The effect of titanium or niobium disulfides doping of iron telluride has been studied for the first time by means of x-ray diffraction analysis, electrical resistivity and magnetization measurements. It has been revealed that an increase in the dopant content in the Fe1.1Te(TS2)(y) (T = Ti, Nb) systems (y = 0, 0.04, 0.08, 0.1, 0.2) is accompanied by the additional phase separation and leads to a decrease in the crystal lattice parameters of the tetragonal phase, partial suppression of antiferromagnetic ordering and an appearance of superconductivity. In doped samples a transition to the superconducting state has been detected upon cooling below T-c(onset) similar to 9 K coexisting with antiferromagnetism. Superconductivity is suggested to exhibit a granular character due to inhomogeneity of the samples and the small volume fraction of superconducting phase. The difference in the superconducting transitions for both dopant types may be associated with different morphologies and compositions of resulting phases.

The [Fe1.1Te +y·NbSe2] composite samples (0 ⩽y⩽ 1.2) have been synthesized for the first time by alloyage of the non-superconducting antiferromagnetic iron telluride and superconducting niobium diselenide. The samples obtained were studied by means of x-ray diffraction, electrical resistivity and magnetization measurements. It has been found that in the range of 0.04 ⩽y⩽ 1.2, superconductivity withTc∼ 12 K coexists with antiferromagnetic order. Despite that in pure 2H-NbSe2the transition temperature does not exceedTc∼ 7.2 K, the critical temperature in composite samples is significantly higher, even in compositions with the dominant NbSe2phase. Atypically rigid superconductivity is observed across the entire NbSe2concentration range, which is attributed to the multiphase and heterogeneous state of the samples, as well as the influence of interface effects at the phase boundaries. Since the observed effect differs significantly from standard substitutions on the chalcogen and/or metallic sublattices, which implies the search for other explanations of the superconducting state, the obtained results seem important for further engineering and design of complex superconducting systems based on bulk samples.

In this work, we have studied the shape evolution of the isolated domains in domain array in congruent lithium niobate crystals under the action of pyroelectric fields arising during multiple irradiation by laser pulses. The loss of the circle shape with the pulse number was obtained in the arrays of isolated domains arising at the edges of the irradiated zone. The simulation of the domain growth under the action of the pyroelectric field allowed revealing two stages of domain shape evolution in the regular domain array. An important role of the neighboring domains was revealed.

In this work we have studied the stripe domain structure created by single pulse IR laser irradiation in CLT crystals covered by a conductive layer. The formation of three types of domain patterns was distinguished: (1) the central region with curved stripe domains, (2) the middle region with straight rays and branches oriented in three directions, and (3) the wide edge region covered by parallel straight rays oriented in only one direction. The obtained results have been considered as domain growth in highly-nonequilibrium switching conditions under the action of spatially nonuniform pyroelectric field arising during cooling after pulse laser irradiation.

Normal anatomy of the left atrial appendage (LAA) of human fetus is of a great importance for fetal cardiac surgery and heart bioprinting. Aim of the study was to clarify the mesoscopic anatomy and histotopography of different parts of the LAA walls in normal human fetuses of 16–22 gestation weeks. Material and methods. We prepared serial histotopograms of the left atrial appendages from 10 normal human fetal hearts stained by Masson trichrome, orcein and fast green. We studied slides by means Olympus CX microscope, TOUPCAM U31S digital camera, and ADF-Image program for measuring. Using a Carl Zeiss EVO LS 10 scanning electron microscope at a magnification of 15–5000 times, three samples were examined using the freeze-chip method. Results. Having measured the outer walls of the LAA intertrabecular spaces, we found that at the level of the middle third of the left atrium, their thickness is minimal in the posterior wall (80 [61–97] μm) (median [lower quartile; upper quartile]), thickness in the anterior wall is 142.9 ± 33.2 μm (mean ± standard deviation) (101 [79–192] μm). At the level of the coronary sulcus, the same parameters were 143.7 ± 23.6 µm (147.5 [90–180] µm) and 137.4 ± 33.9 µm (101 [68–195] µm), respectively. Downward, LAA posterior wall increased about 1.8 in thickness, whereas the thickness of the anterior wall was the same. The endocardium showed the same thickness in all locations. Microanatomically, the LAA myocardium never discovered to build from distinct layers but “anatomical syncytium” or seldom bundles. Collagen and elastic layers were common for endocardium, rare for epicardium. Endocardial elastic fibers interweaved in the underlying collagen so the distinct boundary lacks there. Conclusions. Mesoscopic and microanatomical features of LAA walls in human fetus consist of variable thickness at different levels, unlayered but “syncytial” myocardium, muscleless areas, elastic and collagen layers of the endocardium.

This study explored the changes in wetting property and surface morphology in aluminum alloy plates due to femtosecond laser structuring. The laser scanning produced a hierarchical micro- and nano-scale structure consisting of microchannels decorated by irregular shape particles. The surface morphology was controlled by laser power and scanning line density. The surface wettability gradually changed from hydrophilic to hydrophobic one due to various chemical reactions for low laser power and scanning line density. However, femtosecond laser structuring with appropriate laser power and scanning line density was demonstrated to maintain strong and stable hydrophilic properties of aluminum alloy surfaces.

In this work, the possibility of fabricating composite magneto-optical ceramics by electrophoretic deposition (EPD) of nanopowders and high-temperature vacuum sintering of the compacts was investigated. Holmium oxide was chosen as a magneto-optical material for the study because of its transparency in the mid-IR range. Nanopowders of magneto-optical (Ho0.95La0.05)2O3 (HoLa) material were made by self-propagating high-temperature synthesis. Nanopowders of (Y0.9La0.1)2O3 (YLa) were made by laser synthesis for an inactive matrix. The process of formation of one- and two-layer compacts by EPD of the nanopowders from alcohol suspensions was studied in detail. Acetylacetone was shown to be a good dispersant to obtain alcohol suspensions of the nanopowders, characterized by high zeta potential values (+29–+80 mV), and to carry out a stable EPD process. One-layer compacts were made from the HoLa and YLa nanopowders with a density of 30–43%. It was found out that the introduction of polyvinyl butyral (PVB) into the suspension leads to a decrease in the mass and thickness of the green bodies deposited, but does not significantly affect their density. The possibility of making two-layer (YLa/HoLa) compacts with a thickness of up to 2.6 mm and a density of up to 46% was demonstrated. Sintering such compacts in a vacuum at a temperature of 1750 °C for 10 h leads to the formation of ceramics with a homogeneous boundary between the YLa/HoLa layers and a thickness of the interdiffused ion layer of about 30 μm.

Composites (1 – x )MeWO 4 – x Аl 2 O 3 (Me = Ca, Sr) are synthesized by the solid-phase method. Their phase composition and thermodynamic stability are confirmed by the XRD and TG-DSC data, respectively. Their morphology is studied by the SEM-EDA method. The conductivity of composites is studied by the method of electrochemical impedance spectroscopy as a function of the temperature, the gas-phase oxygen pressure, and the content of added disperse Аl 2 O 3 . It is shown that composites (1 – x )MeWO 4 – x Аl 2 O 3 (Me = Ca, Sr) are ionic conductors and their conductivity is 4–12 times higher as compared with the corresponding tungstates.

The domain growth to the polar surfaces from the tracks created by focused NIR femtosecond pulses in the bulk of MgO-doped lithium niobate plate has been studied. The tracks have been imaged by optical and Cherenkov-type second harmonic generation microscopy. The domain appearance at the irradiated surface has been attributed to domain nucleation and growth under the action of the pyroelectric field arising during cooling after heating by pulse irradiation. The pyroelectric field produced during the sample cooling has stimulated the domain growth to both polar surfaces. The obtained knowledge can be used for development of the domain engineering.

The ordering of a light-induced structure of isolated circular ferroelectric nanodomains was discovered in lithium tantalate crystals under multiple scanning by infrared laser irradiation. The effect was considered as domain arising and growth under the action of alternating in sign pyroelectric field arising during sample heating and subsequent cooling. The circular domains appeared due to 1D to 2D shape transformation after the second scan and grew during subsequent scanning by merging with arising domains accompanied by shape restoration. The ordering of the domain pattern during multiple scanning characterized by an increase in the peak of the autocorrelation function was attributed to domain interaction. This mechanism was confirmed by computer simulation using the kinetic approach based on the analogy between the growth of domains and crystals. It was demonstrated that the quasi-regular pattern of one-size circular domains could be created by scanning with shift. The discovered domain ordering effect is similar to that in magnetic materials.

Composites (1 – x)MeWO4–xАl2O3 (Me = Ca, Sr) are synthesized by the solid-phase method. Their phase composition and thermodynamic stability are confirmed by the XRD and TG-DSC data, respectively. Their morphology is studied by the SEM-EDA method. The conductivity of composites is studied by the method of electrochemical impedance spectroscopy as a function of the temperature, the gas-phase oxygen pressure, and the content of added disperse Аl2O3. It is shown that composites (1 – x)MeWO4–xАl2O3 (Me = Ca, Sr) are ionic conductors and their conductivity is 4–12 times higher as compared with the corresponding tungstates.

The authors previously discovered a new optoplastic effect and observed it under the action of a nanosecond UV laser pulse irradiation of subcritical intensity. In this paper it is shown that under this effect no micropores arise in the subsurface layer of metal. This proves the statement that swelling of metal under laser impact of moderate (subcritical) intensity occurs due to interstitial atoms migrating to the surface and not due to melting with formation of bubbles. At a abrupt cooling (for ~20 μs) interstitial atoms migrate to the surface by the Schottky mechanism due to abnormal mass transfer and the less mobile vacancies have no time to coagulate with formation of micropores in the time of the process.

The iron–tellurium-based compounds Fe 1.1 Te(TiSe 2 ) y doped with titanium diselenide ( y = 0, 0.04, 0.08, 0.1, 0.2) have been synthesized for the first time and studied by means of X-ray diffraction, electrical resistivity and magnetization measurements. It has been shown that the addition of a small amount of titanium diselenide to single-phase iron telluride with a tetragonal crystal structure leads to the appearance of superconductivity, a decrease in the Néel temperature and contraction of the crystal lattice at y ≥ 0.04. The maximal temperature of the onset of the superconducting transition T_c^onset 13 K is observed for a sample with the nominal composition Fe 1.1 Te(TiSe 2 ) 0.1 . The behavior of the resistivity with temperature below T_c^onset is observed to depend on the current value, which may indicate superconductivity characteristic of granular superconductors.

In this work, the possibility of fabrication magneto-optical ceramics by vacuum sintering of compacts prepared by electrophoretic deposition (EPD) from suspensions of (Ho0.95La0.05)2O3 (HoLa) nanopowders made by self-propagating high-temperature synthesis and (Y0.9La0.1)2O3 (YLa) nanopowders made by laser synthesis was systematically investigated. The processes of the formation of bulk one- and two-layer compacts by the EPD method from non-aqueous suspensions of nanopowders was studied. The use of acetylacetone and polyvinyl butyral (PVB) was shown to make it possible to obtain stable alcohol suspensions of the nanopowders characterized by high zeta potential values (+29…+80 mV) and to carry out a stable EPD process. One-layer compacts were made from the YLa and HoLa nanopowders with a density of 30–43%. It was found out that the introduction of PVB into the suspension leads to a decrease in the mass and thickness of the green bodies deposited, but does not significantly affect their density. A possibility to make two-layers (YLa/HoLa) compacts with a thickness of up to 2.6 mm and a density of up to 46% was demonstrated. Sintering such compacts in a vacuum at a temperature of 1750°C for 10 hours leads to the formation of ceramics with a homogeneous boundary between the YLa/HoLa layers and thickness of the interdiffused ions layer of about 30 μm.

—X-ray diffraction, scanning electron microscopy, and magnetic measurements are used to study the structure and magnetic properties of layered ferrimagnetic Fe7S8 and Fe7Se8 compounds depending on the milling time in a ball mill. The milling is shown to lead to the abrupt decrease in the coherent domain size, increase in microstresses, suppression of magnetization anomalies related to low-temperature phase transformations, substantial decrease in the resulting magnetization, and nonmonotonic change in the coercive force. The observed changes in the behavior of magnetization are discussed taking into account the possible redistribution of vacancies in the cation layer in the course of mechanical treatment.

Lithium titanate (Li4Ti5O12) is a commercial anode material used for high-power and long-lifespan lithium batteries. The key drawback of this material is its low electronic conductivity. Although doping is commonly used to solve this problem, the introduction of dopants also diminished lattice stability. In this work, we studied fast and slow laser-induced degradation processes of single Mn-doped lithium titanate particles and proposed a physicochemical model of their degradation mechanism. We suppose that the preferable route of LTO alteration is the formation of amorphous phases rather than crystalline decomposition products. Our results may be useful for not only developing a nondestructive characterization tool utilizing Raman spectroscopy but also for understanding other degradation processes, including thermal alteration and structural changes caused by the intercalation/deintercalation cycles of lithium ions.

The paper presents results of a research on fabrication of magneto-optical ceramics based on Ho2O3 and Dy2O3 sesquioxides. The ceramics were made by hot pressing of powders prepared by self-propagating high-temperature synthesis. The methods and modes of the powder treatment developed made it possible to significantly increase the thickness of the ceramics without deterioration in optical quality in comparison with the samples obtained by vacuum sintering. The characteristics of the ceramics, such as transmission spectrum, thermal conductivity, linear thermal expansion coefficient, microhardness, elastic modulus, and crack resistance have been investigated.

Formation of nanodomain structure after linear scanning by IR laser beam in congruent lithium niobate crystal was attributed to switching under the action of pyroelectric field. The complicated domain patterns consisted of strictly oriented narrow stripe domains (width about 200 nm and depth about 20 mu m) arising in a wide switched band. Width of the switched band and domain length density at different distances from the center of the irradiated zone depend on the scanning velocity v (s). Relevance of the used model was supported by similarity of the experimental and calculated dependences.