A5084230124- Magnetic properties of thin films
- Magneto-Optical Properties and Applications
- ZnO doping and properties
- Quantum and electron transport phenomena
- Magnetic Properties and Synthesis of Ferrites
- Magnetic Properties and Applications
- Physics of Superconductivity and Magnetism
- Theoretical and Computational Physics
- Semiconductor Quantum Structures and Devices
- Multiferroics and related materials
- Photonic Crystals and Applications
- Metallic Glasses and Amorphous Alloys
- Electromagnetic wave absorption materials
- Diamond and Carbon-based Materials Research
- Chemical and Physical Properties of Materials
- Noncommutative and Quantum Gravity Theories
- Phase-change materials and chalcogenides
- Semiconductor materials and interfaces
- Quantum Mechanics and Applications
- Semiconductor materials and devices
- High-pressure geophysics and materials
- Thin-Film Transistor Technologies
- Carbon Nanotubes in Composites
- Surface Roughness and Optical Measurements
- Characterization and Applications of Magnetic Nanoparticles
Ioffe Institute
2010-2022
ITMO University
2020
NS Kurnakova Institute of General and Inorganic Chemistry
2020
Saint Petersburg Academic University
2020
Physico-Technical Institute
2001-2019
Nagoya University
2016
Immanuel Kant Baltic Federal University
2016
St Petersburg University
2014
Russian Academy of Sciences
2001-2011
Pulsed laser deposition has been used to grow thin (10–84 nm) epitaxial layers of Yttrium Iron Garnet Y3Fe5O12 (YIG) on (111)–oriented Gadolinium Gallium substrates at different growth conditions. Atomic force microscopy showed flat surface morphology both micrometer and nanometer scales. X-ray diffraction measurements revealed that the films are coherent with substrate in interface plane. The interplane distance [111] direction was found be by 1.2% larger than expected for YIG...
We have clarified the origin of magnetically dead interface layer formed in yttrium iron garnet (YIG) films grown at above 700{\deg}C onto gadolinium gallium (GGG) substrate by means laser molecular beam epitaxy. The diffusion-assisted formation a Ga-rich region YIG / GGG is demonstrated composition depth profiling performed X-ray photoelectron spectroscopy, secondary ion mass spectroscopy and neutron reflectometry. Our finding sharp contrast to earlier expressed assumption that Gd acts as...
We describe synthesis of submicron Y3Fe5O12 (YIG) films sputtered on Si substrates and present results the investigation ferromagnetic resonance (FMR) spin waves in YIG/SiO2/Si structures. It is found that decrease annealing time leads to essential reduction FMR linewidth ΔH and, consequently, relaxation losses waves. Spin-wave propagation in-plane magnetized structures studied. observe asymmetry amplitude-frequency characteristics Damon-Eshbach caused by different localizations at free YIG...
We have studied the electron transport in ${\text{SiO}}_{2}(\text{Co})/\text{GaAs}$ and ${\text{SiO}}_{2}(\text{Co})/\text{Si}$ heterostructures, where ${\text{SiO}}_{2}(\text{Co})$ structure is granular ${\text{SiO}}_{2}$ film with Co nanoparticles. In heterostructures giant magnetoresistance effect observed. The has positive values, expressed when electrons are injected from into GaAs semiconductor, temperature-peak-type character. temperature location of depends on concentration can be...
We describe the synthesis of submicron Y3Fe5O12 (YIG) films sputtered on GaN-based substrates and present results investigation ferromagnetic resonance (FMR) spin wave propagation in YIG / GaN structures. It is found that waves propagated deposited have low damping. At frequency 3.2 GHz spin-wave damping parameter less than . Sputtered magnetic inhomogeneity, which gives main contribution to FMR linewidth. The linewidth increase caused by relaxation process insignificant equal values...
Synthesis of nanosized yttrium iron garnet (Y3Fe5O12, YIG) films followed by the study ferromagnetic resonance (FMR) and spin wave propagation in these is reported. The YIG were grown on gadolinium gallium substrates laser molecular beam epitaxy. It has been shown that waves propagating deposited at 700 °C have low damping. At frequency 3.29 GHz, spin-wave damping parameter less than 3.6 × 10−5. Magnetic inhomogeneities give main contribution to FMR linewidth. relaxation processes linewidth as 1.2%.
Spin-wave bandpass filters with small sizes on the basis of thin Y3Fe5O12 [yttrium-iron garnet (YIG)] films Gd3Ga5O12 [gadolinium-gallium (GGG)] and SiO2/Si substrates have been constructed. A YIG film a thickness 0.8μm has grown by ion-beam sputtering. It is found that coplanar antenna structure can be successfully used to construct tunable small-sized narrowband based spin waves. The filter transmission characteristic nonreciprocity when direction energy propagation changes....
We have calculated the exchange interaction between electrons in accumulation electron layer semiconductor near interface and ferromagnet ferromagnet/semiconductor heterostructure. It is found that forms potential barrier for spin-polarized electrons. The height strongly depends on difference of chemical potentials ferromagnet. maximum temperature dependence due to existence localized states layer. In framework developed theoretical model, injection magnetoresistance effect observed...
Using microwave and spin wave spectroscopy measurements, we examine the recently discovered room temperature magnetoelectric (ME) Ni/BaTiO 3 nanocomposites (NCs) fabricated under uniaxial compression. Over compositional range explored, observe a significant variation in absorption spectrum of NCs as function Ni content. We argue that relative change (SW) group velocity is related to internal field determined from ferromagnetic resonance ME coupling coefficient evaluated by these samples....
We describe synthesis of submicron Y3Fe5O12 (YIG) films sputtered on GaAs-based substrates and present results the study ferromagnetic resonance (FMR), spin wave propagation interaction between excitations 2D electrons in interface layer YIG/AlOx/GaAs-heterostructures. It is found that contribution relaxation process to FMR linewidth about 3.6%–6.6% . The main YIG given by a magnetic profile inhomogeneity. Transistor structures with two-dimensional electron gas (2DEG) channels AlOx/GaAs...
We have studied dielectric and magnetic losses in granular structures constituted by ferromagnetic nanoparticles (Co, Fe, B) an insulating amorphous a-SiO2 matrix at microwave frequencies, relation to metal concentration, substrate temperatures gas content, the plasma atmosphere sputtering annealing. The are due fast spin relaxation of nanoparticles, which becomes more pronounced with decreasing content occur via simultaneous changes granule direction polarization electrons on exchange-split...
Evolution of magnetic excitations from purely magnetostatic modes to dipole-exchange spin waves in the Damon–Eshbach geometry nanocomposite (SiO2)100−xCox (50 at. %<x<80 %) films during a transition superparamagnetic superferromagnetic state has been studied by Brillouin light scattering. It shown that removal degeneracy backward volume due nonzero exchange constant manifests itself more pronounced Stokes/anti-Stokes asymmetry. Accompanying static characterization means force...
We study spin excitations in thin magnetic films the Heisenberg model with dipole and exchange interactions by operator diagram technique make comparison of their parameters characteristics waves thick films. Dispersion relations (in two-dimensional monolayer bilayer lattices) spin-wave resonance spectrum $N$-layer structures are found. For films, determined simultaneous solution generalized Landau-Lifshitz equations equation for magnetostatic potential. Generalized derived from first...
We have studied losses of microwave electromagnetic radiation in granular amorphous hydrogenated carbon films a-C:H(Co) containing cobalt nanoparticles at concentrations below the percolation threshold and region. The difference between experimental values structures sputtered on corundum-based substrates those aramide tissues is observed. It found that this determined by localization sizes cluster electron states films. grow with increasing concentration frequency. frequency dependence fast...
Behavior of dipole-exchange spin waves (SWs) in the Damon-Eshbach geometry a nanocomposite ${({\text{SiO}}_{2})}_{100\ensuremath{-}x}{\text{Co}}_{x}$ superferromagnetic $(x=80\text{ }\text{at}\text{.}\text{ }%)$ film has been studied by Brillouin light scattering. The measured value effective exchange constant turned out to be three times less than its for bulk cobalt. A qualitative theoretical model proposed explain this reduction. It shown that ``superspin'' approximation, identifying each...
Nickel ferrite (NiFe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> , NFO) films were grown at high temperatures on SrTiO xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> (001) substrates using laser molecular beam epitaxy. A spinel lattice structure, with parameters close to those of bulk NFO, was confirmed by electron and X-ray diffraction. Vibrating sample magnetometer...
We investigate the composition dependence of microwave properties a series cold-pressed powder compacts prepared from nanoparticles ZnO, Ni, Co, and γ-Fe2O3 using microstrip line method spin wave spectroscopy (SWS). The spectra these magnetic nanocomposites (NCs) are found to possess double-peak behavior in losses over 2–16GHz frequency range. observed effect is most likely due oxygen-containg species that were adsorbed at surface NC leading core/shell structured nanoparticles. relative...
We describe the synthesis of nanosized Y3Fe5O12 (YIG) films grown by laser-molecular-beam epitaxy on Gd3Ga5O12 (GGG) and Nd3Ga5O12 (NdGG) substrates with (111) orientation present results ferromagnetic resonance (FMR) spin-wave propagation studies in these heterostructures. It is found that magnetic parameters YIG NdGG GGG are considerably different. FMR spectra YIG/NdGG structures characterized a large number narrow peaks, while YIG/GGG consist small peaks or one peak. The effective...
Heterostructures of silicon dioxide films containing cobalt nanoparticles SiO2(Co) grown on GaAs substrate exhibit at room temperature high values magnetic field enhancement photocurrent in the vicinity and above bandgap ∼1.4 eV. For photon energies E bandgap, significantly increases, while avalanche process is suppressed by field, current flowing through heterostructure decreases. The enhanced SiO2(Co 60 at. %)/GaAs H = 1.65 kOe a factor about ten for energy 1.5 This phenomenon explained...