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In this paper, the dependence of the spin pumping effect on a layer of tungsten disulfide (WS2) by the inverse Hall spin effect (ISHE) is investigated. The precession motion of the magnetization vector creates the effect of spin pumping on a non-conductive ferrimagnetic film. A stream of polarized spin electrons is then injected into the NM layer of a non-magnetic material such as Pt. This spin current is converted to electric current by the ISHE. We investigated the efficiency of spin injection into tungsten disulfide WS and found that as the film thickness increased, the ISHE voltage also increased and compared this relationship with the theory. Next, we obtained the spin diffusion length and conductivity of the spin mixture by varying the damping coefficient of Gilbert with thickness. As far as we know, similar studies have been performed here on materials such as yttrium-iron-garnet or Mo1-xWxS2 alloy, but not on tungsten disulfide. Studies such as the effect of spin-orbit coupling, the study of second-order Riemann scattering, and the like, have been performed on tungsten disulfide and are still ongoing. We hope this will guide for the development of further studies in this field.

The paper extends study of dipole-exchange spin waves in a circular nanotube composed of an easyplane ferromagnet started by the author in the previous paper. The proposed model considers the magnetic dipole-dipole interaction, the exchange interaction, the anisotropy effects, the damping effects and the general boundary conditions. An equation for the magnetic potential has been obtained for such waves and solved for the case of longitudinal-radial waves. As a result, the dispersion law for the investigated waves has been obtained. After implying boundary conditions, this dispersion law has been complemented with the relation between the wave vector components. This relation has been shown to degenerate into a quasione-dimensional values’ spectrum of the orthogonal wave vector component for a thin nanotube. For the obtained spectral characteristics, graphical representations have been given and numerical evaluations have been performed. The spin wave frequency (calculated according to the obtained dispersion law) for typical values of the nanotube parameters corresponds to typical values observed in experiments, thus substantiating the obtained results. Comparative analysis of the dispersion law obtained in the paper and the analogous law for a nanotube composed of an easy-axis ferromagnet has been performed; differences and similarities have been outlined. It has been shown that branches (that correspond to different orthogonal modes) of the dependencies on the longitudinal wave vector components for both real and imaginary parts of the spin wave frequency are close to parabolic and are essentially apart from each other. The area of application of the obtained results is essentially extended compared to the previous paper. The method that is proposed in the paper can be applied to nanotubes of more complex configurations. [ABSTRACT FROM AUTHOR]

In the paper, dipole--exchange spin waves in a nanotube composed of an easyplane ferromagnet in the presence of a spin-polarized current are studied theoretically. The magnetic dipole--dipole interaction, the exchange interaction, the magnetic anisotropy, the dissipation effects, and influence of the spin-polarized current are considered. For such spin waves, an equation for the magnetic potential is obtained and (for the case of longitudinal-radial waves) solved. As a result, the dispersion law for such waves is found. This dispersion law is complemented with the relation between the wave-vector components, which is shown to degenerate into a quasi-one-dimensional values' spectrum of the orthogonal wave-vector component nearly everywhere. As shown, in most cases, influences of the spin-wave dissipation and spinpolarized current on the real part of its frequency are negligible. Branches (which correspond to different orthogonal modes) of both the real and imaginary parts of the dispersion law are shown to be close to parabolic ones; distance between branches increases with increase of the mode number. Presence of the spin-polarized current can strengthen or weaken the spin-wave damping, creating the 'effective dissipation' and, in some cases, leading to a spin-wave generation. The condition of such a generation is found as well as limitations on the transverse modes' number, for which the generation is possible. As shown, for typical values of nanosystem parameters, only first several modes can be excited via such generation (in most cases, only zero mode or none). The method proposed in the paper can be applied to nanotubes (and other nanosystems) of more complex configurations. [ABSTRACT FROM AUTHOR]

The paper simulates systems in which two types of spin waves can occur, propagating in opposite directions. To achieve this, the quantum slow-wave approximation is employed, allowing for the determination of the probability distribution of occupied states in a quantum two-particle system subjected to perturbations, commonly referred to as Rabi oscillations. This model is specifically applied to a configuration of parallel nanowires exposed to an external electromagnetic wave within the microwave range. The study explores a potential application of the investigated nanostructures in the development of a device for detecting electromagnetic fields. [ABSTRACT FROM AUTHOR]

In this paper, the spin wave theory is applied to the Heisenberg spin bilayer with intralayer ferromagnetic interaction J 1 , intralayer single-ion anisotropy D and interlayer antiferromagnetic interaction J 2 . It is found that the effects of both D and J 2 on the thermodynamic quantities give rise to the two different low-temperature asymptotic behaviors with and without exponential law. For D > 0 , the interlayer antiferromagnetic interaction can induce the appearance of the maximum of the layer magnetization at finite temperatures. At the location of the layer magnetization maximum, the approximate behaviors (such as the power, linear, rational, exponential and logarithmic laws) which are driven by the temperature or the anisotropy, are obtained for the low-temperature thermodynamic properties. It is shown that the presence of antiferromagnetic interlayer interaction J 2 clearly induces more quantum fluctuations than the case where the interlayer interaction J 2 is ferromagnetic. Our results of the layer magnetization agree with the experimental data of the layered van der Waals crystal FeCl2 at low temperatures. In the monolayer case of J 2 = 0 , our results are in agreement with the findings obtained by the existing theories and the quantum Monte Carlo data. [ABSTRACT FROM AUTHOR]

This paper investigates the relationship among interlayer exchange coupling (IEC), Dzyaloshinskii–Moriya interaction (DMI), and multilevel magnetization switching within a Co/Pt/Co heterostructure, where varying Pt thicknesses enable control over the coupling strength. Employing Brillouin Light Scattering to quantify the effective DMI, we explore its potential role in magnetization dynamics and multilevel magnetization switching. Experimental findings show four distinct resistance states under an external magnetic field and spin Hall effect related spin current. We explain this phenomenon based on the asymmetry between Pt/Co and Co/Pt interfaces and the interlayer coupling, which, in turn, influences the DMI and subsequently impacts the magnetization dynamics. Numerical simulations, including macrospin, 1D domain wall, and simple spin wave models, further support the experimental observations of multilevel switching and help uncover the underlying mechanisms. Our proposed explanation, supported by magnetic domain observation using polar-magnetooptical Kerr microscopy, offers insights into both the spatial distribution of magnetization and its dynamics for different IECs, thereby shedding light on its interplay with DMI, which may lead to potential applications in storage devices. [ABSTRACT FROM AUTHOR]

This document is an erratum for a paper titled "Interference patterns of propagating spin wave in spin Hall oscillator arrays" published in the Journal of Applied Physics. The erratum provides the missing caption for Figure 2(b) in the original paper. The misprint in the initial paper does not impact the other results, discussion, or conclusions. The erratum includes various figures and their descriptions related to the study of spin-wave modes in CoFeB/Pt nanowires. [Extracted from the article]

The paper presents the results of research from the analysis of primary magnetization curves for Fe based amorphous alloys. Structural defects in the form of pseudodislocation dipoles occur in amorphous alloys. Using the theory developed by H. Kronmuller called the approach to ferromagnetic saturation, it is possible to indirectly observe internal stresses occurring in the volume of amorphous alloys. The magnetic structure is sensitive to all kinds of inhomogeneities that become visible in the process of high-field magnetization. It has been shown that the cooling rate of the liquid alloy has a great influence on the migration of atoms during the solidification process. Longer time of alloy formation causes more atoms to occupy ordered positions, which results in a change in the distance between the magnetic atoms and a higher degree of structure relaxation. This is indicated by a significant difference in the value of the spin wave stiffness parameter Dspf. The structural differences of the alloys were also investigated using a magnetic balance. It has been shown that the cooling rate influences insignificant differences in the course of thermomagnetic curves and the Curie temperature. [ABSTRACT FROM AUTHOR]

This paper presents the prospects for periodic magnetic nanostructures in the form of magnonic crystals on polymer substrates. Indeed, arrays of magnetic nanostructures on flexible substrates are promising for microwave applications in the GHz frequency range. In particular, the mastery of the potentially coupled physical properties (magnetic and mechanical) allows one to consider devices for microelectronics in general, combining the microwave properties of spin waves with the lightness and conformability of polymer substrates. However, there are still scientific hurdles to be overcome, particularly with regard to the reliability of these systems, which is the focus of this review. Subsequently, we propose a general state of the art, a summary of the precursor works, and a general strategy for the optimization of these systems and their future possibilities. [ABSTRACT FROM AUTHOR]

The correction map method means extended phase-space algorithm with correction map. In our research, we have developed a correction map method, specifically the dissipated correction map method with trapezoidal rule, for numerical simulations of gravitational waves from spinning compact binary systems. This new correction map method, denoted as |$CM3$|⁠ , has shown remarkable performance in various simulation results, such as phase-space distance, dissipated energy error, and gravitational waveform, closely resembling the high-order precision implicit Gaussian algorithm. When compared with the previously used mid-point map which is denoted as |$C_2$|⁠ , the |$CM3$| consistently exhibits a closer alignment with the highly accurate Gaussian algorithm in waveform evolution and orbital trajectory analysis. Through detailed comparisons and analyses, it is evident that |$CM3$| outperforms other algorithms, including |$CM2$| and |$C_2$| mentioned in this paper, in terms of accuracy and precision in simulating spinning compact binary systems. The incorporation of the trapezoidal rule and the optimization with a scale factor |$\gamma$| have significantly enhanced the performance of |$CM3$|⁠ , making it a promising method for future numerical simulations in astrophysics. With the groundbreaking detection of gravitational waves by the LIGO/VIRGO collaboration, interest in this research domain has soared. Our work contributes valuable insights for the application of matched filtering techniques in the analysis of gravitational wave signals, enhancing the precision and reliability of these detection. [ABSTRACT FROM AUTHOR]

Abstract One of the most intriguing properties of magnonic systems is their reconfigurability, where an external magnetic field alters the static magnetic configuration to influence magnetization dynamics. In this paper, we present an alternative approach to tunable magnonic systems. We studied theoretically and numerically a magnonic crystal induced within a uniform magnetic layer by a periodic magnetic field pattern created by the sequence of superconducting strips. We showed that the spin-wave spectrum can be tuned by the inhomogeneous stray field of the superconductor in response to a small uniform external magnetic field. Additionally, we demonstrated that modifying the width of superconducting strips and separation between them leads to the changes in the internal field which are unprecedented in conventional magnonic structures. The paper presents the results of semi-analytical calculations for realistic structures, which are verified by finite-element method computations.

Variable inductors have a simple structure that consists of only magnetic core and primary dc and secondary ac windings, but can control effective inductance of the secondary ac winding by the primary dc current due to magnetic saturation effect. Hence, the variable inductors can be applied as a var compensator in electric power systems. In a previous paper, a lap-winding type three-phase variable inductor, which has the primary dc and secondary ac windings concentrically arranged on the same leg, was presented. It has a good controllability and low distortion current. This paper describes size and weight reduction of the lap-winding type three-phase variable inductor by focusing on the leg width. First, an initial design method of the leg width considering the influence of the dc-biased magnetization is presented. Next, a detailed design of the leg width for the size and weight reduction of the proposed variable inductor is described. Finally, characteristics of the size- and weight-reduced variable inductor were compared to those of the previous variable inductor. It is demonstrated that the core diameter is reduced by about 6% and the weight is decreased by about 50% in comparison with the previous variable inductor. [ABSTRACT FROM AUTHOR]

In this paper, we obtain bounds on the Wilson loop expectations in 4D |$U(1)$| lattice gauge theory, which quantify the effect of topological defects. In the case of a Villain interaction, by extending the non-perturbative technique introduced in [ 24 ], we obtain the following estimate for a large loop |$\gamma $| at low temperatures: |$ |\langle W_\gamma \rangle _{\beta }|\leq \exp \Big (-\frac {C_{GFF}} {2\beta }(1+C \beta e^{- 2\pi ^2 \beta })(|\gamma |+o(|\gamma |)) \Big)\,.$| Our result is in line with recent works [ 4 , 9 , 13 , 15 ] which analyze the case where the gauge group is discrete. In the present case where the gauge group is continuous and Abelian, the fluctuations of the gauge field decouple into a Gaussian part, related to the so-called free electromagnetic wave [ 11 , 23 ], and a gas of topological defects. As such, our work gives new quantitative bounds on the fluctuations of the latter which complement the works by Guth and Frölich-Spencer [ 17 , 27 ]. Finally, we improve, also in a non-perturbative way, the correction term from |$e^{-2\pi ^2\beta }$| to |$e^{-\pi ^2\beta }$| in the case of the free-energy of the system. This provides a matching lower-bound with the prediction of Guth [ 27 ] based on renormalization group techniques. [ABSTRACT FROM AUTHOR]

In this paper, we study the influence of the vortices on the fluctuations of 2d$2d$ systems such as the Coulomb gas, the Villain model, or the integer‐valued Gaussian free field (GFF). In the case of the 2d$2d$ Villain model, we prove that the fluctuations induced by the vortices are at least of the same order of magnitude as the ones produced by the spin wave. We obtain the following quantitative upper bound on the two‐point correlation in Z2$\mathbb {Z}^2$ when β>1$\beta >1$⟨σxσy⟩βVillain⩽C1∥x−y∥212πβ1+βe−(2π)22β.$$\begin{align*} \hspace*{20pt}\langle \sigma _x \sigma _y\rangle _{\beta }^{\rm Villain}\leqslant C \, {\left(\frac{1}{\Vert x-y\Vert _2}\right)}^{\frac{1}{2\pi \beta }{\left(1+\beta e^{-\frac{(2\pi)^2}{2} \beta }\right)}}. \end{align*}$$The proof is entirely nonperturbative. Furthermore, it provides a new and algorithmically efficient way of sampling the 2d$2d$ Coulomb gas. For the 2d$2d$ Coulomb gas, we obtain the following lower bound on its fluctuations at high inverse temperature: EβCoul⟨Δ−1q,g⟩⩾exp(−π2β+o(β))⟨g,(−Δ)−1g⟩.$$\begin{align*} \hspace*{10pt}{ \mathbb {E}_{\beta }^{\,Coul} \bigl [ \langle \Delta ^{-1}q, g\rangle \bigr ]} \geqslant \exp (-\pi ^2 \beta + o(\beta)) \langle g,(-\Delta)^{-1}g\rangle. \end{align*}$$This estimate coincides with the predictions based on Renormalization group (RG) analysis by José et al. [Phys. Rev. B 16 (1977), no. 3, 1217] and suggests that the Coulomb potential Δ−1q$\Delta ^{-1}q$ at inverse temperature β$\beta$ should scale like a GFF of inverse temperature of order exp(π2β)$\exp (\pi ^2 \beta)$. Finally, we transfer the above vortex fluctuations via a duality identity to the integer‐valued GFF by showing that its maximum deviates in a quantitative way from the maximum of a usual GFF. More precisely, we show that with high probability when β>1$\beta >1$maxx∈[−n,n]2Ψn(x)⩽2βπ1−βe−(2π)2β2logn,$$\begin{equation*} \hspace*{20pt}\max _{x\in [-n,n]^2} \Psi _n(x) \leqslant \sqrt {\frac{2\beta }{\pi } {\left(1 - \beta e^{- \frac{(2\pi)^2\beta }{2} } \right)}} \log n \,, \end{equation*}$$where Ψn$\Psi _n$ is an integer‐valued GFF in the box [−n,n]2$[-n,n]^2$ at inverse temperature β−1$\beta ^{-1}$. Applications to the free energies of the Coulomb gas, the Villain model, and the integer‐valued GFF are also considered. [ABSTRACT FROM AUTHOR]

A spin-wave delay-line active-ring oscillator has recently been proposed as a suitable substrate to implement the physical reservoir computing model. The concept displays the required properties of fading memory and nonlinearity characteristic to the model. In this paper, we improve the concept by increasing the signal delay time in the yttrium-iron garnet film by more than four times, and we examine further the improved system by evaluating experimentally the performance on two benchmark classification tasks. The short-term memory (STM) task evaluates the linear memory characteristics of the RC, while the parity-check (PC) task evaluates the nonlinear computing capability. Adequate performance on both is achieved, and the linear memory is shown to be strongly dependent on the synchronization between the reservoir computer (RC) inputs and the active-ring circulation time. The extended delay time and other major improvements result in STM and PC capacities reaching maximum values of 4.68 and 1.74, respectively. [ABSTRACT FROM AUTHOR]

This paper provides a tutorial overview over recent vigorous efforts to develop computing systems based on spin waves instead of charges and voltages. Spin-wave computing can be considered a subfield of spintronics, which uses magnetic excitations for computation and memory applications. The Tutorial combines backgrounds in spin-wave and device physics as well as circuit engineering to create synergies between the physics and electrical engineering communities to advance the field toward practical spin-wave circuits. After an introduction to magnetic interactions and spin-wave physics, the basic aspects of spin-wave computing and individual spin-wave devices are reviewed. The focus is on spin-wave majority gates as they are the most prominently pursued device concept. Subsequently, we discuss the current status and the challenges to combine spin-wave gates and obtain circuits and ultimately computing systems, considering essential aspects such as gate interconnection, logic level restoration, input–output consistency, and fan-out achievement. We argue that spin-wave circuits need to be embedded in conventional complementary metal–oxide–semiconductor (CMOS) circuits to obtain complete functional hybrid computing systems. The state of the art of benchmarking such hybrid spin-wave–CMOS systems is reviewed, and the current challenges to realize such systems are discussed. The benchmark indicates that hybrid spin-wave–CMOS systems promise ultralow-power operation and may ultimately outperform conventional CMOS circuits in terms of the power-delay-area product. Current challenges to achieve this goal include low-power signal restoration in spin-wave circuits as well as efficient spin-wave transducers. [ABSTRACT FROM AUTHOR]

Spin waves (SWs) are promising objects for signal processing and future quantum technologies due to their high microwave frequencies with corresponding nanoscale wavelengths. However, the nano‐wavelength SWs generated so far are limited to low frequencies. In the paper, using micromagnetic simulations, it is shown that a microwave‐pumped SW mode confined to the cavity of a thin film magnonic crystal (MC) can be used to generate waves at tens of GHz and wavelengths well below 50 nm. These multi‐frequency harmonics of the fundamental cavity mode are generated when the amplitude of the pumping microwave field exceeds a threshold, and their intensities then scale linearly with the field intensity. The frequency of the cavity mode is equal to the ferromagnetic resonance frequency of the planar ferromagnetic film, which overlaps with the magnonic bandgap, providing an efficient mechanism for confinement and magnetic field tunability. The effect reaches saturation when the microstrip feed line covers the entire cavity, making the system feasible for realization. [ABSTRACT FROM AUTHOR]

In this paper, a magnon-bandgap controllable artificial domain wall waveguide is proposed by means of micromagnetic simulation. By the investigation of the propagation behavior and dispersion relationship of spin waves in artificial domain wall waveguides, it is found that the nonreciprocal propagation of spin waves in the artificial domain walls is mainly affected by the local effective exchange field, and the magnon bandgap can be controlled by changing the maximum value of the effective exchange field. In addition, it is observed that the artificial domain wall waveguides are structurally more stable than the natural domain wall waveguides under the same spin wave injection conditions, and the magnon bandgap of the artificial domain wall waveguides can be adjusted by its width and magnetic anisotropy parameters. The bandgap controllable artificial domain wall scheme is beneficial to the miniaturization and integration of magnon devices and can be applied to future magnonic technology as a high-pass filter with adjustable cutoff frequency. [ABSTRACT FROM AUTHOR]

Spin waves are a promising prospect for the development of microwave information processing devices. A major obstacle in the study of spin waves is the large intrinsic spin-wave damping in most known magnetic materials. Viable spin-wave amplification techniques are thus required to make further progress in the development of spin-wave-based logic devices. In this paper, we investigate a novel technique of parametric modulation of spin waves using bulk acoustic waves. Although it is not a conclusive proof of parametric amplification, we show that bulk acoustic waves at twice the frequency of the propagating spin waves on coupling into an yttrium iron garnet film can modulate the amplitude of the spin wave. This paper provides insight into magnon-phonon interactions, and suggests a new mechanism to compensate for inherent losses in spin-wave propagation in spin-wave-based logic devices. [ABSTRACT FROM AUTHOR]

Applications of magnetic memory devices greatly benefit from ultra-fast, low-power switching. In this paper, we propose a method for how this can be achieved efficiently in a nano-sized synthetic antiferromagnet by using perpendicular-to-the-plane picosecond-range magnetic-field pulses. Our detailed micromagnetic simulations, supported by analytical results, yield the parameter space where inertial switching and relaxation-free switching can be achieved in the system. We furthermore discuss the advantages of dynamic switching in synthetic antiferromagnets and, specifically, their relatively low-power switching as compared with that in single ferromagnetic particles. Finally, we show how the excitation of spin waves in the system can be used to significantly reduce the post-switching spin oscillations for practical device geometries. [ABSTRACT FROM AUTHOR]

This paper presents a system-level efficiency analysis, a rapid design methodology, and a numerical demonstration of efficient sub-micron, spin-wave transducers in a microwave system. Applications such as Boolean spintronics, analog spin-wave-computing, and magnetic microwave circuits are expected to benefit from this analysis and design approach. These applications have the potential to provide a low-power, magnetic paradigm alternative to modern electronic systems, but they have been stymied by a limited understanding of the microwave, system-level design for spin-wave circuits. This paper proposes an end-to-end microwave/spin-wave system model that permits the use of classical microwave network analysis and matching theory towards analyzing and designing efficient transduction systems. This paper further compares magnetostatic-wave transducer theory to electromagnetic simulations and finds close agreement, indicating that the theory, despite simplifying assumptions, is useful for rapid yet accurate transducer design. It further suggests that the theory, when modified to include the exchange interaction, will also be useful to rapidly and accurately design transducers launching magnons at exchange wavelengths. Comparisons are made between microstrip and co-planar waveguide lines, which are expedient, narrowband, and low-efficiency transducers, and grating and meander lines that are capable of high-efficiency and wideband performance. The paper concludes that efficient microwave-to-spin-wave transducers are possible and presents a meander transducer design on YIG capable of launching λ = 500 nm spin waves with an efficiency of − 4.45 dB and a 3 dB-bandwidth of 134 MHz. [ABSTRACT FROM AUTHOR]

In this paper, we demonstrate that physical waves can be used to perform convolutions as part of a state-of-the-art neural network architecture. In particular, we show that the damping of waves, which is unavoidable in a physical implementation, does not diminish their usefulness in performing the convolution operations required in a convolutional neural network (CNN), and the damping only slightly decreases the classification accuracy of the network. These results open the door for wave-based hardware accelerators for CNNs. [ABSTRACT FROM AUTHOR]

This paper presents new experimental data that enable the observed processes in nonlinear ferrite lines to be related with the theoretical positions of the spin waves of the magnetization precession under the conditions of a high-power microwave. Such an approach has not been considered in earlier discussions on the subject and can contribute to the theory of the generation of oscillations in a gyromagnetic ferrite medium. These new aspects were used to design a new type of generator. The specific feature is the presence of regularity in the ferrite lines in the generation mode of microwave oscillations. The repeating regularity enabled the implementation of multistage pulse shape converters capable of operating in two modes and providing extreme parameters of the output pulses. Two variants of multistage converters of nanosecond high-voltage pulse shapes with a duration of ∼4 ns at a half-height and with an amplitude of −500 kV were designed and tested. The assembly of the converters and the driving generator are described in the stationary setup. In the first case, the rise time shortened to ∼45 ps, and the amplitude increased to −850 kV due to the sharpening of a pulse and the formation of a shock wave by the cascade of three nonlinear transmission lines. A record rate for the increase of the leading peak voltage of ∼15.5 MV/ns was reached. In the second case, the new approach for the generation of a sequence of subnanosecond pulses was presented and tested, and each pulse of the previous stage was modulated by the next stage doubling the number of pulses while conserving a deeper modulation. As a result, at the top of the incident pulse, a sequence of subnanosecond peaks with a large modulation depth (∼70%) was formed when the maximum voltage amplitude reached −700 kV. The results of the emission of such pulses are also presented. [ABSTRACT FROM AUTHOR]

Rotating waves can be observed in structures with periodic conditions, such as cylinders and spheres. Compared with traveling waves and standing waves, rotating waves have received less attention. In this paper, an odd elastic dynamic model of the cylindrical shells is established, and the dispersion relation, traveling waves, and standing waves are investigated. The non-Hermitian rotating waves and single-handedness chiral standing spin waves are reported, which are novel dynamic phenomenon caused by odd elastic effects. Waves generally cannot propagate in passive materials with vanishingly small elastic modulus. However, a unidirectional wave with the highest cut off frequency can occur in an odd elastic cylindrical shell with vanishingly small elastic modulus. For incompletely restrained end displacements, the odd elastic cylindrical shell can also generate a hybrid mode combining standing spin waves with unidirectional waves. [ABSTRACT FROM AUTHOR]

Magnetic heterostructures consisting of single-crystal yttrium iron garnet (YIG) films coated with platinum are widely used in spin-wave experiments related to spintronic phenomena such as the spin-transfer-torque, spin-Hall, and spin-Seebeck effects. However, spin waves in YIG/Pt bilayers experience much stronger attenuation than in bare YIG films. For micrometer-thick YIG films, this effect is caused by microwave eddy currents in the Pt layer. This paper reports that by employing an excitation configuration in which the YIG film faces the metal plate of the microstrip antenna structure, the eddy currents in Pt are shunted and the transmission of the Damon-Eschbach surface spin wave is greatly improved. The reduction in spin-wave attenuation persists even when the Pt coating is separated from the ground plate by a thin dielectric layer. This makes the proposed excitation configuration suitable for injection of an electric current into the Pt layer and thus for application in spintronics devices. The theoretical analysis carried out within the framework of the electrodynamic approach reveals how the platinum nanolayer and the nearby highly conductive metal plate affect the group velocity and the lifetime of the Damon-Eshbach surface wave and how these two wavelength-dependent quantities determine the transmission characteristics of the spin-wave device. [ABSTRACT FROM AUTHOR]

In this paper, spin-to-charge current conversion properties in the Weyl semimetal TaP by means of the inverse Rashba-Edelstein effect (IREE) with the interfacial integration of this quantum material with the ferromagnetic metal Permalloy (Py = Ni81Fe19) are presented. The spin currents are generated in the Py layer by the spin pumping effect (SPE) from microwave-driven ferromagnetic resonance and are detected by a dc voltage along the TaP crystal, at room temperature. A field-symmetric voltage signal is observed without the contamination of asymmetrical lines due to spin rectification effects observed in studies using metallic ferromagnets. The observed voltage is attributed to spin-to-charge current conversion based on the IREE, made possible by the spin-orbit coupling induced intrinsically by the bulk band structure of Weyl semimetals. The measured IREE coefficient λIREE = (0.30 ± 0.01) nm is two orders of magnitude larger than in graphene and is comparable to or larger than the values reported for some metallic interfaces and for several topological insulators. [ABSTRACT FROM AUTHOR]

Active control of propagating short-wavelength spin waves in perpendicularly magnetized materials is promising for designing nanoscale magnonic devices. One method of manipulating spin waves on the nanoscale is through their interaction with magnetic textures, an example of which is the magnetic skyrmion—a particle-like topological object stabilized in thin film heterostructures by the Dzyaloshinskii–Moriya interaction (DMI) and perpendicular magnetic anisotropy. In this paper, the interaction between spin waves and skyrmions is studied using micromagnetic simulations. The magnetic parameters chosen are similar to those found experimentally, leading to a skyrmion with an extended core of reversed magnetization. The effect of a propagating spin wave on the skyrmion is to cause the emission of a secondary spin wave by the skyrmion. At low frequencies, where the incoming spin wave wavelength is much larger than the skyrmion, this leads to a nearly circular re-emitted spin wave. The pattern of emission becomes increasingly complex at higher frequencies as the wavelength becomes similar to the skyrmion size due to the complex excitation of the extended core. The emitted spin wave profile can be controlled by altering the size of the skyrmion through the magnitude of the DMI, providing a method of tuning the system. [ABSTRACT FROM AUTHOR]

This paper presents the results of measuring the main parameters of the ferromagnetic and spin-wave resonance spectra (resonant field, linewidth, and intensity) of single-layer permalloy films at various angles in the out-of-plane orientation. The effect of the type of surface conditions on the angular dependence of the intensity ratio of adjacent modes is studied. A correspondence is established between the angle of the applied constant magnetic field with respect to the normal to the film and the change in the oscillation type from uniform to nonuniform. The revealed features of the angular dependences of the resonant field and the intensity of the spectral peak can be successfully used in the identification of microwave spectra. The fundamental magnetic parameters (effective magnetization, exchange interaction constant, surface anisotropy constant, and perpendicular anisotropy field) were determined. [ABSTRACT FROM AUTHOR]

With the development of new nanofabrication technologies and measurement techniques, the interest of researchers is moving toward 3D structures and 3D magnetization textures. Special attention is paid to the topological magnetization textures, particularly hopfions. In this paper, we investigate the magnetization dynamics of the hopfion through the numerical solution of the eigenvalue problem. We show that the spectrum of spin-wave modes of the hopfion is much richer than those attainable in ferromagnetic resonance experiments or time-domain simulations reported so far. We identified four groups of modes that differ in the character of oscillations (clockwise or counter-clockwise rotation sense), the position of an average amplitude localization along the radial direction, and different oscillations in the vertical cross section. The knowledge of the full spin-wave spectrum shall help in hopfion identification, understanding of the interaction between spin waves and hopfion dynamics as well as the development of the potential of hopfion in spintronic and magnonic applications. [ABSTRACT FROM AUTHOR]

In this paper the micromagnetic simulation of thermal generation of spin waves in permalloy is shown. The simulation was carried out with MuMax3 software. The relationship between the value of external applied field and frequency of the generated spin waves, as well as the influence of sample temperature on spin waves amplitude were investigated and they are described. Thermal generation of spin waves was simulated for room temperatures. [ABSTRACT FROM AUTHOR]

In this paper, we introduce a design concept for a spin-torque nano-oscillator capable of generating spin-wave (SW) packets using magnetic droplets tuned by an electric field (E-field). A comparison is made between this device concept and a conventional setup, where SWs are generated by an oscillating external magnetic field, revealing similar results. The design incorporates a CoFeB layer with perpendicular magnetic anisotropy, acting as a waveguide for propagating SW packets. Adjusting the pulse width of applied E-fields leads to observable changes in the amplitude and periodicity of SW packets. Additionally, this study explores the potential of encoding SW packets as binary signals ("0" and "1"). The findings offer valuable insights into the applications of magnetic droplets and electric-field tuning for spin-wave packet generation, with potential implications for various spintronic devices and technologies. [ABSTRACT FROM AUTHOR]

In this paper, we construct equations that help us calculate the energy of vector fields representing some flows described with the help of nonlinear optical systems in S 2 spherical space. For this, we make use of energy equations of a vector fields on a surface, which we obtain by describing the flow motion as the time-dependent change of position. Geometrically, the wave propagation in an electromagnetic media can represent the help of a curve representing the trajectory of the magnetic field. Considering an antiferromagnetic flux in this manner, the Heisenberg antiferromagnet (anti-f-magnetic) spin wave equation provides soliton solutions for the electrodynamic systems, spin wave theory and optical systems. In this study, we obtain the energy equations of a magnetic flux with Heisenberg anti-ferromagnet spin wave chain, taking into account the viscosity effect. Here, we also present an example of energy calculations in recursive systems with the help of the energy equation of a chosen recursive vector field representing the magnetic flux. [ABSTRACT FROM AUTHOR]

Proximity effect, which is the coupling between distinct order parameters across interfaces of heterostructures, has attracted immense interest owing to the customizable multifunctionalities of diverse 3D materials. This facilitates various physical phenomena, such as spin order, charge transfer, spin torque, spin density wave, spin current, skyrmions, and Majorana fermions. These exotic physics play important roles for future spintronic applications. Nevertheless, several fundamental challenges remain for effective applications: unavoidable disorder and lattice mismatch limits in the growth process, short characteristic length of proximity, magnetic fluctuation in ultrathin films, and relatively weak spin–orbit coupling (SOC). Meanwhile, the extensive library of atomically thin, 2D van der Waals (vdW) layered materials, with unique characteristics such as strong SOC, magnetic anisotropy, and ultraclean surfaces, offers many opportunities to tailor versatile and more effective functionalities through proximity effects. Here, this paper focuses on magnetic proximity, i.e., proximitized magnetism and reviews the engineering of magnetism‐related functionalities in 2D vdW layered heterostructures for next‐generation electronic and spintronic devices. The essential factors of magnetism and interfacial engineering induced by magnetic layers are studied. The current limitations and future challenges associated with magnetic proximity‐related physics phenomena in 2D heterostructures are further discussed. [ABSTRACT FROM AUTHOR]

In this paper, we propose a one band tight binding model Hamiltonian for the newly discovered 122-type Selenide family of the iron-based system incorporated with the nearest-neighbor (NN) and the next-nearest-neighbor (NNN) hopping integrals t 1 and t 2 , respectively. The spin–spin interactions of the electrons leading to the antiferromagnetic spin density wave (SDW) order have been studied at wave vector Q = (π , π ∕ 2). The electron Green's functions are calculated from the Hamiltonian model using Green's function technique and finally the SDW gap equation is derived and studied using their NN and NNN spin coupling g 1 and g 2 , respectively. [ABSTRACT FROM AUTHOR]

This paper presents a model for the computation of two-port parameters from the configuration of a typical Magnonic device involving two coplanar waveguides. A Permalloy thin film is saturated using an appropriate dc field. The first waveguide then performs the function of excitation of spin waves by superposition of an RF field. The second waveguide detects the excited wave vector in Damon–Eshbach mode at resonance frequency. The model is solved using the generalized mean residual method for a linearized approximation of the Landau–Lifshitz–Gilbert equation coupled with Maxwell equations. Complex impedance matrices from the two-port network are extracted for both uniformly saturated and non-uniform initial ground states. Findings report low absorption potential and shift in resonance frequency for highly non-uniform ground states. Validation of the model for uniformly saturated ground states is performed against experimental and semi-analytical findings, showing good agreement. [ABSTRACT FROM PUBLISHER]

Spin projected wave functions are generalizations of the Hartree–Fock wave function. Among them, the Half‐Projected Hartree–Fock (HPHF) wave function is a nearly pure wave function of spin and recovers a small part of the spin correlation energy. This paper reviews the history of the HPHF theory, not only from the conceptual point of view but also providing a compilation of the publications of this method over the years until now. In addition, the extension of the HPHF method to the calculation of excited states with the same symmetry as the ground state will be discussed. The possible variational collapse during the calculation of a singlet excited state of the same symmetry as the ground state is avoided by orthogonalizing a pair of corresponding orbitals, one occupied and one virtual orbital, at every step of the variational process. As an example, the potential energy surfaces of the S0 ground and 1S1(n, π*) first excited state of the formic acid HCOOH are calculated. [ABSTRACT FROM AUTHOR]

In this paper, we theoretically investigate the stability of spin-wave solitons in Bose-Einstein condensates of repulsive magnons, confined by an inhomogeneous external magnetic field described by a Gaussian well. For this purpose, we use the quasi-one-dimensional Gross-Pitaevskii equation to describe the behavior of the condensate. In order to solve the Gross-Pitaevskii equation, we used two different approaches: one analytical (variational method) and another numerical (split-step Crank-Nicolson method). The stability of the solutions and the validation of the numerical results were confirmed, respectively, through the anti-VK criterion and the virial theorem. Furthermore, the simulations described the behavior of physical quantities of interest such as chemical potential, energy per magnon and central density as a function of the nonlinearity of the model (magnon-magnon interactions). The theoretical results provide subsidies for a better understanding of the nonlinear phenomena related to the Bose-Einstein condensates of magnons in ferromagnetic films. [ABSTRACT FROM AUTHOR]

Summary: The universe is filled with electromagnetic fields, quantum fields, and the other different field. They penetrate and interact with each other. Just as the interaction between magnetic materials are due to the magnetic field around the magnet contacting another magnet, between the quanta can also interact with each other through magnetic fields. Through the study of quantum mechanics and related theories of brain science, the article puts forward the following viewpoints: between quantum, which has entanglement state, cannot only interact through magnetic fields but also generate quantum induction fields to generate quantum induction waves. The entangled quantum generated spin waves are connected to each other based on quantum inductive waves to form a quantum inductive network. Then, the information is transmitted through resonance to realize the communication between all things. Thus, all things in the universe can be interconnected based on quantum entanglement effects. By analyzing the construction mode of the internet network, the paper proposes the architecture of the quantum induction communication system and the basic topology of a quantum induction internet network. Several thought experiment schemes were designed, and the information transmission between the ordinary objects and between the people and ordinary objects is studied as an example. The analysis points out the main problems faced by the construction of the quantum induction internet. It points out that the significance of constructing of the network of All things interconnect based on quantum entanglement effect is that all living bodies and nonliving bodies in the heaven and earth can be connected and communicate with each other. [ABSTRACT FROM AUTHOR]

We dedicate this paper to the memory of Victor Pavlovich Silin. The paper contains a modern formulation of the principles and main results of the quantum theory of spin waves in a conduction electron system in a crystal that does not have spontaneous spin ordering. Based on the quantum Fermi-liquid kinetic equation, we describe the propagation of electron spin oscillations in an isotropic system along the direction of a quantizing magnetic field while analyzing the dispersion equation, including the classical and quantum contributions. We present the fundamental results on quantum physics of Silin's spin waves consisting in the existence of quantum magnetic field oscillations of wave frequencies in the region, where the classical collisionless absorption is absent and new quantum spin waves appear in the transparency windows formed due to quantum suppression of classical absorption. [ABSTRACT FROM AUTHOR]

In this paper, based on the basic principles of thermodynamics, we explore the hydrodynamic regime of interacting Lifshitz field theories in the presence of broken rotational invariance. We compute the entropy current and discover new dissipative effects which are consistent with the principle of local entropy production in the fluid. In our analysis, we consider both the parity even and the parity odd sector upto first order in the derivative expansion. Finally, we argue that the present construction of the paper could be systematically identified as that of the hydrodynamic description associated with spin waves (away from the domain of quantum criticality) under certain limiting conditions. [ABSTRACT FROM AUTHOR]

In this paper, we present the most recent results on the development of magnonic holographic memory (MHM). MHM is a type of holographic device, which uses spin waves for data transfer and processing. The most appealing properties of MHM include parallel read-out and database search. We present experimental data showing parallel read-out of four magnetic memory states. In this experiment, the internal magnetic state is recognized by the level of the output inductive voltage produced by the spin-wave interference. We also present the experimental data showing database search in the MHM. In this experiment, the search for the maximum output is accomplished by utilizing spin-wave superposition. The experiments were carried out for six- and eight-terminal yttrium iron garnet-based prototypes. Potentially, magnonic holographic devices can be implemented as complementary memory/logic units to digital processors. Physical limitations and technological constraints of the spin-wave approach are also discussed. [ABSTRACT FROM PUBLISHER]

Chirality of antiferromagnetic spin waves as an intrinsic degree of freedom has been attracting considerable attention due to its potential applications for magnonic devices. In this paper, atomistic-scale dynamics simulations were conducted to investigate the chirality of spin wave resonant modes in ferrimagnetic alloy GdxFe1−x (0 < x <1) under different proportion x and external magnetic fields near the angular momentum compensation point. Simulation results reveal that as the proportion of Gd increases, the resonance mode of spin waves undergoes two distinct handedness flipping at magnetization compensation point and angular momentum compensation point. When the proportion x deviates from the magnetization compensation point, a frequency degeneracy point emerges at a non-zero magnetic field, indicating that the chirality of spin waves can also be switched by an external magnetic field. A theoretical analysis is developed to explain the observed phenomena. These findings provide valuable insights into the control and manipulation of spin wave chirality in ferrimagnetic alloys, with potential implications for the development of spin-based devices and technologies. [ABSTRACT FROM AUTHOR]

The multistep synthesis of a hybrid material based on a TiO2 core with an immobilized triazine-based copper(II)-NNN pincer complex is reported. The formation of the material was confirmed by FT-IR spectroscopy and elemental and thermogravimetric analyses, and the loading by copper ions was quantified by ICP/OES analysis. The properties of the hybrid material were further investigated by X-ray photoelectron spectroscopy (XPS), contiuous wave electron spin resonance (CW-ESR), UV-vis spectroscopy, and argon sorption. Efficient and regioselective synthesis of 1,4-disubstituted 1,2,3-triazoles was achieved by employing the hybrid material as a catalyst in a mixture of H2O/EtOH as a green solvent with excellent catalytic activity with a TOF up to 495 h−1 at 50 °C. The reusability of the prepared hybrid material in the catalytic reaction was possible over five consecutive runs without significant loss of catalytic activity. The described method represents an effective way to ensure sustainable use of pincer complexes in catalytic systems by immobilizing them on solid supports, resulting in a hybrid organic–inorganic catalyst platform. [ABSTRACT FROM AUTHOR]

Determining the prime factors of a given number N is a problem that requires super-polynomial time for conventional digital computers. A polynomial-time algorithm was invented by Shor for quantum computers. In this paper, we present experimental data that demonstrate prime factorization using spin-wave interference but without quantum entanglement. Prime factorization includes three major steps. First, a general-type computer calculates the sequence of numbers mk mod(N), where N is the number to be factorized, m is a randomly chosen positive integer, and k = 1, 2, 3, 4, 5, 6… . Next, the period of the calculated sequence r is determined by exploiting spin-wave interference. Finally, the general-type computer determines the primes based on the obtained r. The experiment for period finding was conducted on a six-terminal Y3Fe2 (FeO4) 3 device. We chose number 15 for testing and determined its primes using a sequence of measurements. The obtained experimental data for a micrometer-sized prototype aimed to demonstrate the benefits of using spin-wave devices to solve complex computational problems. Scalability is one of the major strengths inherent in this type of wave-based device, which may provide a route to nanometer-sized logic circuits. We discuss the physical and technological limitations of this approach, which define the maximum size of N and the computational speed. Although this classical approach cannot compete with the quantum algorithm in terms of efficiency, magnonic holographic devices can potentially be used as complementary logic units aimed at speeding up prime factorization for classical computers. [ABSTRACT FROM AUTHOR]