A theoretical model is proposed that allows us to describe the processes of formation of the sputtered atom flow, transport of this flow in the target-substrate space and deposition of the substance onto the substrate during magnetron sputtering. The main difference between the presented model and the existing ones is the combined consideration of the spatial distribution of sputtered atoms and the temperature gradient in the working chamber during magnetron sputtering at high power. To verify the model, real technological parameters of deposition of metal films by magnetron sputtering were used, optimized to achieve a high film growth rate. The agreement between the calculated film thicknesses obtained as a result of modeling and the experimental data was no worse than 5% at discharge powers in the range of 100 – 700 W. Comparison of the experimental data with the simulation results showed that the model adequately describes the sputtering processes at high discharge powers and low pressures, in contrast to approaches that do not take into account the temperature gradient in the working space.

The purpose of this work is to experimentally study, using the inverse spin Hall effect (ISHE), the detection of focused beams of magnetostatic surface waves (MSSW) in integrated YIG (3.9 µm) / Pt (4 nm) thin-film microstructures, where the focusing effect was ensured by the curvilinear shape of the exciting antenna. Make a comparison with the case of detecting MSSWs excited by a rectilinear antenna. Methods. Experiments were carried out using the delay line structures based on the YIG/Pt. The amplitude-frequency characteristics of the YIG/Pt structure and the frequency dependence of the EMF (V(f)) induced in platinum were studied. Results. It was shown that at frequencies f near the long-wavelength limit of the MSSW spectrum, the magnitude of the EMF V(f) generated by a focused MSSW can be several times higher than the values of V(f) in the case of MSSW excitation by a common (straight) antenna. In this case, in the short-wavelength part of the spectrum, on the contrary, the magnitude of the EMF generated by the focused MSSW beam turns out to be noticeably smaller. This behavior is associated with chromatic aberration of the focusing antenna for the MSSW, which manifests itself in the frequency dependence of the focal length of the antenna, which is confirmed by the results of micromagnetic modeling. It is shown that the drop in the EMF signal generated by a focused MSSW beam in the short-wavelength part of the spectrum is associated with the focus reaching the area of the YIG not covered with the Pt film. In this case, the increase in V(f) in the long-wavelength region of the MSSW spectrum is explained by an increase in the linear power density of the MSSW and the formation of caustics under the Pt film. Conclusion. Obtained results can be used for the development of highly sensitive spin wave detectors and the creation of spin logic devices.

The spin pumping by traveling magnetostatic surface waves (MSSW) in two YIG/Pt structures corresponding to the cases of MSSWpropagation along the [100] direction (hard axis of magnetization) and [110] direction(easy axis of magnetization) has been studied using the inverse spin Hall effect (ISHE). It is shown that the cubic anisotropy field does not change the character of the frequency dependences of the electromotive force U ISHE (f), but for the [110] direction it leads to an increase in the signal U ISHE (f) and an upward shift in frequency by 410 MHz relative to the case of magnetization along the «hard» axis.

Spin pumping by surface and backward volume magnetostatic waves in YIG/Pt structures is experimentally studied and analyzed. It is shown that at frequencies corresponding to van Hove singularities in the density of states of the spin wave spectrum, an increase in the efficiency of electron-magnon scattering and spin current generation takes place. The obtained results are important for spin wave-based spintronic devices development.

The characteristics of EMF (U) generation in the thin-film Pt/YIG structures caused by hybridization of propagating magnetostatic surface waves with exchange modes of YIG film were studied. It was shown that at frequencies f* corresponding to the dipole-exchange resonances (DER) the magnitude of EMF U increases by several times in comparison with the frequencies different from DER (f?f*). The Volt-Watt sensitivity was estimated for the Pt/YIG structures with different geometries of Pt microstrips. Keywords: Spintronics, spin waves, EMF generation, electron drag effect , dipole-exchange resonance.

Background and Objectives: One of the main tasks for developing magnonic devices is to form and control spin wave beams. For this purpose, the decoration of ferrite films with magnetic or non-magnetic metal areas can be used. The aim of this work is to study the peculiarities of magnetostatic surface wave (MSSW) propagation in the channels formed in yttrium-iron garnet (YIG) films by deposition of 1.5 μm thick metal decorations from chromium (Cr) and permalloy (Py). Materials and Methods: Studied samples were fabricated on the base of 6.5 μm-thick epitaxial YIG film by the DC magnetron sputtering, photolithography, and ion etching techniques. Frequency dependencies of magnitude and phase of the transmitted MSSW signal at different applied magnetic field were measured with the help of a vector network analyzer and a microwave probe station. Calculation of the dispersions and insertion losses for MSSW propagating in the metallized YIG film was performed on the basis of Maxwell’s equations in the magnetostatic approximation, the Landau-Lifshitz equation, and standard electrodynamic boundary conditions. Results and Conclusion: The optimal channel width w relative to the antenna aperture providing channeling of the MSSW signal with the possibility of “antireflective effect” for the transmitted signal has been found to be w = 200 μm. It has been shown that for the formation of channeling effect, one needs to use a non-magnetic metal with the thickness leading to a transition to the “metallic” branch of the MSSW dispersion or a magnetic metal with the thickness resulting in bending of a short-wavelength part of MSSW dispersion. For the studied samples, it is d(Cr) = 1.5 μm and d(Py) = 30 nm, respectively. The obtained results demonstrate the possibility of using the channels in metallic decorations for the formation of directed spin wave beams.

Using the inverse spin hall effect, a study of spin pumping by running magnetostatic surface waves in YIG/Pt microstructures was carried out, where an Fe application was used as a source of a local non-uniform magnetic field. The results of measuring the frequency dependences of the EMF are presented. It is shown, that the Fe application leads to an upward shift in frequency and «bluring» of the EMF peak near the lo-frequency boundary of the magnetostatic surface waves – its width increases, the amplitude decreases compared to the case of the YIG/Pt structure without the application.

Spin pumping by traveling magnetostatic surface waves (MSSW) has been experimentally investigated in YIG|Pt structures made on the basis of 0.9, 4, 8, 14 and 18 µm thick YIG epitaxial films. It is found that at frequencies corresponding to the van Hove singularities in the density of states of the MSSW spectrum of the structure, the EMF value generated due to the inverse spin Hall effect increases. This increase is associated with an increase in the spin mixing conductance of the YIG|Pt interface due to an increase in the efficiency of electron-magnon scattering at the frequencies of van Hove singularities in the spin wave spectrum.

Spin pumping by traveling magnetostatic surface waves (MSSW) has been experimentally investigated in YIG|Pt structures made on the basis of 0.9, 4, 8, 14 and 18 μm thick YIG epitaxial films. It is found that at frequencies corresponding to the van Hove singularities in the density of states of the MSSW spectrum of the structure, the EMF value generated due to the inverse spin Hall effect increases. This increase is associated with an increase in the spin mixing conductance of the YIG|Pt interface due to an increase in the efficiency of electron-magnon scattering at the frequencies of van Hove singularities in the spin wave spectrum. Keywords: spintronics, spin transport, spin waves, magnon density of states.

Experimental results on the magnetostatic surface wave (MSSW) propagation in an yttrium-iron garnet film with a periodical array of metal stripes on the surface are presented. An effect of the pass bands formation in the MSSW transmission characteristics contrasting to the known Bragg stop bands inherent in a periodical structure is reported and discussed. Our findings provide one more way to affect the spin wave propagation and realize a control in magnonic devices.

Transmission of magnetostatic surface waves (MSSW) through the microchannels formed by decoration of yttrium-iron garnet (YIG) film with non-magnetic (chromium) and ferromagnetic (permalloy) metals having thickness of 30 nm was experimentally studied. MSSW losses induced by the considered metals and MSSW dispersion curves are compared with theoretical dependencies calculated taking into account the finite conductivity and magnetization of the metal layers. Possibility to reach the “antireflective” effect in the amplitude-frequency dependencies of MSSW transmission coefficient with the help of YIG film decoration with the permalloy elements was shown.

In this work, we consider the possibility of building a magnonic co-processor for special task data processing. Its principle of operation is based on the natural property of an active ring circuit to self-adjust to the resonant frequency. The co-processor comprises a multi-path active ring circuit where the magnetic part is a mesh of magnonic waveguides. Each waveguide acts as a phase shifter and a frequency filter at the same time. Being connected to the external electric part, the system naturally searches for the path which matches the phase of the electric part. This property can be utilized for solving a variety of mathematical problems including prime factorization, bridges of the Konigsberg problem, traveling salesman, etc. We also present experimental data on the proof-of-the-concept experiment demonstrating the spin wave signal re-routing inside a magnonic matrix depending on the position of the electric phase shifter. The magnetic part is a 3 × 3 matrix of waveguides made of single-crystal yttrium iron garnet Y3Fe2(FeO4)3 films. The results demonstrate a prominent change in the output power at different ports depending on the position of the electric phase shifter. The described magnonic co-processor is robust, deterministic, and operates at room temperature. The ability to exploit the unique physical properties inherent in spin waves and classical wave superposition may be translated into a huge functional throughput that may exceed 1060 operations per meter squared per second for 50×50 magnetic mesh. Physical limits and constraints are also discussed.

Using the inverse spin Hall effect (ISHE), spin pumping by traveling surface waves (MSSW) and backward volume waves (BVMSW) in YIG/Pt microstructures has been experimentally studied. It has been discovered that the frequency dependence of the emf UISHE(f), generated due to the ISHE, in the case of BVMSW is characterized by a maximum near the frequency of the long-wave (f0) spectrum boundary. In the case of a MSSW, the dependence UISHE (f) exhibits maxima both at the frequency f0 and at the frequency fs of the short-wave boundary of the MSSW spectrum. The indicated differences in the dependences UISHE (f) for MSSW and OOMSW are explained by the difference in the functions of the density of states of spin waves in the spectrum of MSSW and BVMSW.

The purpose of this work is to study the influence of four-magnon (4M) parametric instability on spin pumping by dipole-exchange magnetostatic surface waves (MSSW) with the help of the inverse spin Hall effect (ISHE) in structures based on yttrium-iron garnet (YIG) and platinum (Pt). Methods. The experiments were carried out using the delay line structures based on YIG(900 nm)/Pt(9 nm) where electromotive force (EMF) induced by ISHE demonstrates a growth at the frequencies of the resonant interaction between MSSW and volume exchange modes. The frequency dependencies of the amplitude and phase for the delay line structure and EMF (𝑈(𝑓)) from the platinum layer were studied as a function of the MSSW power. Results. It was shown that the resonant EMF growth at the frequencies of dipole-exchange resonances is caused by the presence of Van Hove singularities in the density of states for spin waves at such frequencies that leads to an increase in the efficiency of electron-magnon scattering at the YIG–Pt interface. A growth in MSSW power beyond the threshold of 4M instability development results in a “smoothing” of resonant particularities in the EMF frequency dependence 𝑈(𝑓) that can be explained by decreasing efficiency of spin pumping due to destruction of dipole-exchange resonances and related singularities in the density of states of spin waves. Conclusion. Obtained results may be of interest for the development of highly sensitive spin current detectors, as well as for the implementation of spintronic devices.

Both inverse spin Hall effect (“interface”) and electron drag by magnons (“bulk”) mechanisms of the electromotive force generation by travelling magnetostatic surface (MSSW) and backward volume (MSBVW) waves in YIG/Pt and YIG/n-InSb microstructures are studied. It is shown that “interface mechanism” plays the main role in YIG/ Pt bilayers, while for YIG/n-InSb structures, electron drag by magnons dominates. Giant oscillations of the voltage caused by inverse spin Hall effect were observed in YIG/Pt structures at frequencies corresponding to resonance interactions of MSSW with the volume exchange modes.

Using micromagnetic simulations, we show the possibility to build spin logic devices based on films of yttrium iron garnet and permalloy where energy channeling of spin waves is achieved due to excitation of focused and narrow-directed wave beams with used antennas. We studied the methods to construct a majority logic gate based on the interference of caustics of spin waves excited with the rectilinear transducers directed at an angle to the in-plane magnetic field. We propose the approach that allows using of amplitude detector to build a truth table and that consists in adding a reference signal with the fixed initial phase to three information signals. The possibility to scale the device on the example of its work in the range of spin waves with micron and submicron wavelengths is demonstrated.

With the help of micromagnetic modeling, we considered particularities of dispersions and amplitude-frequency response of spin waves in a magnonic crystal (MC) formed by etching an array of grooves in the surface of yttrium iron garnet film having linear distribution of magnetization across the thickness from 1.7 kG at the upper surface till 2.02 kG at the bottom. For the geometry of surface magnetostatic spin waves (MSSW), it is shown that nonuniformity of magnetization distribution across the thickness leads to the appearance of frequency regions in the MC spectrum where MSSW propagation is unidirectional and, as the consequence, does not have Bragg resonances. It was also demonstrated that the MC spectrum is determined by the choice of surface used for the formation of the array of grooves. Keywords: spin wave, micromagnetic modelling, film of yttrium iron garnet, magnonic crystal.

The results of study of bias voltage Ub and substrate temperature Ts influence on the texture of FeCo films with the thickness of 180 nm deposited on Si/SiO2 substrates by DC magnetron sputtering are presented. It is shown that the change of Ub from -250 V to 80 V leads to the growth of films with (110) texture. Further change of Ub from 80 V to 250 V causes the growth of films having (200) texture. Films deposited at Ub=0 and Ts=60-300oC have (200) texture. Further increase of Ts results in the change of film texture to (110). Keywords: FeCo films, magnetron sputtering, texture, coercitivity.

With the help of micromagnetic modeling, we considered particularities of dispersions and amplitude-frequency response of spin waves in a magnonic crystal (MC) formed by etching an array of grooves in the surface of yttrium iron garnet film having linear distribution of magnetization across the thickness from 1.7 kG at the upper surface till 2.02 kG at the bottom. For the geometry of surface magnetostatic spin waves (MSSW), it is shown that nonuniformity of magnetization distribution across the thickness leads to the appearance of frequency regions in the MC spectrum where MSSW propagation is unidirectional and, as the consequence, does not have Bragg resonances. It was also demonstrated that the MC spectrum is determined by the choice of surface used for the formation of the array of grooves.