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.

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.

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.

Spectral optical properties of synthesized ceramic nanoporous membranes based on anodic aluminum oxide coated silver in saturated ammonia gas flow have been experimentally investigated. Based on the measured transmission spectra and detected interference part of the spectra in wavelength range from 550 to 900 nm, temporal and spectral dependencies of the effective optical thickness and its changes in non-equilibrium conditions were obtained due to adsorption of ammonia molecules on silver film surface. According to detected and measured interference maximum shifts up to 14 nm in transmission spectra of Al2O3 + Ag membranes in ammonia gas flow, the possibility of constructing a selective interferometric optical sensors with 10 − 15 min response time is shown.

The spectrum of spin waves (SW) of tangentially magnetized films of yttrium iron garnet (YIG) with a surface metastructure in the form of gratings of etched grooves with a period Λ close to the film thickness d (Λ~d) has been experimentally and numerically studied. It has been found that the spectrum of the signal reflected from a microstrip transducer with a width w>>d,Λ located on the YIG film contains absorption lines associated with the excitation of the SW of the surface metastructure. In the case when the magnetic field H and the transducer are oriented along the grooves, the absorption lines of the metastructure are located at frequencies f* near the short-wavelength edge of the spectrum of the surface magnetostatic (Damon-Eshbach) wave fs. It is shown that f* linearly depends on H , which can be used to develop magnetic field sensors. The results of measurements of dependences f* (H) are in qualitative agreement with the results of micromagnetic modeling.

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.

It is shown that for the n-InSb/YIG/GGG (YIG - yttrium iron garnet, GGG - gallium-gadolinium garnet) structure in the tangent to the substrate plane geometry of magnetization (H <10 kOe) at a temperature T≈300 K the magnetoresistance of about 1% is negative, while for n-InSb/GGG structure, in the same magnetization geometry, the magnetoresistance is positive (an increase in electrical resistance in a magnetic field). The negative magnetoresistance effect in the InSb/YIG/GGG structure is due to the influence of the YIG magnetization on the conduction electrons of InSb (proximity effect) and the magnitude of the effect is determined by the value of YIG magnetization and parameters of InSb films.

The effect of elastic deformations on the ferromagnetic resonance spectrum of submicron polycrystalline films of yttrium iron garnet obtained by ion-beam sputtering on silicon and gallium arsenide substrates was studied. Magnetoelastic constants of the films on both substrates were calculated using the magnitude of the frequency shift of the absorption maximum in the ferromagnetic resonance spectrum. The value of constants did not exceed 16% of the known values for bulk polycrystalline garnet. The approach to increase the efficiency of electrical frequency tuning in composite multiferroic structures based on combination of static and dynamic (caused by the piezoelectric effect) deformations was proposed.

In the InSb film fabricated by thermal evaporation on the CdS single crystal, growth of reflection in the infrared region similar to plasma resonance in the single crystals has observed. Raman spectra demonstrate that the ratio of amorphous and crystalline phases is approximately constant for InSb films on the CdS substrate, which is not typical for the InSb film on gallium gadolinium garnet. The current – voltage characteristics of the InSb film on CdS as well as the annealed layer of InSb (core)–CdS (shell) quantum dots are linear and become sensitive to illumination.

The propagation of spin waves in an yttrium iron garnet film decorated by nickel film microstructures was experimentally and theoretically studied. It is shown that one can control the spin wave damping and form the spin wave beams by choosing geometry of the nickel microstructures.

The paper presents examples of the use of pulse force nanolithography, performed with a probe of an atomic force microscope, to form magnetic nanowires, nanocontacts, one- and two-dimensional arrays with characteristic dimensions of about 50-100 nm.

AbstractDependence of the texture tilt and excitation efficiency of shear waves on the working gas pressure in an interval of 0.14–0.74 mTorr that corresponds to the transition from collisionless to almost diffusion deposition is studied for the ZnO films with a thickness of about 0.45–1.2 μm that are synthesized in a planar dc magnetron system. It is shown that an increase in the pressure from about 0.14–0.24 to 0.74 mTorr causes a decrease in the tilt angle of the column texture from ~25°–27° to ~7° and a decrease in the efficiency of acoustic excitation. Films that are synthesized at pressures of ~0.14–0.24 mTorr close to the transition from the Townsend to glow discharge exhibit the highest excitation efficiency of shear waves. For such films, the insertion loss reaches a minimum level at thicknesses of 0.45–0.75 μm and the number of echo pulses amounts to 20–40, so that the reflected sound can be observed with a delay of up to 80 μs at a length of an acoustic guiding crystal of 10 mm.

© А.С. Джумалиев, Ю.В. Никулин, Ю.А. Филимонов 1,2,3 1 Саратовский филиал Института радиотехники и электроники им. В.А. Котельникова РАН, 410019 Саратов, Россия 2 Саратовский национальный исследовательский государственный университет им. Н.Г. Чернышевского, 410012 Саратов, Россия 3 Саратовский государственный технический университет им. Ю.А. Гагарина, 410054 Саратов, Россия е-mail: yvnikulin@gmail.com

Влияние материала металлического подслоя и геометрии осаждения на формирование текстуры в пьезоактивных пленках ZnO© А.Г.Веселов, 1 В

Затухание продольных и сдвиговых акустических волн в структуре с пленками ZnO с прямой и наклонной текстурами© А.Г.Веселов