New Publications

 https://doi.org/10.3390/magnetochemistry11090072

High-calcium fly ash (HCFA), produced from the lignite combustion, has emerged as a global concern due to its fine particle size and adverse environmental impacts. This study presents the characteristics of dispersed microspheres from HCFA obtained using modern techniques, such as XRD, SEM-EDS, ⁵⁷Fe Mössbauer spectroscopy, DSC-TG, particle size analysis, and magnetic measurements. It is found that an increase in microsphere size is likely due to the growth of the silicate glass-like phase, while the magnetic crystalline phase content remains stable. According to the ⁵⁷Fe Mössbauer spectroscopy, there are two substituted Ca-based ferrites—CaFe₂O₄ and Ca₂Fe₂O₅ with a quite different magnetic behavior. Besides, the magnetic ordering temperature of the brownmillerite (Ca₂Fe₂O₅) phase increases with the average diameter of the microspheres. FORC analysis reveals enhanced magnetic interactions as microsphere size increases, indicating an elevation in the concentration of magnetic microparticles, primarily on the microsphere surface, as supported by electron microscopy data. The discovered the magnetic crystallographic phases distribution on the microsphere’s surface claims the accessibility for further enrichment of the magnetically active particles and the possible application of fly ashes as a cheap source for magnetic materials synthesis.

https://doi.org/10.1063/5.0235000

Rare earth substitution in cuprate superconductors has sparked intense interest, driving progress in both fundamental research and advanced technology. In this investigation, we focus on SmBa 2Cu 3O 7−� (SmBCO), synthesized via the top-seeded melt growth method, with an aim to understand the corresponding vortex phases. Despite the minimal impact on transition temperature (⁠ ��⁠) when yttrium in YBa 2Cu 3O 7−� is replaced by Sm, the critical current density (⁠ ��⁠) remains exceptionally high under intense magnetic fields. Introducing Sm 2Ba 1Cu 1O 5 (Sm-211) phase as point defects significantly boosts the pinning potential (⁠ �⁠) and pinning force (⁠ ��⁠) and enhances their stability against external magnetic fields. Contrary to other superconductors, the SmBCO sample displays a notable peak effect in the magnetic field-dependent ��⁠, driven by point defects introduced by the Sm-211 phase, which prompts vortex lattice softening and initiates a transition from an ordered to a disordered vortex glass phase, leading to the emergence of a second magnetization peak. Analysis suggests that the primary pinning mechanism in SmBCO involves a combination of normal point and Δ� pinning. Additionally, investigations of the vortex glass phase beneath the thermally activated flux flow regime indicate that vortices in SmBCO may freeze into a state akin to a 2D vortex glass state. This study leads to a detailed phase diagram that clarifies the evolution of vortex phases in SmBCO.

https://doi.org/10.1021/acs.chemmater.5c01429

Introducing large-radius cations usually causes structural relaxation, leading to a spectral redshift and low optical performance in Cr³⁺-activated phosphors. Here, MNAl₁₀O₁₇:Cr³⁺ phosphors are synthesized, and the substitution of large-radius cations induces the abnormal lattice shrinkage of the N site and atomic site splitting of the M site due to the unique hexaaluminate structure, further distinctly improving luminescent properties. To investigate the university of atomic site splitting, a series of phosphors, Na_2(1–m)K_2mAl_10.8O₁₇:0.2Cr³⁺ and Gd_1–nLa_nMgAl_10.8O₁₉:0.2Cr³⁺, are synthesized, and the variation of their luminescent properties conforms to the expected rule. Finally, Ga³⁺ ions are introduced to improve the luminescence efficiency. Internal/external quantum efficiencies of the optimal sample are 98.1 and 65.8%, respectively. Meanwhile, an anomalous spectral blueshift indicates the existence of Cr³⁺–Cr³⁺ exchange coupling pairs, and a comparative analysis of similar cases is conducted to provide some insights into the luminescence of coupling pairs.

https://doi.org/10.1016/j.jallcom.2025.183960

Cr³⁺-doped phosphors still suffer from limitations, such as low quantum efficiency, poor thermal stability, and spectral peak mismatch, restricting their application in pc-LEDs for indoor agriculture. In this study, cation Sc substitution strategy was applied in Y₃Ga₅O₁₂. Given that the emission location, an efficient far-red (FR) phosphor Y₃ScGa₄O₁₂:Cr³⁺ (YSGO:Cr³⁺) with high matching to phytochrome was constructed, under 442 nm excitation, realizing FR emission (728 nm) with FWHM 99 nm. The optimized phosphor demonstrates exceptionally high internal quantum efficiency of 95.4 % and excellent thermal quenching property (91.6 %@423 K). Furthermore, a fabricated phosphor-converted light-emitting diode (pc-LED), combining YSGO:0.07 Cr³⁺ with a 450 nm chip, delivers FR output power of 36.74 mW with a photoelectric conversion efficiency (PCE) of 12.8 % at 100 mA, demonstrating ultra-low quenching rate (<5 % intensity loss after 3 months operation). A supplemental lighting model for lettuce growth was constructed, which significantly improves in physiological parameters, confirming the great potential of this phosphor for plant lighting applications.

DOI: https://doi.org/10.1103/gymx-jk1g

Magnon-phonon hybridization in ordered materials is a crucial phenomenon with significant implications for spintronics, magnonics, and quantum materials research. We present direct experimental evidence and theoretical insights into magnon-phonon coupling in Mn3⁢Ge, a kagome antiferromagnet with noncollinear spin order. Using inelastic x-ray scattering and ab initio modeling, we uncover strong hybridization between planar spin fluctuations and transverse optical phonons, resulting in a large hybridization gap of  ∼2  meV. This coupling is driven by interlayer Heisenberg exchange interactions and is enhanced by the material’s symmetry and magnetic frustration. The simplicity of the Mn3⁢Ge structure enables clear identification of the hybridized modes, bridging theoretical predictions and experimental observations. Our findings establish Mn3⁢Ge as a model system for exploring magnon-phonon interactions and offer a pathway for designing materials with tunable magnetoelastic properties.

https://doi.org/10.3390/ma18174102

Highly efficient shielding materials, transparent in the visible and IR ranges are becoming important in practice. This stimulates the development of cheap methods for creating transparent conductors with low sheet resistance and high optical transparency. This work presents a complex approach based on preliminary modeling of the shielding characteristics of two-layer sandwich structures based on irregular aluminum mesh (IAM) formed by the cracked template method. Experimentally measured spectral dependences of the transmission coefficient of single-layer IAM are used as a reference point for modeling. According to the simulation results, two types of sandwich structures were designed using IAM, with varying filling factors and a fixed PMMA layer thickness of 4 mm. The experimentally measured shielding characteristics of the sandwich structures in the range of 0.01–7 GHz are in good agreement with the calculated data. The obtained structures demonstrate a shielding efficiency of 55.96 dB and 65.55 dB at a frequency of 3.5 GHz (the average range of 5G communications). At the same time, their optical transparency at a wavelength of 550 nm are 84.07% and 75.78%, respectively. Our sandwich structures show electromagnetic shielding performance and uniform diffraction pattern. It gives them an advantage over structures based on regular meshes. The obtained results highlight the prospect of the proposed comprehensive approach for obtaining highly efficient, low-cost optically transparent shielding structures. Such materials are needed for modern wireless communication systems and metrology applications.

https://doi.org/10.3390/molecules30173604

Rapeseed is a valuable oilseed crop, and efficient drying plays a crucial role in preserving its quality. Because of the high moisture content in rapeseed, drying using the conventional methods may cause it to overheat. The benefit of energy-efficient sorption drying is that it allows one to carefully remove moisture from seeds without using heat, thus ensuring better quality. This study focuses on the characteristics of rapeseed drying using fine crystalline magnesium sulfate MgSO₄·nH₂O as a desiccant. The properties of the desiccant were analyzed using the SEM–EDS, XRD, ATR–MIR, and DSC-TG techniques before and after contacting rapeseed. The findings demonstrate that the desired moisture content of 7–8% can be achieved within 60–240 min, depending on the initial moisture content of rapeseed (ranging from 12% to 16%) and the desiccant-to-rapeseed ratio (1:2, 1:4, or 1:6). An analysis of crystalline hydrates after sorption drying indicates that the desiccant can be reused without intermediate regeneration during multi-stage drying of two to three rapeseed batches. The germination capacity of the seeds after sorption drying was as high as 90%, meeting the standards for elite rapeseed categories. This research demonstrates that sorption drying using magnesium sulfate is an efficient method for reducing moisture content in oilseeds, while maintaining their quality.

DOI: 10.1039/d5dt01230a

A novel oxyborate, NiCr(BO₃)O, is synthesized using a flux method. The material crystallizes in an orthorhombic warwickite structure, space group Pbnm(62), with lattice parameters a = 9.3438(13) Å, b = 9.0908(13) Å, and c = 3.0507(4) Å. Although Ni and Cr atoms are highly disordered over two inequivalent metal sites, the compound undergoes a magnetic phase transition at T_N = 45 K, as characterized by maximum dc magnetization and ac susceptibility and a λ-peak in heat capacity. Upon further cooling, another magnetic anomaly occurs at about 10 K. At high temperatures, magnetic susceptibility follows the Curie-Weiss law, with a highly negative Weiss temperature (θ ≈ -130 K), indicating strong predominance of antiferromagnetic coupling. The effective magnetic moment (μ_eff) is ≈4.9μ_B per f.u. Field-induced spin-orientation transition is observed below T_N for an external field applied perpendicular to the c-axis. Magnetic heat capacity was determined by subtracting the lattice heat capacity of the nonmagnetic analog. Debye temperature is evaluated to be 365 K. NiCr(BO₃)O is the first example demonstrating magnetic ordering in the highly disordered oxyborate family.

https://doi.org/10.1016/j.cej.2025.168055

Development of multifunctional nanomaterials for visible-light-driven environmental remediation remains a major challenge in green chemical engineering. In this study, we report on solution combustion synthesis of biocompatible Sc_xLu_1-xFeO₃ (x = 0, 0.5, 1) nanocrystals with unique photocatalytic and magnetic properties. Structural characterization confirmed phase-pure formation of orthorhombic (o-LuFeO₃), hexagonal (h-Sc_0.5Lu_0.5FeO₃), and cubic (c-ScFeO₃) perovskite-type phases with crystallite sizes of 89.3, 36.7, and 54.3 nm, respectively. Morphologically, the materials exhibited a porous foam-like architecture with BET surface areas of 10.06–14.36 m²/g and dominant mesopores (3.9–11.2 nm). Diffuse reflectance spectroscopy revealed a strong visible-light absorption and narrow band gaps ranging from 1.97 to 2.30 eV. Under visible-light irradiation (λ = 410 nm), h-Sc_0.5Lu_0.5FeO₃ showed superior photocatalytic degradation of methylene blue, achieving 100 % removal within 30 min with a rate constant of 0.1448 min⁻¹, outperforming both o-LuFeO₃ (45 %, 0.0206 min⁻¹) and c-ScFeO₃ (60 %, 0.0321 min⁻¹). Magnetic studies revealed strong coercivity in o-LuFeO₃ (2.5 T), spin-glass-like features in h-Sc_0.5Lu_0.5FeO₃ (T_N = 151 K), and weak antiferromagnetism in c-ScFeO₃. Biocompatibility testing using THP-1 and K562 cell lines showed more than 80 % of cell survival at concentrations up to 0.25 mg/mL, with no significant morphological damage among THP-1 and K562 cells. Owing to their combined photocatalytic efficiency, magnetic separability, and biological safety, these materials are promising for integration into hybrid wastewater treatment systems as biocompatible visible-light-responsive photocatalysts.

https://doi.org/10.1016/j.jssc.2025.125637

Y₂OSe₂, a novel phosphor matrix, was first synthesized via sintering/melt crystallization of Y₂Se₃ and Y₂O₂Se precursors. Guided by LLM predictions (accurately forecasting synthesis at 800–1000 °C and incongruent melting ∼1450 °C), it crystallizes orthorhombically (Pnma, Gd₂OSe₂-type; a = 15.9748 (2), b = 3.89420 (5), c = 6.96804 (9) Å, V = 433.476 (10) ų, Z = 4), contrasting the LLM's initial monoclinic (P2₁/c) prediction. Particles are oval with layered granular morphology (microhardness 290 ± 8 HV). The phase is stable under standard conditions and melts incongruently at 1470 ± 8 °C (forming melt + Y₂O₂Se), validating LLM thermal forecasts. Polycrystalline Y₂OSe₂ coexists in equilibrium with Y₂Se₃ or Y₂O₂Se. Raman spectra analysis, combining experimental data and DFT calculations, was performed. It has been shown that in the crystal structure of Y₂OSe₂, ion vibrations exhibit collective behavior in the low-frequency region, while the intense peaks above 110 cm^–1 are mainly due to vibrations of specific types of ions. The simulation of the band structure and of the absorption spectrum reveals the origin of the onset of fundamental absorption, namely, the onset of direct transition at 1.76 eV into highly dispersive part of conduction band that contributes to the indirect bandgap, then the onset of more pronounced absorption above 3 eV at transitions to less dispersive part of conduction band. Four of five experimentally observed bands in the absorption spectrum are present in the simulated spectrum. Observed features are common to a variety of chalcogenides that were investigated in last two years.

https://doi.org/10.1016/j.jssc.2025.125610

Detailed studies of heat capacity, thermal expansion, sensitivity to hydrostatic pressure, as well as mechanocaloric effects were carried out for single-crystal and ceramic (NH₄)₃H(SO₄)₂ undergoing a number of structural transformations at atmospheric pressure: R-3m ↔ (C2/c) ↔ (P2/n)₁ ↔ (P2/n)₂ ↔ P-1. A significant smearing of the anomalous contribution to the deformation of the ceramic sample was observed, especially near first order transformations, while the behavior and values of the anomalous entropy are in satisfactory agreement for both samples. For the first time, the region of the T – p phase diagram, including low temperature phase transitions, was experimentally investigated. A good correspondence was found between the measured and calculated volumetric baric coefficients. A comparative analysis of the baro(BCE)- and piezo(PCE)-caloric effects was carried out using entropy–temperature phase diagrams at various hydrostatic/uniaxial pressures. Inverse BCE is characteristic of all studied phase transitions, which is caused by a decrease in their temperatures under hydrostatic pressure. Due to rather low symmetry of the crystalline phases, (NH₄)₃H(SO₄)₂ demonstrates a strong anisotropy in the thermal expansion which leads in turn to the difference in the values and sign of the linear baric coefficients and, as a result, to conventional and inverse PCE associated with the various crystallographic axes. The caloric parameters of single-crystal and ceramic (NH₄)₃H(SO₄)₂ are analyzed in comparison with some other derivatives of ammonium sulphate.

https://doi.org/10.1016/j.photonics.2025.101436

Bound states in the continuum (BICs) are specific resonant modes with infinite radiative quality factors that arise from a mismatch with free-space radiation through mechanisms of symmetry protection, parameter tuning, or accidental degeneracy. To harness the significant potential of BICs for light-emission applications such as LEDs and lasers, it is essential to efficiently integrate light-emitting nanomaterials with BIC-based architectures. Here, we numerically model the effect of a light-emitting capping layer on the plasmon-photonic hybrid system consisting of an aluminum substrate with a two-dimensional periodic wave-like interface to an anodic alumina photonic crystal slab. We consider CdSe/CdS nanoplatelets (NPLs) as the gain material because of their high potential for industrial applications. The proposed practical guide for compliance with the conditions for bound states formation, spectrally aligned with the photoluminescence band of the NPLs, can be further used for experimental realization in high-performance solution-processable lasers.

https://doi.org/10.1016/j.jallcom.2025.183213

Complex ludwigite Cu2MnBO5 was doped by Cr ions in amount of 0.08 per unit cell. It demonstrates two close phase transition temperatures of 52 and 59 K into a canonical spin-glass state. It is shown that with an increase of the external magnetic field up to the magnetic field 3 T, the effective magnetic moment drops from 5.33 up to 4.38 �B and Curie–Weiss temperature elevates from −70 up to −15 K. This is probably due to the transition from a high-spin state to a low-spin state for manganese ions. The magnetization, XPS and EPR spectra were measured. The temperature dependence of the specific heat in a zero magnetic field and 9T has been measured. It is shown that Einstein temperatures change in a 9T magnetic field.

https://doi.org/10.1038/s41598-025-16192-1

We consider resonances induced by symmetry protected bound states in the continuum in dielectric gratings with in-plane mirror symmetry. It is shown that the shape of the resonance in transmittance is controlled by two parameters in a generic formula which can be derived in the framework of the coupled mode theory. It is numerically demonstrated that the formula encompasses various line-shapes including asymmetric Fano, Lorentzian, and anti-Lorentzian resonances. It is confirmed that the transmittance zeros are always present even in the absence up-down symmetry. At the same time reflectance zeros are not generally present in the single mode approximation. It is found that the line-shapes of Fano resonances can be predicted to a good accuracy by the random forest machine learning method which outperforms the standard least square methods approximation in error by an order of magnitude in error with the training dataset size �≈104.

https://orcid.org/0000-0002-6000-4930

Near-infrared (NIR) light has a high application value in various fields due to its spectral characteristics. Typically, the broadband NIR emission of Cr³⁺ is based on the transition of ⁴T₂→⁴A₂, while the ²E level emits narrowband emission. This work discovered broadband NIR emission from the [⁴A₂, ⁴T₂] coupling excited state energy level in the spinel structure. The dense and adjacent Al1O₆ as the occupied sites of Cr³⁺ provides a structural basis for the exchange coupling effect under high Cr³⁺ concentration, as confirmed by the analysis of site occupancy, formation energy, bond valence sum, and effective coordination number. Spectral information and EPR signals indicate that the [⁴A₂, ⁴T₂] coupling excited state in the emission spectrum corresponds to the downward shift of the T₂ energy level caused by the Cr³⁺–Cr³⁺ exchange coupling interaction in the strong crystal field of LAO:Cr³⁺. The internal and external quantum efficiencies of LAO:0.15Cr³⁺ are 80.6% and 30.3%, respectively. The luminescence intensity at 370 and 423 K is approximately 92% and 85% respectively of that at room temperature. The excellent luminescence thermal stability is attributed to the activation energy of 0.21 eV and the Huang–Rhys factor S = 3.95. Finally, the material was fabricated into pc-LEDs and its applications in night vision and plant lighting were explored.

https://doi.org/10.1016/j.jmmm.2025.173467

This work explores the magnetic phase transition and magnetocaloric properties of epitaxial Mn₅Ge₃ (001) films on Si(111) synthesized via molecular beam epitaxy. Critical exponents (β = 0.34 ± 0.01, γ = 1.05 ± 0.01, δ = 3.82 ± 0.16) exhibit behavior between 3D Ising and Heisenberg models, attributed to anisotropic exchange interactions. Magnetocaloric entropy change (ΔS) and relative cooling power (RCP) were calculated from isothermal magnetization data, yielding ΔS_max = 3.2 ± 0.21 J·kg⁻¹·K⁻¹ and RCP = 91 ± 6 J·kg⁻¹ at 15 kOe, comparable to bulk Mn₅Ge₃. At low field (H < 6 kOe) positive ΔS is observed due to magnetocrystalline anisotropy. At high filed (H = 15 kOe) estimated adiabatic temperature changes (ΔT_ad) is 1.5 ± 0.1 K. The films’ critical indices and magnetocaloric performance align closely with bulk material, demonstrating minimal decrease from interfacial and strain effects. These results highlight Mn₅Ge₃ thin films as possible candidates for rare-earth-free solid-state cooling micro and nanodevices, combining relatively high efficiency and scalable integration into microsystems. The study advances the understanding of thin film magnetocaloric materials for future application in energy-efficient technologies

https://doi.org/10.1134/S0021364025607353

Magnetic hysteresis loops of two representative samples of synthetic ferrihydrite nanoparticles with the same sizes (the average size of ≈2.7 nm) and various interparticle distances have been studied under cooling conditions in the presence and absence of an external field. One initial sample is characterized by the aggregation of nanoparticles, and a shift in the magnetic hysteresis loop along the abscissa axis is observed after cooling from a temperature exceeding the superparamagnetic blocking temperature in the external field. The particles in another sample are spatially separated by coating their surface with an arabinogalactan layer, and the shift of the hysteresis loop after cooling in the external field is not observed in this sample. This experimental fact indicates that one of the important factors determining the shift of the hysteresis loop of nanoparticle systems is a pronounced subsystem of surface spins formed during the close contact of particles, which can be considered as a kind of the surface effect. Because of the exchange coupling between the subsystem of surface spins (common for a conglomerate of particles) and uncompensated moments of particles, an additional source of the unidirectional magnetic anisotropy arises during cooling in the external field, which is the origin of the observed exchange bias of the magnetic hysteresis loop.

https://doi.org/10.1016/j.jallcom.2025.182636

Recently, Cr³⁺-doped fluoride materials for phosphor-converted near-infrared light-emitting diodes (NIR pc-LEDs) have been extensively studied, however, their external quantum efficiency (EQE) must be improved. In addition, designing broadband NIR-emitting fluoride phosphors that are sufficiently excited by blue light to match with commercial 460 nm InGaN LED chips is still challenging. In this work, broadband NIR-emitting Cs₂KGaF₆:Cr³⁺, Mn⁴⁺ (CKGF:Cr, Mn) phosphors are synthesized through ion exchange route. Tunable excitation of CKGF:Cr NIR phosphor shifts from 430 nm to 460 nm by co-doping with Mn⁴⁺, which could serve as an additional strategy to improve the photoluminescence of Cr³⁺-doped broadband NIR-emitting phosphors. The NIR emission of CKGF:Cr, Mn is significantly improved, with internal quantum efficiency (IQE) and EQE of 85.9% and 29.0%, respectively. The Mn-free CKGF:Cr phosphor, in comparison, has an EQE of only 15.8% (�ex �ex = 467 nm) and 20.0% (�ex = 433 nm). Furthermore, with excellent thermal stability, CKGF:Cr, Mn phosphor are well suitable for LED applications and the fabricated NIR pc-LED device has high photoelectric efficiency (19.4%@20 mA) and it well performs in night vision, quick inspection and strengthening for deep colors. The described ion exchange method of Cr³⁺-doped fluoride NIR phosphors by co-doping with Mn⁴⁺ is an attractive strategy for optimizing the luminescent properties of blue-excited NIR phosphors.

https://doi.org/10.1111/jace.70177

Lead-free dielectric ceramics are gaining prominence in energy storage due to their superior power density and rapid charge/discharge capabilities. However, Na_0.5Bi_0.5TiO₃ (NBT)-based ceramics stand out as particularly promising dielectric materials, but face two critical challenges: excessive remnant polarization and inadequate dielectric strength, which substantially limit their energy storage performance. To enhance energy storage performance in lead-free ferroelectric ceramics, a stepwise optimization method was adopted in this study. The strategy combines compositional engineering through precise elemental ratio adjustment to tailor microstructural characteristics, and processing optimization to significantly enhance breakdown strength (E_b). This dual-approach methodology has been experimentally demonstrated to effectively boost the energy storage capabilities of the ceramic system. The incorporation of SrTiO₃ as a modifier successfully induced nanoscale domain structures in the 0.91Na_0.5Bi_0.5TiO₃-0.09K_0.7La_0.1NbO₃ (NBT-KLN-based) system, yielding desirable slim P-E loops. Subsequently, the viscous polymer processing (VPP) technique was utilized to minimize defects and boost density, thereby significantly enhancing the E_b. The optimized NBT-KLN-0.20ST-vpp composite ceramics demonstrated remarkable energy storage properties, achieving a high W_rec of 5.34 J/cm³ and efficiency of 82% under 460 kV/cm. This study not only offers a viable strategy for improving NBT-based ceramics but also lays the groundwork for designing advanced energy storage materials, demonstrating promising applications in compact power electronics.

https://doi.org/10.1134/S0023158425600348

Electrodes based on TiO₂ nanotube arrays for the photoelectrochemical process of water splitting were modified with Cu₂O, a p-type semiconductor (p-Cu₂O). Cyclic voltammetry (CV) was used for the deposition of p-Cu₂O nanoparticles to achieve a more uniform distribution of the particles over the inner and outer surfaces of TiO₂ nanotubes. The measurements of incident photon-to-current conversion efficiency (IPCE) in the range of 365–660 nm demonstrated that the proposed method significantly enhanced photoactivity in the visible light region compared to the potentiostatic deposition method. The IPCE value was 0.18% at a wavelength of 523 nm, which was 7 and 45 times higher than those for the potentiostatically modified and pristine samples, respectively. Under continuous illumination with visible light at a wavelength of 523 nm and a potential of 0.2 V (Ag/AgCl_(sat.)), a transition from Cu₂O to CuO was observed for 5 h, which was accompanied by a decrease in the photocurrent density.

https://doi.org/10.1364/AO.568733

Developing tunable photodetectors that can operate over a wide range of wavelengths and integrating them into integrated circuits is a significant challenge in today’s technology. These devices must be miniaturized, inexpensive, and easily manufactured. To address this challenge, we propose the development of a tunable planar hot-electron photodetector based on Tamm plasmon-polariton. Operational wavelength tuning is achieved by incorporating a material with a phase transition, Sb2S3, into a Tamm plasmon-polariton-based structure. This allows for tuning the detection wavelength over a broad range encompassing all bands of the telecommunications spectrum.

 https://doi.org/10.1002/jrs.70001

This study examines the temperature-dependent Raman spectra of MBE-grown bismuth telluride (Bi₂Te₃) thin films, analyzing Stokes, and anti-Stokes scattering in two polarizations to resolve symmetry-dependent mode strengths. Density functional theory simulations of Stokes spectra identified the fundamental vibrational modes and anharmonic decay. The temperature evolution of phonon wavenumbers and linewidths revealed the role of anharmonicity: the real part of the phonon self-energy governs the wavenumber shift (redshift) of the A1⁢�2 mode, while its imaginary part drives the linewidth broadening, both arising from cubic and quartic anharmonic processes which is associated to energy and symmetry of the mode. In contrast, the lower wavenumber A1⁢�1 and E�2 modes exhibited weaker coupling to thermal decay channels, reflected in smaller changes to their self-energy components and longer lifetimes. The intensity of A1⁢�2 mode decreased significantly with temperature due to multi-phonon decay, whereas A1⁢�1 and E�2 intensities remained stable. These results quantify the distinct mediation of wavenumber renormalization and lifetime effects in Bi₂Te₃ by the real and imaginary components of the phonon self-energy.

https://doi.org/10.22184/1993-7296.FRos.2025.19.4.304.311

Time-dependent density functional theory-based approaches, TD-DFT and TD-DFTB, are used to study the optical absorption of B800 part of light-harvesting complex 2 (LH2) of Rhodoblastus acidophilus. Calculated spectra for both single molecule and the optimized structure of B800 complex containing nine of such molecules are in qualitative agreement with experimental data. The absence of any sizable effects originating from the interaction between adjacent molecules are proved. Thus, optical features of B800 LH2 part are not connected to the structural organization of pigments. The importance of the time-dependent procedure for the correct description of BChl a absorption spectrum is demonstrated.

При помощи нестационарных расчетов на основе теории функционала плотности методами TD-DFT и TD-DFTB исследованы оптические свойства фрагмента B800 светособирающего комплекса 2 (LH2) Rhodoblastus acidophilus. Полученные в результате расчетов спектры поглощения как одиночной молекулы BChl a, так и оптимизированной структуры B800, состоящей из 9 молекул, качественно согласуются с экспериментальными данными. Доказано отсутствие значимых эффектов, обусловленных взаимодействием между соседними молекулами. Таким образом, спектральные особенности B800 не связаны со структурной организацией молекул пигментов. Показана важность нестационарных расчетов для корректного описания спектра поглощения BChl a.

https://doi.org/10.1007/s11051-025-06271-9

The paper provides a comprehensive analytical and numerical examination of the properties of single-domain superparamagnetic magnetite nanoparticles, aiming to devise strategies for selectively damaging the membranes of malignant cells and enhancing anticancer magnetomechanical therapy. It highlights the potential formation of anisotropic aggregates composed of multiple magnetite nanoparticles even in the absence of an external magnetic field. These aggregates, when combined with gold nanoparticles, can selectively bind to mechanoreceptors on the membranes of malignant cells employing aptamers. The aggregation process suppresses thermal fluctuations of the intrinsic magnetic moments of individual particles, thanks to the collective magnetic field generated by the resulting subaggregates. As a result, these nanoparticle aggregates demonstrate stabilization of their total magnetic moment driven by this cooperative behavior. The growth of aggregates of magnetic nanoparticles is accompanied by an increase in the total magnetic moment of the aggregates and the strength of the mechanical effect on cell mechanoreceptors. This enhanced interaction can contribute to the programmed death of malignant cells (apoptosis) in malignant cells when exposed to an alternating magnetic field. The analysis presented makes it possible to explain the experimental results from magnetomechanical therapy utilizing gold and magnetite nanoparticles, which effectively suppresses Ehrlich carcinoma both in vivo and in vitro within an alternating magnetic field. These results affirm the promising potential for implementing this method as a highly effective treatment for malignant tumors.

https://doi.org/10.1007/s10948-025-07025-3

The magnetization of a series of samples containing ε-Fe₂O₃ nanoparticles of different average sizes (approximately 4‒11 nm) has been measured in the temperature range of 300–550 K, which includes the region of a high-temperature magnetic transition. The observed Néel temperature drop has been attributed to the manifestation of the size effect: from ~ 500 K for fairly coarse (> 10 nm) particles to ~ 450 K for particles of ~ 5 nm in size. The obtained particle size dependence of the Néel temperature has been analyzed within the scaling law for critical phenomena in finite-size systems.

https://doi.org/10.1016/j.tsf.2025.140746

The synthesis of vanadium oxide compounds, V₂¹⁸O_3-x, with oxygen non-stoichiometry and heavy oxygen isotope doping (¹⁸O), was achieved via the cathode arc sputtering method. The microstructural characteristics and stoichiometric properties of the resulting nanocrystalline films were examined using X-ray diffraction, atomic force microscopy and Rutherford backscatter spectrometry. The concentration of defects leading to the suppression of the structural and electronic metal-insulator transition was evaluated through Raman spectroscopy and the analysis of electrophysical properties. A semi-empirical simulation of the lattice dynamics of vanadium oxide was also performed. Notable temperature anomalies in resistance, impedance, and relaxation time were observed. A model involving the deformation of octahedra and the splitting of oxygen vacancies multiplets was proposed to explain the formation of impurity subbands. Furthermore, a change in the sign of magnetoresistance and magnetoimpedance at specific temperatures, along with the effect of photoconductivity, was discovered.

DOI 10.3897/j.moem.11.2.141803
The paper studies the effect of high-temperature treatment on structural and magnetic properties of the system MnZn_1-xCr_xSb (0 ≤ x ≤ 0.20) solid solutions obtained by solid-phase reactions with subsequent quenching. It was shown all solid solutions have a tetragonal crystal structure with P4/nmm space group, which is preserved under high-temperature treatment. The temperatures of the magnetic phase transition increase with grow substitution concentration. High-temperature treatment of the initial MnZnSb compound leads to increasing of Curie temperature and coercive force. The effect of substitution concentration on the coercive force and magnetization value has been discovered.

DOI: 10.3367/UFNr.2024.06.039696

Рассмотрены экспериментальные и теоретические результаты по изинговской сверхпроводимости. Данное направление в физике сверхпроводимости началось с обнаружения необычной сверхпроводимости в слоистых дихалькогенидах переходных металлов типа MoS₂ с необычно большими значениями верхнего критического поля B_c2, в шесть раз превышающего парамагнитный предел. Оказалось, что это обусловлено особенностями кристаллической решётки двумерных монослоёв, индуцирующих спин-орбитальные взаимодействия Изинга и Рашбы. Особенности кристаллической структуры приводят к сосуществованию синглетного и триплетного спаривания, а также к топологическим фазам. Обсуждаются варианты поиска майорановских состояний на концах одномерных проводов на поверхности изинговского сверхпроводника.

https://doi.org/10.1134/S1063784225700264

The parameters of a resonator consisting of two dielectric plates with gratings of strip conductors between the layers in the form of squares, and on the outer surfaces in the form of square meshes having the same subwavelength period, have been determined. The quality (Q) factor of the resonator, which has been measured at the normal wave incidence, is determined by the ratio of the widths of the internal and external conductors. Using electrodynamic analysis of a 3D resonator model, the propagation of plane linearly polarized electromagnetic waves when their angle of incidence φ deviates from the normal to the plane of the layered structure has been studied. It is found that for the parallel polarization of the wave, the Q factor of the observed half-wave resonance with increasing φ first drops to a minimum when approaching the Brewster angle, and then increases as φ → 90°. In the case of the perpendicular polarization of the wave, the Q factor of the half-wave resonance gradually increases with increasing φ, approaching the maximum value at φ → 90°.

https://doi.org/10.1134/S0021364025606396

The features of the magnetic structure of ultrasmall �-Fe₂O₃ nanoparticles have been studied by the nuclear forward scattering technique using synchrotron radiation. The sample consists of isolated �-Fe₂O₃ nanoparticles with an average size of ⟨�⟩=3.8 nm immobilized in a SiO₂ xerogel matrix. The time-domain spectra have been measured in the temperature range of 4–300 K in zero external magnetic field and field �=4 T applied in the longitudinal direction. The character of the change in the hyperfine field H_hf as a function of the external magnetic field is the same in the entire temperature range: unlike large �-Fe₂O₃ particles, a monotonic increase in H_hf is observed in the external field. These results indicate that there is no magnetic transition in the temperature range of 80–150 K for ultrasmall (smaller than ≈9 nm) �-Fe₂O₃ particles, and the magnetic structure is noncollinear in the range of 4–300 K.