутності спін-поляризованого струму. Передбачено спін-діодний ефект, який полягає у випрямленні змінного струму за рахунок коливань магнітоопору, обумовлених спін-поляризованим струмом. Досліджено поведінку магнітної структури аморфних дротів під дією змінного струму, зовнішнього магнітного поля та механічних напруг. Виявлено фізичний механізм, що відповідає за спостережувальне зміщення величини поля стрибка магнітоопору під дією зовнішніх механічних напруг. Вперше побудовано модель для опису ефектів форми в АФМ i досліджено ефекти форми в синтетичних структурах з АФМ прошарками, зокрема в мультифероїках двох типів: АФМ/фероелектрик і АФМ/феромагнетик. На основі розвинутих моделей розроблено метод оптималь, Starting from general principles of magnetic dynamics and laws of conservation we demonstrated a possibility of spin torque transfer in antiferromagnetic materials. We calculated the spectra and amplitude-frequency characteristics of spin excitations for different types of magnetic systems with complex structure in presence of spin – polarized current. It is shown that spin-polarized current induces motion of magnetic moments and appearance of macroscopic magnetization of an AFM layer. We propose new method of measurement of spintronic effects in AFM materials with help of effect of magnetoresistance which arises due to dynamic macroscopic magnetization. We generalized the Brownian theory for the motion of AFM-vector in AFM nanoparticle and derived the kinetic equations for the description of magnetic dynamics for collinear antiferromagnet in the presence of noise. We also developed the methods for its solution in different regimes: precritical (close to equilibrium) and supercritical (in the vicinity stationary rotation). We developed the theory for description of magnetic dynamics of antiferromagnetic textures in the presence of high density current and demonstrated the possibility to control the domain-wall motion with the help of electric current. Dynamics of nanoelectromechanical system with an antiferromagnetic layer in the oresence of spin-polarized current was also studied. We predicted the spin-diode effect in antiferromagnetic systems which consists in rectification of alternating current at the expense of current-induced magnetoresistance oscillations. We studied the current-induced behavior of the magnetic structure in the amorphous wires in the presence of the external magnetic field, and mechanical stresses and revealed underlying physical mechanism responsible for a jump of magnetoresistance under external mechanical stresses. We developed a model that describes shape effects in antiferromagnetic nanoparticles and synthetic multiferroics, in particula, Впервые на основе общих принципов магнитной динамики и законов сохранения доказана возможность передачи спинового крутящего момента антиферромагнитным материалам. Рассчитано спектры спиновых возбуждений и амплитудно - частотные характеристики различных магнитах систем со сложной структурой в присутствии спин - поляризованного тока. Показано , что индуцированный спин - поляризованным током движение магнитных моментов приводит к возникновению макроскопической намагниченности АФМ слоя. Предложен метод измерения эффектов спин - поляризованного тока в АФМ материалах с помощью эффекта магнитосопротивления , который возникает за счет динамической макроскопической намагниченности . Впервые осуществлено обобщение теории Брауновский движения АФМ вектора для АФМ наночастицы и полученные кинетические уравнения для описания динамики коллинеарных антиферромагнетика в присутствии шумов , разработаны методы его решения в различных режимах: докритическом ( вблизи положения равновесия) и сверхкритическом ( в окрестности режима генерации ) . Разработана теория для описания магнитной динамики антиферромагнитных текстур в присутствии тока высокой плотности и на ее основе исследована возможность управления движением доменной стенки с помощью электрического тока. Исследована динамика наноэлектромеханические системы с антиферромагнитным прослойкой в присутствии спин - поляризованного тока. Предусмотрено спин - диодный эффект , который заключается в выпрямлении переменного тока за счет колебаний магнитосопротивления , обусловленных спин - поляризованным током. Исследовано поведение магнитной структуры аморфных проводов под действием переменного тока , внешнего магнитного поля и механических напряжений. Выявлено физический механизм , отвечающий за наблюдательный смещение величины поля скачка магнитосопротивления под действием внешних механических напряжений. Впервые построена модель для описания эффектов формы в АФМ i исследованы эффекты формы в синтетических структурах с АФМ слоями , в част

We demonstrate the possibility to drive an antiferromagnetic domain wall at high velocities by fieldlike Néel spin-orbit torques. Such torques arise from current-induced local fields that alternate their orientation on each sublattice of the antiferromagnet and whose orientation depends primarily on the current direction, giving them their fieldlike character. The domain wall velocities that can be achieved by this mechanism are 2 orders of magnitude greater than the ones in ferromagnets. This arises from the efficiency of the staggered spin-orbit fields to couple to the order parameter and from the exchange-enhanced phenomena in antiferromagnetic texture dynamics, which leads to a low domain wall effective mass and the absence of a Walker breakdown limit. In addition, because of its nature, the staggered spin-orbit field can lift the degeneracy between two 180° rotated states in a collinear antiferromagnet, and it provides a force that can move such walls and control the switching of the states.

Antiferromagnetic spintronics is an emerging research field whose focus is on the electrical, optical or other means of control of the antiferromagnetic order parameter and its utility in information technology devices. An example of recently discovered new concepts is the Néel spin-orbit torque which allows for the antiferromagnetic order parameter to be controlled by an electrical current in common microelectronic circuits. In this review we discuss the utility of antiferromagnets as active and supporting materials for spintronics, the interplay of antiferromagnetic spintronics with other modern research fields in condensed matter physics, and its utility in future "More than Moore" information technologies.

Antiferromagnetic spintronics is an emerging research field whose focus is on the electrical, optical or other means of control of the antiferromagnetic order parameter and its utility in information technology devices. An example of recently discovered new concepts is the Néel spin-orbit torque which allows for the antiferromagnetic order parameter to be controlled by an electrical current in common microelectronic circuits. In this review we discuss the utility of antiferromagnets as active and supporting materials for spintronics, the interplay of antiferromagnetic spintronics with other modern research fields in condensed matter physics, and its utility in future "More than Moore" information technologies.

We demonstrate the possibility to drive an antiferromagnetic domain wall at high velocities by fieldlike Néel spin-orbit torques. Such torques arise from current-induced local fields that alternate their orientation on each sublattice of the antiferromagnet and whose orientation depends primarily on the current direction, giving them their fieldlike character. The domain wall velocities that can be achieved by this mechanism are 2 orders of magnitude greater than the ones in ferromagnets. This arises from the efficiency of the staggered spin-orbit fields to couple to the order parameter and from the exchange-enhanced phenomena in antiferromagnetic texture dynamics, which leads to a low domain wall effective mass and the absence of a Walker breakdown limit. In addition, because of its nature, the staggered spin-orbit field can lift the degeneracy between two 180° rotated states in a collinear antiferromagnet, and it provides a force that can move such walls and control the switching of the states.

Antiferromagnetic spintronics is an emerging research field whose focus is on the electrical, optical or other means of control of the antiferromagnetic order parameter and its utility in information technology devices. An example of recently discovered new concepts is the Néel spin-orbit torque which allows for the antiferromagnetic order parameter to be controlled by an electrical current in common microelectronic circuits. In this review we discuss the utility of antiferromagnets as active and supporting materials for spintronics, the interplay of antiferromagnetic spintronics with other modern research fields in condensed matter physics, and its utility in future "More than Moore" information technologies.

Antiferromagnetic spintronics is an emerging research field whose focus is on the electrical, optical or other means of control of the antiferromagnetic order parameter and its utility in information technology devices. An example of recently discovered new concepts is the Néel spin-orbit torque which allows for the antiferromagnetic order parameter to be controlled by an electrical current in common microelectronic circuits. In this review we discuss the utility of antiferromagnets as active and supporting materials for spintronics, the interplay of antiferromagnetic spintronics with other modern research fields in condensed matter physics, and its utility in future "More than Moore" information technologies.

We demonstrate the possibility to drive an antiferromagnetic domain wall at high velocities by fieldlike Néel spin-orbit torques. Such torques arise from current-induced local fields that alternate their orientation on each sublattice of the antiferromagnet and whose orientation depends primarily on the current direction, giving them their fieldlike character. The domain wall velocities that can be achieved by this mechanism are 2 orders of magnitude greater than the ones in ferromagnets. This arises from the efficiency of the staggered spin-orbit fields to couple to the order parameter and from the exchange-enhanced phenomena in antiferromagnetic texture dynamics, which leads to a low domain wall effective mass and the absence of a Walker breakdown limit. In addition, because of its nature, the staggered spin-orbit field can lift the degeneracy between two 180° rotated states in a collinear antiferromagnet, and it provides a force that can move such walls and control the switching of the states.

We demonstrate the possibility to drive an antiferromagnetic domain wall at high velocities by fieldlike Néel spin-orbit torques. Such torques arise from current-induced local fields that alternate their orientation on each sublattice of the antiferromagnet and whose orientation depends primarily on the current direction, giving them their fieldlike character. The domain wall velocities that can be achieved by this mechanism are 2 orders of magnitude greater than the ones in ferromagnets. This arises from the efficiency of the staggered spin-orbit fields to couple to the order parameter and from the exchange-enhanced phenomena in antiferromagnetic texture dynamics, which leads to a low domain wall effective mass and the absence of a Walker breakdown limit. In addition, because of its nature, the staggered spin-orbit field can lift the degeneracy between two 180° rotated states in a collinear antiferromagnet, and it provides a force that can move such walls and control the switching of the states.