Новые публикации

Ferrites are a type of magnetic oxide that have garnered a lot of attention due to their versatile properties and numerous applications in various technological domains. The morphological and structural aspects of ferrites are explained in this chapter, with special attention to the finer points of their crystallography and surface features. The atomic and nanoscale structural configurations that are inherent to matter through analytical techniques such as spectroscopy, electron microscopy, and X-ray diffraction (XRD) are discussed. The first section of the chapter examines the crystallography of ferrites, outlining their different crystal forms and phases, including the ubiquitous spinel structure and hexagonal phases. Extensive investigation of XRD patterns provide insight into lattice properties, crystal symmetry, and phase purity. Techniques including transmission electron microscopy (TEM), atomic force microscopy (AFM), and scanning electron microscopy (SEM) used to examine the surface characteristics, particle size distribution, and agglomeration tendencies are described. We also discuss how the synthesis setting affects the morphological features, which sheds light on the specifics of ferrite creation. In addition to catalysis, the chapter also demonstrates the role of ferrite morphology in a range of applications, including electronics, biomedical, and environmental remediation. The relationship between structural-morphological properties offers insights that could help improve the development and application of ferrite-based materials. The knowledge gained from this chapter should spur advancements in the design, production, and application of ferrite in numerous industries, resulting in advances in electronics, magnetic materials, catalysis, and other domains.

DOI:10.18083/LCAppl.2025.1.52

https://doi.org/10.1364/JOSAA.546862

The scattering problem for anisotropic layered systems is solved by modification of Rumpf’s scattering matrix method [Prog. Electromagn. Res B 35, 241 (2011)
Crossref   ; “Computational electromagnetics. Topic 2” (2024)]. The modified method allows one to calculate the scattering coefficients as well as the electromagnetic field distribution along the layered structure. The method is verified in application to the scattering problem for a cholesteric liquid crystal layer, a magneto-optic structure, a photonic crystal covered by metal, and a slab made of left-handed material.

DOI 10.1088/1361-6668/adc8dd

To study the thermodynamic properties of the disorder-induced transition between �± and �++ superconducting gap functions, we calculate the grand thermodynamic potential Ω in the normal and the superconducting states. An expression for the difference between the two, ΔΩ, is derived for a two-band model for Fe-based systems with nonmagnetic impurities. The disorder is considered in a �-matrix approximation within the multiband Eliashberg theory. In the vicinity of the Born limit near the �±-to-�++ transition, we find two solutions obtained for opposite directions of the system's evolution with respect to the impurity scattering rate. By calculating the change in entropy ΔS and the change in the electronic specific heat ΔC from ΔΩ, we show that such a hysteresis is not due to the time-reversal symmetry breaking state, but that it instead points to the first order phase transition (PT) induced by the nonmagnetic disorder. Based on the ΔΩ calculations, a phase diagram is plotted representing the energetically favorable �± and �++ states and the transition between them. At finite temperature, a first order PT line there is limited by a critical end point. Above that point, the sharp �±→�++ transition transforms into a crossover between �± and �++ states.

https://doi.org/10.1007/s11144-025-02852-w

In this work, spray-dried poly(3-hydroxybutyrate-co-3-hydroxyvalerate) microparticles (P(3HB-co-3HV) MPs) containing conventional antibacterial drug rifampicin (RIF), as well as novel cytostatic ozonide (OZ) were obtained and characterized. The effect of drug chemical structure on its encapsulation and release profile, as well as MPs characteristics (mean size, polydispersity index, zeta potential) was investigated. The obtained RIF-MPs and OZ-MPs revealed the mean diameter of 3.14 ± 0.08 μm and 1.94 ± 0.05 μm, respectively, spherical shape, smooth surface and uniform size distribution. The release of RIF and OZ from the P(3HB-co-3HV) microparticulate matrix had a two-stage pattern with the burst effect and followed the Fickian diffusion-controlled mechanism.

https://doi.org/10.1016/j.materresbull.2025.113485

New noncentrosymmetric molybdate Tm₂Zr(MoO₄)₅ was synthesized. The crystal structure variation with temperature was determined by Rietveld analysis. At 303 K, the monoclinic structure was determined in space group P2₁. A reversible phase transition P2₁↔Cmc2₁ was found at 390 K. From 423 to 520 K, nearly a ZTE (α = 0.7 × 10⁻⁶ K⁻¹) behavior was revealed. In the range of 520–720 K, the negative thermal expansion (NTE) effect (α = -2.3 × 10⁻⁶ K⁻¹) is evident for the cell volume. Tm₂Zr(MoO₄)₅ is stable up to 1100 K. Electronic structures of monoclinic and orthorhombic Tm₂Zr(MoO₄)₅ were evaluated by DFT methods. The bandgap values determined for monoclinic Tm₂Zr(MoO₄)₅ are E_{g direct} = 3.83 eV and E_{g indirect} = 3.43 eV. The vibrational properties of monoclinic phase were characterized by Raman spectroscopy. The photoluminescence emission in monoclinic Tm₂Zr(MoO₄)₅ at 303 K is dominated by a narrower band at 650 nm due to the ¹G₄ - ³F₄ transition.

https://doi.org/10.1016/j.ceramint.2025.04.041

In this study, lanthanum (La) modified 0.85(0.9Na_0.5Bi_0.5TiO₃–0.1Na_0.8Sr_0.1NbO₃) −0.15Sr_0.85Er_0.1TiO₃ ceramics, abbreviated as (NBT–NSN)–SET–xLa, ceramics were synthesised. The best 0.020 La ceramic specimens were selected and improved by viscous polymer processing (VPP) to further enhance their energy storage densities. It ultimately reached a high breakdown field strength of 460 kV/cm, at which the recoverable energy density and efficiency of 6.87 J/cm³ and 74.7 % were attained. At present, although many studies on La doping have shown that La elements can effectively refine grains, thereby increasing electrical breakdown strength and ultimately improving energy storage performance. However, there is no clear explanation at the mechanism layer. In this article we try to make this clearer in terms of structural evolution and modelling. We use XRD and Raman spectroscopy to elucidate the effect of La doping on structural evolution and explain the relationship between structure and properties. In addition, this study combined with comsol software to simulate the electrical breakdown process after La doping, which can help readers to fully understand the mechanism and lay a theoretical foundation for future industrial applications.

https://doi.org/10.1080/1536383X.2025.2485241

Our present study aims to obtain and examine the fullerenols (water-soluble derivatives of fullerenes) with various amounts of hydroxyl groups. The work presents the results of obtaining fullerenols by boiling in nitric acid with subsequent hydrolysis of polynitro intermediates with water at different treatment durations. The obtained samples were certified by X-ray photoelectron and IR spectroscopy methods and it was found that 10-h treatment allowed obtaining fullerenol with the composition C₆₀O_x(OH)_y, where x + y = 12−14, 15-h treatment yielded C₆₀O_x(OH)_y, where x + y = 16−18, and 20-h boiling in acid yielded C₆₀O_x(OH)_y, where x + y = 24−26. The reproducibility of the obtained results allowed the addition of a predictable number of functional groups.

https://doi.org/10.48550/arXiv.2502.01483

The dependence of the energies and orbital structure of local states in the CuO monolayer on intra- and interatomic Coulomb interactions on copper and oxygen orbitals is studied. The electronic system is described within the eight-band p-d model in the hole representation with the on-site energies and hopping integrals obtained using density functional theory. CuO cluster multiparticle eigenstates are calculated using exact diagonalization. The difference between the energy dependencies on the Coulomb parameters for the states with the predominant probability density on the d-orbital and the states in which hole occupies p-orbitals leads to crossover of d- and p-states. The ground single-hole and two-hole states which determine the electronic structure of the low-energy excitations have the character of d- or p-orbitals in the different regions of the Coulomb parameters space. The gap between the energies of the dispersionless quasiparticles forming the top of the valence band and conductivity band also have different values in these two regions. The magnitude of this gap and the orbital character of the local multiparticle states change sharply even with an insignificant change in the Coulomb interactions within the boundary region of parameters between the regions in which the local states are formed by the d- or p-orbitals.

DOI:   https://doi.org/10.1039/D5QI00215J

Broadband near-infrared (NIR) phosphor-converted light-emitting diodes (pc-LEDs) are considered to be at the forefront of the development of next-generation NIR light sources. However, the performance of NIR pc-LEDs is severely limited due to the narrow band emission, low quantum efficiency, and thermal quenching of NIR-emitting materials. Herein, an efficient and thermally stable broadband NIR LaMgGa₁₁O₁₉:Cr³⁺,Yb³⁺ (LMG:Cr³⁺,Yb³⁺) phosphor has been successfully designed by [Cr³⁺–Yb³⁺] co-doping. The broadband emission phenomenon of LaMgGa₁₁O₁₉:Cr³⁺ was confirmed to be due to selective lattice occupancy of Cr³⁺ ions based on the analysis of crystal structures, crystal field calculations, and fluorescence lifetimes. The NIR emission spectra in the range of 1000–1200 nm were enriched by using the highly efficient energy transfer of Cr³⁺ → Yb³⁺ ions and the energy transfer mechanism is discussed in detail. The prepared LMG:Cr³⁺,Yb³⁺ phosphors exhibit highly efficient ultra-broadband NIR emission from 650 to 1200 nm under 440 nm excitation with high internal and external quantum efficiencies of 94.2%/40.5% and excellent luminescence thermal stability of 89.3%@373 K. A NIR pc-LED prototype was fabricated by combining the optimized phosphor with a commercial 440 nm blue LED chip, providing 84.5 mW NIR output power at a 350 mA driving current. Finally, the potential applications of the phosphor in night vision lighting and non-destructive testing were demonstrated. The results show that this work is expected to provide a new strategy for efficient ultra-broadband NIR phosphor design.

https://doi.org/10.1134/S0021364024604706

A one-dimensional photonic crystal with a variable period has been fabricated from porous anodic alumina. A stepwise increase in the period has ensured the broadening of the photonic bandgap from 50 to 170 nm. It has been shown that the introduction of water, alcohol, or acetone into the pores of the crystal allows one to modify the transmission spectrum and to split the passband. It is shown that the combination of angular incidence of light with pore filling makes it possible to use the fabricated crystal as a broad- and narrowband reusable filter.

https://doi.org/10.1134/S2635167624602225

We have shown a novel method for the synthesis of iron silicide nanoparticles on a water-soluble NaCl substrate using thermal layer-by-layer deposition of Fe–Si and post-annealing in ultra-high vacuum. The crystal structure, morphology and optical properties of highly dispersed Fe–Si-containing thin films have been studied. As a result, Fe₃Si nanoparticles were found to spontaneously form on the surface of salt with an excess of iron in a wide stoichiometric range. We propose a simple method to control the geometric shape of synthesized Fe–Si ferromagnetic nanoparticles by preparation of NaCl surface.

https://doi.org/10.1016/j.ceramint.2025.03.189

Antiferroelectric (AFE) ceramic materials, especially those based on lead zirconate (PZ) materials, are renowned for their outstanding energy storage properties, which stem from their unique field-induced phase transitions. These features make them excellent candidates for high-power pulse capacitor applications. However, PZ-based antiferroelectric materials currently suffer significant challenges, including low energy storage density and the inability to simultaneously enhance energy storage efficiency, which greatly impedes their practical application. To address these challenges, this study optimizes both the phase transition and electric breakdown fields, ultimately developing a relaxation antiferroelectric system that facilitates the collaborative improvement of energy storage characteristics. Specifically, Sr²⁺ doped Pb_0.98La_0.02[(Zr_0.5Sn_0.5)_0.88Ti_0.12]_0.995O₃ ceramics were fabricated using the conventional solid-state reaction. The incorporation of Sr²⁺ effectively disrupts the antiparallel polar order of the antiferroelectric phase, thereby stabilizing it. It reduces the potential barrier for phase transition switching and improves the breakdown electric field, thus simultaneously enhancing recoverable energy density and efficiency. The efficiency peaked at 90 % when x = 0.06. Building on this, a viscous polymer processing was used to prepare the ceramic at x = 0.06, showing a recoverable energy density of 6.5 J/cm³ and an energy efficiency of 84 % at 450 kV/cm. Additionally, the ceramic shows remarkable stability within 30–150 °C range, with an efficiency variation of 5.9 %. Furthermore, it performs well in actual discharge energy density (3.22 J/cm³) and power density (131 MW/cm³) at 240 kV/cm.

https://doi.org/10.1016/j.optmat.2025.116924

The orientational structure and spectral properties of a cholesteric layer with planar–conical boundary conditions are studied. Initially, a structure with circular-shaped domains characterized by double twisting of the surface linear defect is formed. Under the influence of an electric field, the domains take the shape of polygons. This system has an asymmetric selective reflection of light: the reflection of right-circularly polarized light close to 100% is observed at a normal incidence of radiation on the sample from the planar boundary conditions, while a selective reflection of light does not occur for radiation incident from the conical anchoring. The light transmission of the sample in the forward direction does not depend on which substrate the radiation falls on. This spectral behaviour is due to the peculiarity of the formation of the domain structure in the cholesteric layer, in which the circular domains are initially located only near the substrate with a conical anchoring. A practically uniform planar cholesteric structure is formed near another substrate with planar boundary conditions. The selective reflection asymmetry is reduced by an applied voltage in the range of 0 to 12 V. The cholesteric transforms into a scattering state at an applied voltage of 12 V <�<72 V and becomes a transparent at �>72 V. Switching off the electric field, under the influence of which the cholesteric is in a transparent state, leads to the restoration of the asymmetry of selective light reflection.

DOI: 10.1109/TDEI.2025.3548971

Using vacuum-arc synthesis, Ultra-high molecular weight polyethylene (UHMWPE)/nano CuO composite samples with a CuO nanoparticle content of 0 to 3 wt.% were obtained. It was found that with an increase in the concentration of nanoparticles, their agglomeration is possible. In addition, with an increase in the concentration of CuO nanoparticles, and accordingly an increase in the time of the polymer modification process, some of the non-polar groups > CH2 are converted into polar groups > C=O, which are easily embedded in the UHMWPE crystal lattice. The electrical properties of pure UHMWPE and UHMWPE/CuO composites were studied by impedance spectroscopy in the frequency range from 10² to 10⁸ Hz and temperatures from 300 K to 420 K. It was found that the dielectric properties of the composite with a CuO nanoparticle content of up to 1 wt.% do not undergo any special changes. The permittivity does not depend on frequency, while the dielectric losses are associated only with through conductivity. With increasing temperature, due to thermal expansion of the polymer and a decrease in its density, the permittivity decreases. With an increase in the nanoparticle content from 2 to 3 wt.% at a frequency of 10⁶ Hz, dielectric relaxation in UHMWPE/nano CuO associated with the formation of polar groups is observed. With increasing temperature, dipole polarization is activated. As a result, dielectric losses increase.

https://doi.org/10.1002/andp.202400319

Fresnel diffraction on double fork-shaped gratings is studied. The trajectories of singularities are found to form two groups of nested spirals, with one originating from each dislocation. The number of spirals nested in each group is found to be equal to the topological charge of the dislocation from which it originates. The influence of the initial distance between dislocations on the trajectories of singularities is examined in detail, and the distinctive characteristics of this dependence are highlighted. The trajectory of the displacement of centroids of singularities from one group of nested spirals during the propagation for various topological charges is investigated. The results demonstrate that the higher the topological of the second dislocation is, the faster the centroid from the first dislocation will shift along the � axis during the propagation. This finding indicates that the trajectory of singularities displacement is not defined by the singularity itself, but rather by the background field, which correlates well with the hydrodynamic approach.

https://doi.org/10.1134/S0021364024603841

The thermodynamic stability and the magnetic and electronic properties of a new two-dimensional magnetic compound (Cr_1 − xFe_x)₃C₂ belonging to the MXen family have been analyzed using ab initio calculations and the cluster approximation. The most stable structure and magnetic configuration of (Cr_1 − xFe_x)₃C₂ have been proposed taking into account the functionalization of the surface with fluorine and oxygen. For the first time, a stable and promising ferrimagnetic MXene (Cr_1/3Fe_2/3)₃C₂ with a high magnetic moment per cell has been discovered, both in the pure form and with the fluorine-functionalized surface.

https://doi.org/10.1134/S0021364024604998

SmFe_{3 – x}Al_x(BO₃)₄ multiferroic single crystals with x = 0–0.28 have been studied in the temperature range T = 3.8−298 K using ⁵⁷Fe Mössbauer spectroscopy and X-ray diffraction analysis. An increase in the Mössbauer hyperfine quadrupole splitting with the content of aluminum x impurities has been found. For all studied samples, the Mössbauer Debye temperatures Θ_M of iron ions have been determined in good agreement with the values for iron ions calculated from X-ray diffraction data. It has been shown that the low-temperature Mössbauer spectral lines of single crystals doped with Al in a magnetically ordered state are broadened compared to the corresponding lines of the undoped SmFe₃(BO₃)₄ ferroborate; this broadening is best approximated within the multilevel spin relaxation model. The Néel temperatures T_N of the magnetic phase transition have been determined for all studied SmFe_{3 – x}Al_x(BO₃)₄ samples. It has been (found that the Néel temperature T_N decreases nonlinearly with an increase in the content x of aluminum, and the type of three-dimensional magnetic ordering changes from planar to Ising.

DOI: 10.1021/jacs.4c16602

https://pubmed.ncbi.nlm.nih.gov/40033799/

Aqueous colloids with a high concentration of nanoparticles and free of steric stabilizers are prospective soft materials, the engineering of which is still challenging. Herein, we prepared superparamagnetic colloids with very large, up to 1350 g/L concentration of 11 nm nanoparticles via Fe²⁺ and Fe³⁺ coprecipitation, water washing, purification using cation-exchange resin, and stabilization with a monolayer of citrate anions (ζ potential of diluted dispersions about -35 mV). XRD, XPS, Mössbauer, and FTIR spectra elucidated the defective reverse spinel structure of magnetite/maghemite (Fe₃O₄/γ-Fe₂O₃) with a reduced content of Fe²⁺ cations. The viscosity increases with nanoparticle concentration and depends also on the nature of citrate salt, being one order of magnitude lower for lithium than sodium and potassium as counter-cation. SAXS/USAXS curves show power-law behavior in the scattering vector range between 0.1 and 0.002 nm^-1, suggesting that particles interact forming fractal clusters, which are looser for Na⁺- and denser for Li⁺-citrate stabilizers (fractal dimensions of 1.9 and 2.4, respectively). In parallel, ATR-FTIR found increasing proportions of symmetric O-H stretching vibrations of ice-like interfacial water in the concentrated colloids. We hypothesize that the clusters arise due to the attraction of like-charge particles possibly involving the water shells and hydration of counter-cations; overlapping the clusters and transition to continuous non-Newtonian phases is seen at viscosity vs concentration plots at 700-900 g/L. The results shed new light on the structure of very concentrated nanocolloids and pave the way for their manufacturing and tailoring.

DOIhttps://doi.org/10.1039/D5TC00206K

Near-infrared phosphor-converted light-emitting diodes (NIR pc-LEDs) have been widely used in plant cultivation. However, exploring NIR phosphors with specific wavelengths and high efficiency is still the main task. In this paper, a NIR phosphor, Lu₃Ga_5−2xMg_xGe_xO₁₂ (LGMG):0.05Cr³⁺, with an emission center wavelength of 726 nm was investigated. After employing the co-substitution strategy, it was found that the strength of the crystal field in the vicinity of Cr³⁺ gradually weakened, resulting in broadening of the emission spectrum to the full width at half maximum (FWHM) of 155 nm. Notably, the developed phosphors have high IQE values and relatively better thermal stability. After optimization, the absorption spectrum of the obtained broadband near-infrared luminescent phosphor showed a high degree of matching with the absorption spectrum of the phytochrome P_FR. NIR pc-LEDs devices were successfully prepared by combining the LGMG:Cr³⁺ phosphor with commercialized blue LED chips. This phosphor has potential applications in plant lighting to promote plant growth.

DOI: 10.1109/ICCT62929.2024.10875001

a silver irregular micromesh transparent conductors with excellent combination of optoelectric characteristics have been obtained in this work. Broadband measurements of EMI shielding properties irregular mesh transparent conductor have been carried out. It is shown that in the high-frequency region the shielding ability reaches saturation and becomes indistinguishable for 600 nm and 1000 nm thick silver mesh transparent conductors. As expected, the key factor for mesh transparent conductor coatings is the average cell size, which turns out to be the limiting factor for shielding at high frequencies. The experimental data are in agreement with the Kantorovich model.

https://doi.org/10.1134/S0031918X24601975

The effect of the Mn_xGe_y buffer layer on the morphology, transport and magnetic properties of Mn₅Ge₃ thin films grown on substrates Si(111) has been studied. Using X-ray diffraction analysis and atomic force microscopy, it has been found that changing the thickness and structure of the buffer layer with a gradient Mn_xGe_y composition has made it possible to control the crystalline quality and smoothness of epitaxial films. Changes in the microstructure and surface roughness has not affected the temperature of the phase transitions revealed from the temperature dependences of the resistivity and magnetization at 75 and 300 K. It has been shown that the features of the magnetization curve shape for films with different buffer layers have been closely related to the inhomogeneity of the films in thickness and surface roughness while maintaining the micromagnetic constants and orientation of the easy magnetization axis. The value of the change in the magnetic part of entropy ΔS has been calculated to be 2.1 J kg^–1 K^–1 at 1 T, which is comparable with the value for gadolinium and exceeds that for Mn₅Ge₃(001) films grown on GaAs substrates.

 https://doi.org/10.1002/jrs.6784

Nickel-cobalt oxyborates (Ni,Co)₃B₂O₆ with a kotoite-type orthorhombic structure are known as antiferromagnetic materials and are of interest for optical applications and as promising battery anode materials. We report and analyze the results of experimental low temperature Raman studies of the phonon spectra measured in some polarizations of the Ni₃B₂O₆, Ni_2.81Co_0.19B₂O₆, Ni_2.4Co_0.6B₂O₆, Ni_2.07Co_0.93B₂O₆, and Co₃B₂O₆ crystals. Simulations of the density functional theory of Raman spectra of the Ni₃B₂O₆ and Co₃B₂O₆ crystals have been performed and analyzed. The vibrational modes of the Ni₃B₂O₆ and Co₃B₂O₆ crystals were interpreted. Low-wavenumber modes in the Raman spectra are associated with Ni and Co atoms vibrations accompanying BO₃ group deformations. Clear evidence of spin-phonon interaction was found for some specific phonons below ��. The anomalies in the behavior of these phonon modes as a function of the nickel concentration in the crystal have been presented. The position and intensity of the Raman modes decrease when the Ni atoms are replaced by Co atoms.

 https://doi.org/10.1002/andp.202400436

Diffraction of shifted incident beam on double fork-shaped gratings with unit charges has been numerically simulated by the using of the Fresnel diffraction integral. The trajectories of singularities dependance on the position of the incident Gaussian beam have been investigated. For the case of same topological charges of dislocations it is shown that the shift of incident beam along the horizontal axis leads to the shift of singularities trajectories along the vertical axis, and vice versa. It is shown, that these results can be qualitatively predicted by using the hydrodynamic approach. For the case of diffraction on double fork-shaped grating which have dislocations with topological charges of opposite signs, the effect of the incident beam center shift depends on the initial distance between dislocations 2⁢�� as well as the initial positions of positive and negative topological charges. The aforementioned findings shows that the result of diffraction on the double fork-shaped gratings highly depends on the position of the incident beam center, and therefore, it provides the valuable information that can enrich our understanding of the spatial dynamics of optical vortices.

https://doi.org/10.1016/j.jeurceramsoc.2025.117319

Samarium monosulfide (SmS) is a unique tensometric material. For the first time, SmS ceramics for magnetron sputtering films were synthesized. A powder of up to 100 mol% SmS was produced via the reaction of γ-Sm₂S_2.98 with excess metallic samarium vapor. The conditions for target and side reactions were determined. SmS ceramic targets were fabricated by pressing under standard conditions and annealed at high temperatures. Ceramic properties—density, hardness, and compressive strength—improved with increasing pressing pressure. Conditions for stable magnetron discharge over the SmS target were established. The composition of films deposited on silicon substrates varies with the substrate-to-target angle, transitioning from SmS_1.9 to SmS. During magnetron discharge, SmS dissociates into samarium and sulfur, with their distribution approximated by angular equations. High-mass Sm and SmS particles distribute radially, while sulfur concentration forms an ellipse elongated toward low angles. The deposition angle range for SmS was determined.

https://doi.org/10.1134/S1062873824709036

The relative influence of two different crystal structures of the composite compound Bi₂(Sn_0.7Fe_0.3)₂O₇/Bi₂Fe₄O₉ with a ratio of 91/9% studied using Raman scattering method. The Raman spectra were studied in the temperature range 93–520 K and the frequency range 1–2000 cm^–1. The types of lattice vibrations are determined. A decrease of the frequency of Raman spectra modes was found in the regions of phase transitions Bi₂(Sn_0.7Fe_0.3)₂O₇ and Bi₂Fe₄O₉. A new mode 406 cm^–1 has been established, which is a mixed oscillation of SnO₆ in Bi₂(Sn_0.7Fe_0.3)₂O₇ polyhedra (F_2g) at a frequency 400 cm^–1 and stretching vibrations of the FeO₆ octahedral at a frequency 426 cm^–1 Bi₂Fe₄O₉.

https://doi.org/10.1134/S1062873824709371

In the period from winter to spring 2024, a series of measurements of interference reflectograms from layered structures of ice surfaces of freshwater and salt reservoirs of the Krasnoyarsk Territory and the Republic of Khakassia were carried out. These measurements were performed using signals from navigation satellites operating in the L1 band. The experimental data obtained in the form of amplitude-time dependencies were processed using the fast Fourier transform algorithm. Subsequent analysis of the measurement processing results allowed us to conclude that the GNSS reflectometry method is highly sensitive to determining the macrophysical characteristics of ice surfaces with different salinity of reservoirs.

https://doi.org/10.1134/S1062873824709000

We investigated the optoelectric characteristics of transparent conducting structures of oxide/metal/oxide (OMO) type, where In₂O₃ is used as an oxide and Ag is used as a metal. Samples were obtained by magnetron sputtering. The focus is on the influence of the thickness and homogeneity of the silver layer on the optical and electrical properties of the structures. We use an ion etching method to improve performance of silver thin films and reduce thickness. Usually, in the case of poor wetting of the metal oxide substrate, the thin film grows by the island mechanism (Volmer–Weber mechanism), which leads to poor properties of the OMO structures. The proposed method consists of “thinning” the obvious continuous silver films using ion etching, because of which the thin silver films become closer to the films growing by the layer-by-layer mechanism (Frank–van der Merwe mechanism). The results obtained showed that ion etching allows us to achieve higher transparency of the structure without crucial loosing of electrical conductivity. This makes the method promising for further application in optoelectronic devices such as solar cells and displays.

 https://doi.org/10.1002/adfm.202500806

Exploring new types of scintillators, especially fabricating large-area scintillating screens, is essential in applications of life science, industry, and material science. However, the thickness and light scattering in composite scintillator film present a major challenge for balancing the spatial resolution and radioluminescence intensity. Herein, an in situ crystallization route is developed to innovate the preparation of the large-area scintillating screens based on the hybrid copper(I)-based C₆H₈N₂OCuX (X = I and Br), in which carboxymethylcellulose sodium (CMC-Na) contribute to the “CMC-Na membrane” film formation and further increase absorption cross-section for X-ray radiation owing to the existence of Na elements. The choice of halogen can regulate the photoluminescence of C₆H₈N₂OCuX (X = I, Br, and Cl) from cyan to green and then to yellow, and significant scintillation property can be achieved for C₆H₈N₂OCuI with the light yield of 52 000 photons MeV⁻¹ and detection limit of 43.14 nGy s⁻¹. Finally, the high X-ray absorption assisted by CMC-Na, as well as the thin thickness of the composite scintillator films help to realize remarkable spatial resolution above 14 lp mm⁻¹. This study provides a foundation for discovering high-performance copper(I)-based halides scintillators and offers a creative think film preparation method for X-ray imaging.

https://doi.org/10.3390/inorganics13020034

This study explores the phase composition, local atomic structure, and magnetic properties of biogenic nanomaterials synthesized through microbially mediated biomineralization by the sulfate-reducing bacterium Desulfovibrio species strain A2 (Cupidesulfovibrio). Using X-ray diffraction (XRD), transmission electron microscopy (TEM), Mössbauer spectroscopy, X-ray absorption near-edge structure (XANES) spectroscopy, extended X-ray absorption fine structure (EXAFS) spectroscopy, and magnetic measurements, we identified a mixture of vivianite (Fe₃(PO₄)₂·8H₂O) and sulfur-containing crystalline phases (α-sulfur). XRD analysis confirmed that the vivianite phase, with a monoclinic I2/m structure, constitutes 44% of the sample, while sulfur-containing phases (α-sulfur, Fddd) account for 56%, likely as a result of bacterial sulfate-reducing activity. X-ray absorption spectroscopy (XAS) and EXAFS revealed the presence of multiple sulfur oxidation states, including elemental sulfur and sulfate (S⁶⁺), underscoring the role of sulfur in the sample’s structure. Mössbauer spectroscopy identified the presence of ferrihydrite nanoparticles with a blocking temperature of approximately 45 K. Magnetic measurements revealed significant coercivity (~2 kOe) at 4.2 K, attributed to the blocked ferrihydrite nanoparticles. The results provide new insights into the structural and magnetic properties of these microbially mediated biogenic nanomaterials, highlighting their potential applications in magnetic-based technologies.