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Publications (85)
Charged domain walls (CDW) in ferroelectric materials are interesting from fundamental and applied points of view, since they have electrical properties different from bulk ones. At the microstructural level, CDW in ferroelectrics are two-dimensional defects that separate regions of the material with different directions of spontaneous polarization...
Silicon-carbon films are of great interest as diamond-like materials combining unique properties – high hardness, adhesion to a wide class of materials, abrasion resistance, as well as chemical resistance, low coefficient of friction and biocompatibility. The presence of silicon in the composition makes it possible to significantly reduce the inter...
Magnetoelectric (ME) composites can be useful due to their wide range of possible applications, especially as sensors of weak magnetic fields at room temperature for magnetocardiography and magnetoencephalography techniques in medical diagnostic equipment. In most works on the topic of ME composites, structures are tested in uniform magnetic fields...
In this work the effect of annealing in a constant magnetic field on the magnetoelectric (ME) coefficient in three-layered gradient composites<LiNbO 3 /Ni/Metglas> is investigated. A technique of nickel electrochemical deposition on bidomain lithium niobate crystals was demonstrated. It is shown that the optimum temperature for the formation of the...
In the present work, we investigated the effect of prolonged exposure on the electrical conductivity of crystals with a charged domain wall (CDW) in congruent lithium niobate crystals (LiNbO3, LN) of a nonpolar x-cut. Bidomain ferroelectric structures containing charged head-to-head domain boundaries were formed in the samples using methods of diff...
Temperature and magnetic field dependencies of sheet resistance R # (T,B) in polycrystalline CVD graphene, investigated in the range of 2≤ T≤ 300 K and magnetic fields 0≤ B≤ 8 T, allowed to determine carrier transport mechanisms in single-layered and twisted CVD graphene. It is shown that for R # (T,B) curves for such samples are described by the i...
Lithium niobate (LiNbO3) and lithium tantalate (LiTaO3) are among the most important and most widely used materials of coherent and nonlinear optics, as well as acoustics. The strict requirements on the uniformity and reproducibility of characteristics have become the base of the industrial technology for the production of high-quality crystals, ma...
Lithium niobate (LN) is a ferroelectric material with a wide range of applications in optics and acoustics. Annealing of LN crystals in an oxygen-free environment leads to the appearance of black coloration and the concomitant increase in electrical conductivity due to chemical reduction. The literature presents many works on the study of the elect...
Ниобат лития (LiNbO3) и танталат лития (LiTaO3) относятся к важнейшим и наиболее широко применяемым материалам когерентной и нелинейной оптики, а также акустики. Высокие требования, предъявляемые к однородности и воспроизводимости характеристик, стали основой промышленной технологии выпуска высококачественных кристаллов, освоенной многими предприят...
Titanium alloys approved for clinical use in our country are widely used in traumatology, maxillofacial surgery and stomatology, mainly for the manufacture of various endoprostheses and dental implants, i.e. structures, introduced and installed in the bone and soft tissues of human body, able to both bio-integrate and bio-adaptable in the tissues o...
Titanium alloys approved for clinical application are used to manufacture various endoprostheses. Engraftment of the implant in bone tissue (osseointegration) is characterized by direct contact and functional connection between the implant and the bone tissue. The process of implant engraftment in soft tissue is characterized by fibrointegration, i...
We study the effect of the microtopography of the surface of titanium implants on the proliferation (reproduction process) of fibroblast-like cells (cells of the connective tissue of the body) using the morphological analysis of cell cultures by phase-contrast microscopy. Three-dimensional titanium cell matrices (scaffolds) are used as the mechanic...
The non-local dispersion of longitudinal ultrasonic waves is shown to appear in the heterogeneous solids due to continuous spatial distributions of their density and/or elasticity (gradient solids). This dispersion gives rise to the diversity of ultrasonic transmittance spectra, including the broadband total reflectance plateau, total transmission...
Lithium niobate films on silicon substrates were synthesized by high−frequency magnetron sputtering of a target. The resultant film was a layer of polycrystalline lithium niobate. By the method of spectrophotometry we obtained the spectral dependences of the reflectance in the wavelength range 300—700 nm at small angles of incidence. The angular de...
The comparative study of dielectric dispersion in thin LiNbO3 films deposited by radio-frequency (RF) magnetron sputtering and laser ablation on Si substrates was carried out. It was found that the dielectric permittivity of the lithium niobate films prepared by the various methods had the significant dispersion due to the barrier effects arising a...
In the current study, we have developed a mathematical model describing the frequency response of a sensor or energy harvester based on a cantilever made of a ferroelectric bidomain single-crystal plate with metal electrodes deposited on opposite faces. The structure is subjected to vibrational excitations. The model allows to predict the dependenc...
Titanium alloys approved for clinical use in Russia are widely used in traumatology, maxillofacial surgery, and stomatology, mainly for manufacturing various endoprostheses and dental implants, i.e., structures to be introduced and installed into the bone and soft tissues of the human organism, capable of both biointegration and bioadaptation in th...
Electrical, electromechanical, and structural–optical properties of films of vinylidene fluoride copolymer with tetrafluoroethylene TFE, doped with Rhodamine 6G dye, have been investigated. It is found that the conductivity increases in doped films; at the same time, it “anomalously” decreases with an increase in the field. The hysteresis loop of l...
the microstructure, value of self-polarization, and local piezoelectric hysteresis loops of LiNbO3 thin films synthesized on silicon substrates with a native SiOx layer and with a platinum layer are compared via scanning probe microscopy. It is found that smoother surfaces, smaller grain sizes, and a simultaneous higher self-polarization value and...
Vinylidene fluoride and tetrafluoroethylene copolymer 94/6 texturing has been carried out by one-axis drawing at Td = 75 °C up to the ratio of 6 with subsequent isometric tempering at 130 °C. Data of X-ray diffraction and IR-spectroscopy indicate partial polymorph transition from the metastable γ-phase to the polar β-modification with long segments...
LiNbO3 thin films with a thickness of 200 nm were deposited onto Al2O3 substrate by RF-magnetron
sputtering technique without intentional substrate heating. The results demonstrate that post-growth
infrared pulsed light annealing of the amorphous LiNbO3 films leads to the formation of two phases,
LiNbO3 and LiNb3O8. After annealing at temperatures...
The current work demonstrates examination of impact of annealing of lithium niobate films on their segnetoelectric properties. Thin LN films were grown on silicon wafer (with lots of layers including less than 1 µm Platinum layer on top) by RF magnetron sputtering (P=150 W, sputtering time-3 h, film thickness-300 nm). Roughness of both annealed and...
This paper presents the results of the study of the domain structure of barium titanate crystals in a wide temperature range including the Curie point (Tc) using the polarization-optical method in the reflected light and the force microscopy of the piezoelectric response. It is shown that a new a–c domain structure forms during cyclic heating of th...
In this paper, comprehensive investigation of the pyroelectric properties and local piezoelectric response in ferroelectric film heterostructures is presented. The pyroelectric effect is determined by the dynamic method and the pyroelectric response is recorded for further analysis. It is shown that such studies are effective to analyze the self-po...
The non-local dispersion of longitudinal ultrasonic waves is shown to appear in the heterogeneous solids due to continuous spatial distributions of their density and/or elasticity (gradient solids). This dispersion gives rise to the diversity of ultrasonic transmittance spectra, including the broadband total reflectance plateau, total transmission...
The features of using radioactive isotopes when creating off-line power supplies are considered. The analysis of the substances used in radioisotope thermoelectric generators (RTGs) is carried out. The prospects for manufacturing beta-voltaic generators are justified and they are compared with other electric power sources. The mechanism of β-decay...
Bidomain single crystals of lithium niobate (LiNbO3) and lithium tantalate (LiTaO3) are promising materials for use as actuators, mechanoelectrical transducers, and sensors capable of working in a wide temperature range. One need to take into account the anisotropy of the properties of the crystalline material when such devices are designed. In thi...
Lithium niobate films on silicon substrates have been synthesized by high-frequency magnetron sputtering of a target. The spectral dependences of the reflectance in the 300–700nm range at small incidence angles and the angular dependence of p- and s-polarized light for a discrete set of wavelengths from 300 to 700nm with wavelength increments of 50...
The anisotropic direct magnetoelectric (ME) properties of bi-layered composites comprising magnetostrictive metglas foils and single-crystalline piezoelectric bidomain plates of 127ºY-cut LiNbO<sub>3<sub> (LNO) have been studied theoretically and experimentally. The LNO plates possessed an engineered ferroelectric macrobidomain structure with oppos...
The crystallization of a copolymer from a solution at room temperature is found to lead to the formation of a metastable structure, characterized by the coexistence of ferroelectric and paraelectric phases. The fraction of the latter decreases after annealing above the Curie point. Atomic force microscopy (AFM) has revealed a difference in the surf...
The possibility of increasing the efficiency of a beta-voltaic generator due to using a single-crystal bimorph element made of lithium niobate as a piezoelectric converter. The known beta voltaic alternators consist of a piezoelectric cantilever and a source of β-electrons. The cantilever represents a resilient member made, for example, of silicon,...
This work is dedicated to the elucidation of surface dipole ordering in nanoscale thin polymer layers. The experimental study of submicron-film dielectric electroactive polydiphenylenephthalide polymer has revealed that it is composed of the side phthalide groups with a relatively large dipole moment. The interest in this polymer is due to the abno...
A hysteresis-free electrically controlled X-ray optical element based on a monolithic bi-domain bimorphic piezoelectric actuator that is made of lithium niobate crystal was proposed and successfully tested in practice. This element is used for electronically controlled adjustment of the angular position of an X-ray optical monochromator in a range...
Different sections of congruent lithium niobate (CLN) crystals have been studied using X-ray photoelectron spectroscopy (XPS). We have developed a method for measuring the lithium-to-niobium atomic ratio Li/Nb from the ratio of the Li1s and Nb4s spectral integral intensities with an overall error of within 8 %. Polarity and mechanical processing af...
The domain structure of lithium-niobate thin films grown on Si(111) and Si(100) substrates coated with a native oxide layer with a thickness of no less than 2 nm is investigated by X-ray diffraction, scanning electron microscopy and piezoresponse force microscopy. The films are synthesized by the rf magnetron sputtering of a single-crystal lithium-...
Bidomain single crystals of lithium niobate (LiNbO 3 ) and lithium tantalate (LiTaO 3 ) are promising material for usage as actuators, mechanoelectrical transducers and sensors working in a wide temperature range. It is necessary to take into account anisotropy of properties of crystalline material when such devices are designed. Inthis study we in...
The bidomain structures produced by light external heating in z-cut lithium niobate and lithium tantalate single crystals are formed and studied. Interdomain regions about 200 and 40 μm wide in, respectively, LiNbO3 and LiTaO3 bidomain crystals are visualized and studied by optical microscopy and piezoresponse force microscopy. Extended chains and...
A method of making given field distribution within thin electro-optical layers by using narrow band electrodes placed at the same electric potential. A formula for electric field intensity produced by a single band electrode is obtained. Electric field modeling for different band electrode configurations is undertaken. It was shown, by applying pie...
LiNbO3 thin films were deposited on Al2O3 substrates by RF-magnetron sputtering with in-situ electric field to study the self-polarization effect. The films have been characterized crystallographically by x-ray diffraction, and morphologically by atomic force microscopy. The films contain crystallites of LiNbO3 with preferable orientation [012] alo...
The interdomain region of a bidomain strucrture formed in 127°-cut lithium niobate single crystals using light annealing has been studied by optical and scanning probe microscopies. A periodic subdomain structure on the 180° macrodomain wall is visualized by piezoresponse force microscopy. The piezoresponse signal (polarization) is shown to be a po...
Temperature dependance of the resistivity of carbon−silicon 1 mkm film containing nanocise tungsten particles were investigated. Resistivity measurements were carried out by contact method in the temperature range 20—200 °С for films with resistivity at room temperature of about 0,03—15 Ohm cm. Decreasing of the resistivity with temperature was obs...
The angular dependence of the lateral component piesoresponse in Y−cut lithium niobate single crystals with a regular domain structure was investigated in piezoresponse force microscopy mode. It is shown that visualization of the domain structure is determined by the orientation of the X direction of the crystal relative to the scan direction: the...
The method of bidomain structure synthesis in lithium niobate single crystal wafers based on the formation of a specific temperature gradient across the sample thickness has been developed. The lithium niobate wafer placed between two silicon wafers was heated due to the absorption of light annealing system radiation by silicon. The work cell desig...
The characteristics of the local piezoelectric response of isotropic films of copolymers of vinylidene fluoride (VDF) were compared with 6 and 29 mol% tetrafluoroethylene (TFE) obtained by crystallization from a solution in acetone. Time dependence of the electric displacement response was analyzed after switching of the spontaneous polarization. A...
The method of development of the bidomain structure in single crystalline lithium niobate plates based on the creation of a given temperature gradient distribution through a sample thickness by stationary heating is considered. Heating the LiNbO3 plate, which is placed between two silicon plates, is implemented by light energy emitted by lamps of t...
The distribution of conductivity is studied in nanocristalline lithium niobate thin films via electrostatic force microscopy. Conductivity images are obtained at different bias voltages. Grain boundaries are shown to play a predominant role in the conductivity in lithium niobate thin films.
The poling and local piezoresponse mechanism has been investigated in ferroelectric
polymers. Isotropic 94/6 composition vinylidenefluoride and tetraflouroethylene copolymer films is
formed from acetone at room temperature by slow evaporation of solvent. The copolymer
crystallization results in metastability (nonequilibre) form at high overcooling...
In this work, scanning probe microscopy (SPM) in the so-called piezoresponse mode (PFM) is used to image the morphology, as-growth domain structure, domain wall motion and piezoelectric loop in lithium niobate thin films. A RF magnetron sputter system was used to deposit LiNbO3 thin films on (100)-oriented Si substrates with SiO2 layer. The surface...
We have studied the formation of thin textured LiNbO3 films in originally amorphous samples produced by rf magnetron sputtering of a single-crystal target on silicon substrates containing a native oxide layer. The results demonstrate that postgrowth annealing leads to the formation of two phases, LiNbO3 and LiNb3O8, and that the percentage of the n...
It has been shown that, in polycrystalline thin PZT films with the Zr/Ti = 0.535/0.465 ratio of ions in octahedral positions of the perovskite structure, the permittivity and the pyroelectric and piezoelectric responses increase with increasing linear sizes of growth blocks to reach anomalously large values. It has been assumed that the observed ef...
In this paper we report on using the atomic force microscope in piezoresponse and Kelvin modes to image grains, ferroelectric domains and surface potential in lithium niobate thin films. The radio frequency magnetron sputter system was used to deposit LiNbO3 thin films on (1 0 0)-oriented Si substrate with SiO2 layer. The surface of the sample show...
The surface topography and characteristics of a local piezoelectric-response signal in isotropic films of a ferroelectric vinylidene fluoride-tetrafluoroethylene copolymer with a composition of 94: 6 are studied via scanning probe microscopy. The X-ray diffraction and IR spectroscopy data indicate that crystallization occurs in a mixture of β and γ...
Electro-optic LiNbO3 thin films were deposited on Si(100) and Si(111) substrates using a radio-frequency magnetron sputtering process. The piezoelectric properties of the LiNbO3 films were investigated using the scanning probe microscopy in the piezoresponse mode. The obtained results show the high degree of grains orientation in polycrystalline st...
The temperature dependences of the specific electroconductivity of silicon-carbon films with nanosized tungsten inclusions were studied. The electroconductivity of specimens within a temperature range of 20–200°C was measured by the contact method. The electroconductivity of films with a room-temperature specific electroconductivity of 0.03-15 Ω cm...
The distributions of induced state and surface potential in thin lithium niobate films obtained via the deposition onto a (100)-oriented Si-oxidized substrate by the method of high-frequency magnetron sputtering were mapped using piezoresponse force microscopy (PFM) and Kelvin probe force microscopy (KPFM). Using an electrical field applied with a...
The local piezoelectric properties of ferroelectric composites consisting of P(VDF-TrFE) copolymer matrix with barium lead zirconate titanate ceramic inclusions were addressed both experimentally using piezoresponse force microscopy technique and theoretically applying the Landau-Ginzburg-Devonshire formalism. A transient region with a width of app...
Morphology of the surface and local ferroelectric properties of thin lead zirconate titanate (PZT) films synthesized by the sol-gel technique are studied by scanning probe microscopy. It is shown that the surface of the films has quite low roughness of ∼2 nm and small average grain size of 20 nm. It is found that the film is polarized under impact...
We investigated local ferroelectric and piezoelectric properties of nanostructured polymer nanocomposites P(VDF-TrFE)+xBPZT (x = 0-50%) using scanning probe microscopy technique.
In this work, we report on local ferroelectric and piezoelectric properties of nanostructured polymer composites P(VDF-TrFE)+x(Ba,Pb)(Zr,Ti)O3 (x = 0 - 50 %). High-resolution imaging of ferroelectric domains, local polarization switching, and polarization relaxation dynamics were studied by piezoresponse force microscopy. In particular, we found th...
In this paper scanning probe microscopy investigations of surface morphology and local ferroelectric properties of sol-gel deposited PZT thin films are presented. It is shown that the films have sufficiently low surface roughness about 2 nm and small grain size about 20 nm. Possibility of the film polarization by applying both positive and negative...
In terms of development of the methods of producing of the electro-optic lithium niobate thin films on dielectric layers, experiments on the synthesis and studied the domain structure of the films grown on silicon oxide substrate (111) and (100) orientation. The films were synthesized by RF magnetron sputtering, and the primary method of research -...
The spectral dependence of the absorption coefficient in the wavelength range from 190 nm to 1.9 μm of undoped silicon-carbon films synthesized from organosilicon liquid of polyphenylmethylsiloxane (PPMS) by high-frequency deposition from plasma of PPMS vapors is studied. The shortwave absorption region of the films is shown to be nonmonotonic: it...
Piezoresponse force microscopy has been applied for the study of ferroelectric properties of lithium niobate thin films. The films have been obtained on a silicon surface {110}, coated with a thin layer of SiO2 using high-frequency magnetron spraying of lithium niobate. It has been demonstrated that after polarization of a sample surface segment wi...
Lithium niobate crystals with a regular domain structure have been studied by piezoresponse force microscopy. The period of regular domains and the domain-wall width (w = 45 nm) have been calculated for Z- and Y-cut crystals based on an analysis of two-dimensional images of the domain-structure piezoresponse. It is shown that for the Y-cut crystal,...
ABSTRACT ABSTRACT In this work, an Atomic Force Microscope in the so-called Piezoresponse mode and Kelvin mode is used to image the grains, ferroelectric domains and surface potential in lithium niobate thin films. A RF magnetron sputter system was used to deposit LiNbO3 thin films on (100)-oriented Si substrates with SiO2 layer. The surface of the...
La3Ga5SiO14 langasite crystals have been studied before and after 1000–1050 °C, 650 °C vacuum annealing. X-ray photoelectron spectroscopy studies have shown that the relative intensity of the gallium bands in the survey spectra of the annealed langasite crystals at elevated temperatures is one order of magnitude lower compared to the source specime...
This work presents the study of domain structure in uniaxial semiconductor ferroelectrics Sn2P2S6, performed by multi-scale theoretical simulations and piezoresponse force microscopy. We reveal that in spite of the second-order ferroelectric phase transition, domain structure contains metastable paraelectric regions between ferroelectric domains af...
In this work, an Atomic Force Microscope in the so-called Piezoresponse mode and Kelvin mode is used to image the grains, ferroelectric domains and surface potential in lithium niobate thin films. A RF magnetron sputter system was used to deposit LiNbO 3 thin films on (100)-oriented Si substrates with SiO 2 layer. The surface of the sample shows sm...
La3Ga5SiO14 langasite (LGS) crystals have been studied before and after 1000–1050 °C, 650 °C vacuum annealing. XPS studies have shown that the relative intensity of the gallium bands in the survey spectra of the as-annealed LGS crystals at elevated temperatures is one order of magnitude lower compared to the source specimen. To quantify the changes...
The surface of amorphous films with silicon-carbon matrix containing platinum nanoparticles is studied by the methods of scanning probe microscopy. The image obtained by atomic force microscopy shows that the film surface has a random roughness with an average size of less than 1 nm, while the image obtained by scanning tunneling microscopy present...
Original electrothermal method of the manufacturing of the bimorph devices based on single crystals of lithium niobate was proposed. It has been shown that obtained bidomain structures offer several advantages over the traditional bimorph elements based on piezoelectric ceramics. The possible applications of the plates with bidomain structures for...
