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.

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.

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.

In a structure of an epitaxial film of yttrium iron garnet (YIG) with crystallographic orientation (111) 11.8 μm thick and a 5 nm thick platinum (Pt) film deposited on its surface, the effect of EMF generation in a platinum film during the propagation of magnetostatic waves (MSW) in the structure was studied at values of the tangential constant magnetic field H less than the saturation field H_s~65 Oe of the YIG film. The experiments were performed in a geometry where the field H was parallel to the crystallographic direction [1¯21] and to the MSW antennas, and the distances from the input antenna to the output antenna and to the Pt film were ~5 mm and ~0.5 mm, respectively. In the structure under consideration, at |H|<H_s, a stripe domain structure (SDS) was formed, which in fields |H|<H_1~5 – 7 Oe acquired a branching character in the near-surface layer. In the range of fields H_1<|H|<H_2≈40 Oe, MSW propagation was observed in the frequency band ∆F_1~ 300-550 MHz, which was accompanied by EMF generation due to the inverse spin Hall effect. In the interval H_2<|H|≤H_s, MSW propagation was observed in the frequency band ∆F_2≈ 750-1750 MHz, while the frequency interval in which the EMF signal was recorded turned out to be several times smaller due to the development of MSW parametric instability.

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.

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.

The effect of EMF generation due to the inverse spin-Hall effect during the propagation of magnetostatic surface waves (MSSW) in the structure of yttrium iron garnet (YIG) --- platinum based on a two-layer YIG film with different saturation magnetizations of the layers ((4π M 1 >4π M 2 ) has been experimentally studied. It was shown that the magnitude of the EMF resonantly increases at the frequencies of hybridization of the MSSW with the exchange modes of the structure. At the same time, at the frequencies of the MSSW of the layer with a higher magnetization, oscillations of the EMF are observed, caused by its hybridization with the exchange modes of both the layer with 4π M 1 and the layer with lower magnetization, which indicates the influence of interlayer exchange on the efficiency of spin pumping in the structure under consideration. The influence of the interference of counterpropagating MSSWs on the generated EMF has been studied. It has been shown that the EMF value is sensitive to the phase difference between counterpropagating MSSWs and oscillates. In this case, the amplitude of the oscillations is determined by the ratio of the wavelength of the MSSW and the length of the platinum film. Keywords: magnetostatic waves, yttrium iron garnet, platinum, interference, inverse spin Hall effect.

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.

The effect of EMF generation due to the inverse spin-Hall effect during the propagation of surface magnetostatic waves (SMSW) in the structure of yttrium iron garnet (YIG) - platinum based on a two-layer YIG film with different saturation magnetizations of the layers ((4πM_1>4πM_2 ) has been experimentally studied. It was shown that the magnitude of the EMF resonantly increases at the frequencies of hybridization of the MSSW with the exchange modes of the structure. At the same time, at the frequencies of the MSSW of the layer with a higher magnetization, oscillations of the EMF are observed, caused by its hybridization with the exchange modes of both the layer with 4πM_1 and the layer with lower magnetization, which indicates the influence of interlayer exchange on the efficiency of spin pumping in the structure under consideration.The influence of the interference of counterpropagating MSSWs on the generated EMF has been studied.It has been shown that the EMF value is sensitive to the phase difference between counterpropagating MSSWs and oscillates.In this case, the amplitude of the oscillations is determined by the ratio of the wavelength of the MSSW and the length of the platinum film.

The purpose of this work is to find out the influence of three-magnon decay processes on the electromotive force (EMF (U)) generated by propagating magnetostatic surface waves (MSSW) with the help of the inverse spin Hall effect in the “yttrium-iron garnet (YIG) – platinum (Pt)” structure. Methods. The experiments were carried out using the delay line structures based on YIG films with the thickness of 8.8 and 14.6 µm, on the surface of which antennas were formed for MSSWs excitation and reception and a Pt film between antennas. Results. It was shown that the three-magnon parametric instability can significantly change the character of EMF dependences on frequency and on power of MSSW that resulted both from the effect of power limitation and from the participation of parametric spin waves (PSW) and secondary spin waves (SSW) in the processes of electron-magnon scattering on the YIG/Pt border. Conclusion. It was demonstrated that the effect of amplification of EMF generation at the frequencies that are close to the long-wavelength border of the MSSW spectrum is related with the PSW and SSW population of the region of anisotropic dipole-exchange spin waves spectrum, which is characterized by the presence of singularities in the magnon density of states (Van Hove singularities).

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 by used antennas. We studied the methods to construct a "majority" logic gate based on the interference of caustics of spin waves excited by the rectilinear transducers directed at an angle to the in-plane magnetic field. We propose an approach when adding a reference signal with fixed initial phase to three information signals allows to use an amplitude detector at the output of the device to built a truth table. 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. Keywords: spin waves, magnetic field, ferromagnetic films, permalloy.

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.

Topic. Micromagnetic modeling of the propagation of backward volume magnetostatic waves (MSBVW) beams, excited by an antenna, placed in the center of yttrium iron garnet (YIG) film, has been carried out. Aim. To explore MSBVW-beam focusing with an increase in the amplitude of the exciting field at the antenna under conditions when only four-magnon (4M) processes are allowed for the MSBVW. Methods. The problem was solved using micromagnetic modeling by the finite-difference method solving the Landau-Lifshitz equation using the OOMMF software package. Results. It is shown that, depending on the position of the signal frequency in the MSBVW spectrum, an increase in the amplitude of the input signal above a certain threshold can lead to both the effect of wave beam focusing due to the development of modulation instability and the spatiotemporal chaotization of the amplitude distribution in the beam due to 4M decay processes. Changing of MSBVW-beam instability character at the frequency variation is associated with a change in the angular spectrum width of the beam and interaction between MSBVW and so-called "width" modes of the film. The obtained results can be used to analyze the effects of the propagation of nonlinear spin waves in YIG film waveguides.

Аннотация.Тема.Проведено микромагнитное моделирование распространения волновых пучков обратных объемных магнитостатических волн, возбуждаемых антенной, помещенной в центре пленки железоиттриевого граната

In this paper, it is shown that in the n-InSb/YIG/GGG (YIG is yttrium iron garnet, GGG is gadolinium gallium garnet) structure, when the geometry of magnetization is tangential to the substrate plane (H < 10 kOe) and temperature T ≈ 300 K, the effect of negative magnetoresistance of about 1% appears, whereas in the n-InSb/GGG structure with the same geometry of magnetization, the magnetoresistance is positive (increase in electrical resistance in the magnetic field). The effect of negative magnetoresistance in the InSb/YIG/GGG structure is stipulated by the effect of the YIG magnetization on the conduction electrons of InSb (proximity effect) with the impact value determined by the YIG magnetization value and the InSb film parameters.