Using numerical and experimental methods, the mechanism of control of the transmission of a spin-wave signal in a three-dimensional magnon splitter, formed by an orthogonal junction of magnetic strips of yttrium iron garnet, has been investigated. It is shown that by variation the size of the air gap between the spin-waveguide sections, it is possible to control the selection of the signal propagating in the output sections of the structure. From an applied point of view, the results obtained can be used to create an interconnection element in multilevel magnon information processing devices for the formation of multilayer magnon network topologies and miniaturization of computing devices based on the principles of magnonics. Key words: spin waves, magnonics, three-dimensional interconnections, micromagnetic modeling. Keywords: spin waves, magnonic, micromagnetic simulations, three-dimensional structure.

Here, we present a study investigating the effects of spin-wave coupling in a structure composed of parallel-oriented magnonic stripes fabricated from thin films of yttrium-iron garnet. The structure consists of two parallel stripes separated by a sufficiently small gap to enable dipolar coupling, while a third stripe is positioned atop the lateral system, forming an asymmetric three-dimensional (3D) coupler geometry. Through the utilization of Brillouin light-scattering spectroscopy, we experimentally demonstrate the transport of spin waves along the asymmetric 3D coupler. Additionally, by employing experimental techniques, we explore the nonreciprocal propagation of spin waves in the considered structure by reversing the polarity of the external magnetic field. To gain further insights, we employ micromagnetic modeling and the finite-element method to obtain the eigenmode spectra of the asymmetric 3D coupler. Our results show that reversing the polarity of the external magnetic field induces coupling between the magnetic stripes. We elucidate the characteristics of lateral and vertical spin-wave transport, as well as nonreciprocal spin-wave propagation within the investigated structure. Notably, in the asymmetric 3D coupler, the coupling length diminishes, offering the potential to enhance the density of functional elements in the design of three-dimensional magnonic networks.

A study of spin wave spectra in a two-layer structure of iron-yttrium garnet (YIG) with different magnitudes of the saturation magnetizations of the layers has been carried out. Different modes of spin wave propagation (reciprocal, nonreciprocal, single-wave) depending on the type of structure and width of the central waveguide are investigated. The classification of spin wave spectra is carried out, and the class of guided, outgoing, and edge spin modes is identified. In particular, it is shown that in a system of planar magnetic comb-type LS-type (Ms1 Ms2) microwave guide tubes with periodic boundary conditions, two non-contiguous frequency regions of existence of guided modes of the central waveguide are observed for a width w of the central waveguide. Two adjacent frequency regions exist in the system of planar magnetic comb-type HS-type (Ms1 Ms2) microwave guide tubes at any values of the width of the central waveguide: in the high-frequency region, the mode with outflowing modes of the structure is realized, while in the low-frequency region, the mode with guided modes of the central waveguide is realized. It is shown that in systems of both types in the region of strongly inhomogeneous magnetic fields there can exist modes of boundary waves having a mutual character of propagation. The results obtained can be used to expand and clarify the physics of wave processes in complicated magnetic structures.

Purpose. Investigation of the joint manifestation of the effects of anisotropic signal propagation, coupling, and nonlinear power dependence of the medium parameters in a lattice of laterally and vertically coupled spin-wave (SW) microwaveguides. Consideration of the case of the influence of the rotation of the magnetization angle and the change of the lateral gap between microwaveguides located on the same substrate on the transverse profile of the spin-wave beam and the spatial localization of the SW amplitude. Methods. The method of micromagnetic modeling based on the numerical solution of the Landau–Lifshitz–Hilbert equation shows the possibility of controlling the direction of propagation of SW in an ensemble of laterally and vertically coupled iron yttrium garnet (YIG) microwaveguides by changing the magnetization angle. By the method of numerical integration of the system of coupled discrete nonlinear Schrodinger equations, the possibility of changing the transverse profile of the spin-wave beam by changing the level of the initial signal amplitude is shown. Results. The spatial distributions of the components of the dynamic magnetization of the SW excited in two microwaveguides located on the same substrate obtained in micromagnetic simulations indicate a change in the character of localization of the SW power in the output sections of the microwaveguides. At variation of the lattice magnetization angle, a shift of the threshold power value is observed, at which a characteristic curbing of the transverse width of the spin-wave beam in the nonlinear mode appears. Conclusion. When excitation of surface magnetostatic SW in a lattice of laterally and vertically coupled microwaveguides, a transformation of the transverse profile of the wave is observed at a deviation of the magnetization angle of the structure by 15º , which is manifested in the change of the SW length and its localization in each of the microwaveguides. The combined effects of dipole coupling, gyrotropy, and nonlinearity of the medium make it possible to control the value of the threshold power of the SW, at which the mode of diffractionless propagation of the spin-wave beam is realized in a single layer of the structure.

In this work, we demonstrate the numerical and experimental research of the spin-wave transport in a structure composed of a gallium arsenide (GaAs) stripe lattice interfaced to an yttrium iron garnet layer. We show that this structure can be considered as an array of an infinite number of laterally coupled ferrite-semiconductor waveguides. We show that the surface wave properties for colinear propagation along the semiconductor stripes are similar to the waves in magnetic films with partial metallization. In addition, the properties of these surface waves depend on the electron concentration of the GaAs and thus may be tuned. With regard to the wave propagation at a certain angle to the GaAs stripe lattice, the Bragg resonance forms and the corresponding band gap depend on the angle between the wave to the stripes and on the GaAs electron density. The Brillouin light scattering technique was used to experimentally observe the spin-wave beam transformation, and microwave measurements support the numerical data and reveal the mechanism of the dip formation and widening of the frequency range in the spin-wave transmission. The proposed structure could be used as a reconfigurable metasurface and magnonic beam separation unit.

Here we propose the different simple building block of the three-dimensional (3D) magnonic network in the form of the joined orthogonal sections of magnonic waveguides. It was shown, that the proposed 3D structures allows the transmission of spin-wave signals in the regime of surface magnetostatic wave propagation without the significant losses due to the junction region. Micromagnetic simulation was used to reveal the mechanism of spin-wave propagation across 3D junction. An electrodynamic problem is considered by the finite element method and the dispersion characteristics of spin waves (SW) are constructed with a change in the geometric parameters of the meander. The nature of the change in the frequency ranges of the Bragg band gaps depending on the meander profile has been studied in detail. It was demonstrated that spin-wave waveguiding 3D structure with broken translational symmetry exploiting the vertical spin-wave transport provides the transmission of the information signal in three-dimensional configuration of magnonic networks.

A meander waveguide made of an yttrium iron garnet (YIG) film with variation of the profile is studied with a view to the possible control of band bands for surface spin waves (SSWs). The finite element method is used to determine the control mechanism of forbidden band gaps in thin YIG films. The electromagnetic problem is solved, and the dispersion characteristics of spin waves are plotted for various geometrical parameters of the meander. The nature of the change in the frequency ranges of Bragg forbidden band gaps is studied in detail depending on the profile of the meander. It is demonstrated that a three-dimensional spin-wave structure with broken translational symmetry that uses vertical spin-wave transport provides an information signal transmission in a three-dimensional configuration of magnonic networks.

The possibility of frequency-selective propagation of spin waves in a magnonic microwave guide with a magnonic crystal consisting of two layers with different values of the saturation magnetization in the layers is demonstrated. It is shown that multimode propagation of spin waves can occur inside a two-layer structure in two frequency ranges, while the presence of a magnonic crystal on the surface of the structure leads to the manifestation of a band gap in one of the frequency ranges. At the same time, the process of propagation of a spin-wave signal is accompanied by a strong nonreciprocity, which manifests itself in a change in the amplitude-frequency characteristics when the direction of the external magnetic field is reversed, while the frequency range of the band gap differs depending on the direction of the field. The proposed concept of a two-layer spin-wave waveguide can underlie the manufacture of multichannel filters or magnonic logic devices.

The possibility of frequency-selective propagation of spin waves in a magnonic microwave guide with a magnonic crystal consisting of two layers with different values of the saturation magnetization in the layers is demonstrated. It is shown that multimode propagation of spin waves can occur inside a two-layer structure in two frequency ranges, while the presence of a magnonic crystal on the surface of the structure leads to the manifestation of a band gap in one of the frequency ranges. At the same time, the process of propagation of a spin-wave signal is accompanied by a strong nonreciprocity, which manifests itself in a change in the amplitude-frequency characteristics when the direction of the external magnetic field is reversed, while the frequency range of the band gap differs depending on the direction of the field. The proposed concept of a two-layer spin-wave waveguide can underlie the manufacture of multichannel filters or magnonic logic devices. Keywords: magnonics, nonlinearity, nonlinear systems, multilayer systems, spin waves.

The present work is devoted to the study of the optically induced formation of the band structure of a magnon crystal consisting of a ferrite microwave diode loaded with a semiconductor with periodic thickness modulation. Using the Brillouin light scattering method, it is demonstrated that an increase in the power of laser radiation illuminating the semiconductor layer leads to the formation of non-transmission bands in the spectrum of surface magnetostatic waves (PMSW) with a simultaneous increase in the central frequency of these bands. Using the finite element method, we connected the formed non-transmission bands with the Bragg resonances of the periodic structure, and also evaluated the effect of changes in the density of semiconductor electrons on the dispersion dependences and non-reciprocal properties of PMSV in such a structure.

Numerical micromagnetic modeling is used to analyze regimes of the propagation of spin waves in arrays of microwaveguides whose configuration corresponds to the excitation of two central channels of a surface layer or backward volume-type magnetostatic spin waves. It is shown that the proposed structure selects the spatial frequency of a signal with an efficiency that depends on the mutual orientation of the bias magnetic field and the direction of wave propagation.

We demonstrate the laser-induced control over spin-wave (SW) transport in the magnonic crystal (MC) waveguide formed from the semiconductor slab placed on the ferrite film. We considered bilayer MC with periodical grooves performed on the top of the n-type gallium arsenide slab side that oriented to the yttrium iron garnet film. To observe the appearance of magnonic gap induced by laser radiation, the fabricated structure was studied by the use of microwave spectroscopy and Brillouin light-scattering. We perform detailed numerical studies of this structure. We showed that the optical control of the magnonic gaps (frequency width and position) is related to the variation of the charge carriers' concentration in GaAs. We attribute these to nonreciprocity of SW transport in the layered structure. Nonreciprocity was induced by the laser exposure of the GaAs slab due to SWs' induced electromagnetic field screening by the optically-generated charge carriers. We showed that SW dispersion, nonreciprocity, and magnonic band gap position and width in the ferrite-semiconductor magnonic crystal can be modified in a controlled manner by laser radiation. Our results show the possibility of the integration of magnonics and semiconductor electronics on the base of YIG/GaAs structures.

Методом численного моделирования показана возможность управления направлением распространения спиновых волн в ансамбле латерально и вертикально связанных микрополосок железо-иттриевого граната (ЖИГ). С помощью метода конечных элементов проведен расчет величины длины связи спиновых волн в латеральной и вертикальной геометриях. Численное значение коэффициентов связи спиновых волн находилось методом конечных элементов в результате решения системы уравнений Максвелла с тензором магнитной проницаемости полученным из линеаризации уравнения Ландау--Лифшица. Методом интегрирования уравнения связанных волн показана возможность изменения направления распространения спин-волнового сигнала в рассматриваемой структуре. Полученные в микромагнитном моделировании спектры прохождения сигнала свидетельствуют об изменении характера локализации мощности спиновой волны в выходных секциях микроволновода при изменении частоты на входе структуры. Система латерально и вертикально связанных микроволноводов представляет собой элемент межсоединений для трехмерных топологий магнонных сетей, демонстрируя при этом функциональные возможности пространственно-частотного демультиплексирования сигнала. Ключевые слова: спиновые волны, магноника, латеральные структуры, магнонный кристалл, ансамбли связанных структур.

The dynamics of spin waves during their multimode propagation in a magnonic crystal, which is an irregular narrow ferrite waveguide with periodic boundary modulation, has been studied by the method of Mandelstam--Brillouin spectroscopy. The transformation of the mode composition of spin waves propagating in an irregular ferrite waveguide is shown. The space-time dynamics of spin waves and the characteristics of the band gaps of a magnonic crystal are experimentally studied, and the possibility of controlling the frequency-selective properties of such a structure is shown. By excitation of a superposition of even or odd width modes of the ferrite microstructure, it becomes possible to control the position of the band gaps of a magnonic crystal. The results of the experiment agree with the results of micromagnetic modeling of the propagation and transformation of the spectrum of spin waves propagating in a ferromagnetic periodic structure. Keywords: spin waves, magnonics, magnonic crystal, micromagnetic modeling.

Objectives. Nonreciprocal spin wave effects can manifest themselves in metalized films of ferrite garnets. By studying the dynamics of spin waves in micro- and nano-scale magnetic films, the possibility of using multilayer dielectric films of yttrium iron garnet (YIG) to ensure the manifestation of the nonreciprocity effect is demonstrated. This approach offers advantages compared to the use of a layered YIG/metal structure due to significantly lower spin-wave losses in the two-layer YIG film consisting of layers with different values of magnetization. Such films can be used in logical elements to create controllable Mach-Zehnder interferometers based on magnonic principles. The purpose of this work is to reconcile the concept of nonreciprocal spin-wave propagation of a signal with the simultaneous manifestation of the effects arising from the propagation of spin waves in microwave guides formed by finite-width YIG films.Methods. We used an experimental microwave spectroscopy method based on a vector network analyzer along with a finite difference method to perform a numerical simulation of the dispersion characteristics of spin waves in two-layer magnonic microwave guides. An analytical model was also used to obtain a dispersion equation based on the magnetostatic approximation.Results. Based on measurements of the amplitude and phase responses, the possible coexistence of two frequency ranges for the propagation of a spin-wave signal in a two-layer magnon microwave guide based on a YIG film formed by two layers with different values of saturation magnetization was demonstrated. Regimes of nonreciprocal propagation of a spin-wave signal were revealed. A numerical model was using to study the formation mechanisms of spin wave modes in the spectrum of a two-layer structure formed due to the finite dimensions of the microwave guide. An analytical model was used to evaluate the transformation of the mode spectrum. The experimental data are in good agreement with the results of the proposed numerical and analytical models.Conclusions. The possibility of frequency-selective propagation of spin waves in a magnon microwaveguide consisting of two layers with different saturation magnetization values is demonstrated. Multimode propagation of spin waves can occur inside a two-layer structure in two frequency ranges. At the same time, this process is accompanied by a strong nonreciprocity of spin-wave signal propagation, which manifests itself in a change in the amplitude and phase responses when the direction of the external magnetic field is reversed. The proposed two-layer spin-wave waveguide concept can be used in the manufacture of magnon interconnects and magnon interferometers with the support of multiband regimes of operation.

In this work, we will reveal the regularities in the control of the dipole spin-wava spectra of in lateral heterostructures formed from two magnonic crystals with a piezoelectric layer placed on one of them. The electric field control of the spatial and transfer characteristics of dipole spin waves in lateral heterostructures is shown. Based on the finite element method, the influence of distributed elastic deformations on the magnitudes of internal magnetic fields in magnonic crystals is evaluated. Based on the results of numerical simulations, a physical interpretation of the transformation of the eigenmode spectrum of coupled magnon crystals is given. Keywords: spin waves, magnonics, straintronics, lateral structures.

Coupled waves are used to study the effect the nonreciprocal propagation of spin waves and the magnitude of coupling have on the resonant frequencies of coupled Fabry–Pérot resonators loaded with conducting layers. It is shown that an increase in the nonreciprocity of the propagation of spin waves and the magnitude of the coupling of the results in splitting of the resonant frequencies of the system and shifting them to a region of higher frequencies. Results in this work can be used to create multichannel frequency-selective information signal processing devices based on the principles of magnonics.

In this work, we will reveal the regularities in the control of the dipole spin-wava spectra of in lateral heterostructures formed from two magnonic crystals with a piezoelectric layer placed on one of them. The electric field control of the spatial and transfer characteristics of dipole spin waves in lateral heterostructures is shown. Based on the finite element method, the influence of distributed elastic deformations on the magnitudes of internal magnetic fields in magnonic crystals is evaluated. Based on the results of numerical simulations, a physical interpretation of the transformation of the eigenmode spectrum of coupled magnon crystals is given.

The possibility of frequency-selective propagation of spin waves in a linear and nonlinear mode in a magnon microwave medium consisting of two layers with different values of the magnetization saturation of each layer is demonstrated. It is shown that multimode propagation of spin waves can be carried out inside the two-layer structure in two frequency ranges, with an increase in the power of the input microwave signal leading to a change in the boundaries of both frequency ranges. At the same time, this process is accompanied by a strong nonreciprocity of the spin-wave signal propagation, which manifests itself in a change in the amplitude-frequency characteristics when the direction of the external magnetic field is reversed, with a nonlinear mode change in the frequency bandwidth borders can change with increasing pumping power. The proposed concept of a two-layer spin-wave waveguide can form the basis for the fabrication of nonlinear magnon elements demonstrating interconnection functions with support for multiband modes of operation

The dynamics of spin waves during their multimode propagation in a magnonic crystal, which is an irregular narrow ferrite waveguide with periodic boundary modulation, has been studied by the method of Mandelstam-Brillouin spectroscopy. The transformation of the mode composition of spin waves propagating in an irregular ferrite waveguide is shown. The space-time dynamics of spin waves and the characteristics of the band gaps of a magnonic crystal are experimentally studied, and the possibility of controlling the frequency-selective properties of such a structure is shown. By excitation of a superposition of even or odd width modes of the ferrite microstructure, it becomes possible to control the position of the band gaps of a magnonic crystal. The results of the experiment agree with the results of micromagnetic modeling of the propagation and transformation of the spectrum of spin waves propagating in a ferromagnetic periodic structure.