Abstract Miniaturization of magnonic devices for wave-like computing requires emission short-wavelength spin waves, a key feature that cannot be achieved with microwave antennas. In this paper, we propose tunable source waves based on highly localized and strongly pinned magnetic domain walls in ferroelectric-ferromagnetic bilayers. When driven into oscillation by spin-polarized current, the emit same frequency as excitation current. The amplitude emitted range attainable frequencies depend...

We present a first-principles study of the electronic, magnetic, and transport properties topological insulator ${\mathrm{Bi}}_{2}{\mathrm{Te}}_{3}$ doped with Mn atoms in substitutional $({\mathrm{Mn}}_{\mathrm{Bi}})$ interstitial van der Waals gap positions $({\mathrm{Mn}}_{i})$, which act as acceptors donors, respectively. The effect native ${\mathrm{Bi}}_{\mathrm{Te}}$- ${\mathrm{Te}}_{\mathrm{Bi}}$-antisite defects their influence on calculated electronic is also investigated. have...

Femtosecond laser pulses can induce ultrafast demagnetization as well generate bursts of hot-electron spin currents. In trilayer valves consisting two metallic ferromagnetic layers separated by a nonmagnetic one, currents excited an ultrashort pulse propagate from the first layer through spacer, reaching second magnetic layer. When magnetizations are noncollinear, this current exerts torque on moments in ferromagnet. Since is acting only within subpicosecond timescale, it excites coherent...

Manipulation of magnetic domain walls via a helicity-independent laser pulse has recently been experimentally demonstrated and various physical mechanisms leading to wall dynamics have discussed. Spin-dependent superdiffusive transport hot electrons identified as one the possible ways affect wall. Here, we develop model based on spin-dependent study laser-induced through smooth We show that spin transfer between neighboring domains can enhance ultrafast demagnetization in More importantly,...

Electronic, magnetic, and transport properties of the antiferromagnetic (AFM) CuMnAs alloy with tetragonal structure, promising for AFM spintronics, are studied from first principles using Vienna ab-initio simulation package. We investigate site-occupation sublattices lattice parameters three competing phases. analyze factors that determine which conceivable structures will prevail. then estimate formation energies possible defects experimentally prepared structure. Mn$_{\rm Cu}$- Cu$_{\rm...

Ultrafast demagnetization induced by femtosecond laser pulses in thin metallic layers is caused the outflow of spin-polarized hot electron currents describable superdiffusive transport model. These laser-generated spin can cross interface into another magnetic layer and give rise to magnetization dynamics valves with noncollinear magnetizations. To describe ultrafast such nanostructures we develop here theory for general multilayers. Specifically, introduce an Al/Ni/Ru/Fe/Ru multilayer...

Spin-transfer torque and current-induced spin dynamics in spin-valve nanopillars with the free magnetic layer located between two films of fixed moments is considered theoretically. The spin-transfer limit diffusive transport calculated as a function configuration. It shown that noncollinear configuration outermost layers has strong influence on central layer. Employing macrospin simulations we make some predictions valves composed various layers. We also present formula for critical current...

Melting of a particle lattice in two dimensional systems substantially differs from the one three dimensions. The most prominent theory melting 2D, formulated by Kosterlitz, Thouless, Halperin, Nelson, and Young (KTHNY), describes solid-liquid phase transition as two-step process, where solid turns into liquid via hexatic phase. microscopic nature this process lies excitation unbinding topological defects 2D lattice. KTHNY scenario has been observed number physical systems. Here, we...

Stability conditions for a spin valve with composite free layer consisting of two antiferromagnetically coupled films---known as synthetic antiferromagnet or ferrimagnet---is studied theoretically by means the linearized Landau-Lifshitz-Gilbert equations. The Lyapunov and Routh-Hurwitz methods have been used to examine stability subject external in-plane magnetic field electric current flowing perpendicularly layers' plane. A simple formula critical density, valid variety structures, also...

Magnetization switching due to a current-pulse in symmetric and asymmetric spin valves is studied theoretically within the macrospin model. The process corresponding parameters are shown depend significantly on pulse duration also interplay of torques transfer external magnetic field. This leads peculiar features phase diagram. These standard valves, where torque stabilizes one configurations (either parallel or antiparallel) destabilizes opposite one, differ from those nonstandard...

Ultrafast demagnetization of magnetic layers pumped by a femtosecond laser pulse is accompanied nonthermal spin-polarized current hot electrons. These spin currents are studied here theoretically in valve with noncollinear magnetizations. To this end, we introduce an extended model superdiffusive transport that enables the treatment configurations, and apply it to perpendicular geometry. We show how spin-transfer torques arise due mechanism calculate their action on magnetization present, as...

Doping ${\mathrm{Bi}}_{2}{\mathrm{Se}}_{3}$ by magnetic ions represents an interesting problem since it may break the time-reversal symmetry needed to maintain topological insulator character. Mn dopants in represent one of most studied examples here. However, there is a lot open questions regarding their ordering. In experimental literature different Curie temperatures or no ferromagnetic order at all are reported for comparable concentrations. This suggests that ordering phenomena complex...

We utilize neural network quantum states (NQS) to investigate the ground state properties of Heisenberg model on a Shastry-Sutherland lattice using variational Monte Carlo method. show that already relatively simple NQSs can be used approximate this in its different phases and regimes. first compare several types with each other small lattices benchmark their energies against exact diagonalization results. argue when precision, generality, computational costs are taken into account, good...

Current-induced dynamics in spin valves including a composite free layer with antiferromagnetic interlayer exchange coupling is studied theoretically within the diffusive transport regime. We show that current-induced of synthetic antiferromagnet significantly different from ferrimagnet. From macrospin simulations we obtain conditions for switching layer, as well appearance various self-sustained dynamical modes. Numerical are compared simple analytical models critical current based on...

Current-induced spin transfer torque in relatively thick N\'eel domain walls ferromagnetic metals/semiconductors is considered theoretically the linear response regime. Using quasiclassical approximation and unitary transformation we calculate nonequilibrium (current-induced) accumulation wall. The current-induced density then used to determine adiabatic nonadiabatic components of torque. results show that as well its nonadiabaticity can be enhanced by spin-conserving momentum scattering...

Spin-wave spectra of a double magnetic layer are calculated theoretically in the macroscopic limit. Magnetic dynamics is described terms Landau-Lifshitz-Gilbert equation, and both static (of Ruderman-Kittel-Kasuya-Yosida type) dynamic (via spin pumping) interlayer couplings taken into account. The influence pumping transfer torque on spin-wave (frequency damping factor) has been studied for parallel antiparallel configurations. spectrum state reciprocal, while configuration it nonreciprocal....

A semiclassical description of diffusive spin transport in valves, which takes into account the transverse components accumulation, is used to calculate second harmonic voltage response a low-frequency current. The applied single as well dual with magnetic moment sensing layer slightly tilted out equilibrium position by an in-plane external field. In case double only antiparallel configuration considered since torque this enhanced, while parallel it significantly reduced. both cases...

A theoretical description of spin current injection from a nonmagnetic layer into magnetic one is presented, with the main emphasis on and determination penetration depth component transverse to magnetization. This also determines transfer torque generation. Physically, may be driven by an external electric field or temperature gradient. To determine we used ab initio calculations channel mixing conductances as well transmission. The results are then second harmonic voltage response, which...

We have measured the hot-electron-induced demagnetization of a [Co/Pt]2 multilayer in M(x nm)/Cu(100 nm)/[Co(0.6 nm)/Pt(1.1 nm)]2 samples depending on nature capping layer M and its thickness x. found out that Pt is more efficient than [Co/Pt]X, Cu, or MgO layers converting infrared (IR) photon pulses into hot-electron at given laser power. also maximum relative amplitude achieved for M(x) = (7 nm). Our experimental results show qualitative agreement with numerical simulations based...

We present a theoretical description of spin-transfer torque in spin valve with perpendicularly magnetized polarizer. The polarizer consisting several ultrathin layers is considered as single interfacial magnetic scatterer between two nonmagnetic layers, and included the theory based on diffusive transport via appropriate boundary conditions. model has been used to study systematically current-induced switching both perpendicular in-plane polarizers free layer. wave-function matching ab...