bluuebunny/crossref_metadata_2025 huggingface dataset:
Recent advances in development of glucose nanosensors for cellular analysis and other applications
Authors: Verkhovnikova Ekaterina N. , Timoshenko Roman V. , Vaneev Alexander N. , Tikhonova Tatiana N. , Fadeev Victor V. , Gorelkin Peter V. , Erofeev Alexander S.
Published: February 2025

Diabetes mellitus is a disease that affects a large number of people around the world.
Fluorescent p53 helix mimetics pairing anticancer and bioimaging properties
Authors: Karmakar Sintu , Mallik Mimasha , Sulava Sushree , Modi Unnati , Allu Suryanarayana , Sangwan Shruti , Tothadi Srinu , Prakasha Reddy J. , Vasita Rajesh , Nangia Ashwini K. , Alone Debasmita Pankaj , Prabhakaran Panchami
Published: February 2025

We report intrinsically fluorescent “hotspot” design-based p53 helix mimetics with dual functions as bioimaging and anticancer agent using cancer models. Selective anticancer activity and cell permeability highlight potential biomedical applications.
Galvanic replacement mediated morphological adjustments boost nanoparticle performance in electrocatalytic alcohol oxidation
Authors: Ma Dongze , Zhao Jin , Jia Jianfeng
Published: February 2025

This article shows how galvanic replacement-driven morphological tuning boosts nanoparticle performance in electrocatalytic alcohol oxidation, enabling scalable, efficient catalyst design for energy applications.
Visible light-induced photoisomerization of indole–oxindole constructs: molecular disassembly and ROS-mediated apoptosis
Authors: Tyagi Kartikay , Dixit Tejal , Venkatesh V.
Published: February 2025

Exclusive synthesis of Z-isomers of the indole–oxindole constructs (IOCs) has been accomplished facilitated by unusual intramolecular hydrogen bonding interaction. Upon 456 nm light irradiation, IOC-4-Z shows Z–E photoisomerization and produces ROS.
Self-encapsulation or picket-fence? An answer to molecular designs of highly solid-state luminescent conjugated polymers
Authors: Sakurai Tsuneaki , Ohkura Kyota , Ikeda Teruyoshi , Terao Rin , Kamimura Yoshiki , Hara Mitsuo , Shimizu Masaki
Published: February 2025

Picket-fence conjugated polymers show higher photoluminescence quantum yields in solid films than the self-encapsulated analogues despite their less bulky substituents.
Rational reconstruction from attapulgite to MCM-41 and its superior application in formaldehyde degradation
Authors: Chen Dan , Zhang Jing , Zhai Ming , Chen Xin , Miao Liqi , Li Kan , Wang Zhong , Wang Xiaozhi
Published: February 2025

1. Catalytic application of MCM-41 can be improved by replacing TEOS with attapulgite. 2. The mechanism of structural transition from attapulgite to MCM-41 was proposed.
Design, synthesis, and redox properties of ferrocene-functionalized phenothiazine and phenothiazine sulfone isomers
Authors: Tiwari Nikhil Ji , Misra Rajneesh
Published: February 2025

The redox-active species of ferrocene-functionalized phenothiazine (PTZ) and phenothiaizne sulfone derivatives show absorption spectra in the Near-Infrared (NIR) region (700–1000 nm).
Ferromagnetism in LaCoO3: relationship between the crystal structure, morphology and magnetic properties
Authors: Orlov Yuri S. , Dudnikov Vyacheslav A. , Vereshchagin Sergey N. , Ustyuzhanin Yuri N. , Nikolaev Sergey V. , Zharkov Sergey M. , Volochaev Mikhail N. , Zeer Galina M. , Gavrilkin Sergey Yu. , Tsvetkov Alexey Yu. , Ovchinnikov Sergey G.
Published: February 2025

Experimental evidence of ferromagnetic ordering caused by near-defect structural stresses is provided.
Thiacalix[4]arene-capped Ln(iii) aggregates with “hand in hand” structures and their luminescence properties
Authors: Gao Hongbo , Wang Hao , Liu Chenxing , Yan Qicao , Wang Yanyan , Wen Herui , You Hongpeng , Hao Zhaomin , Liao Wuping
Published: February 2025

Two isostructural TbIII/EuIII-TC4A aggregates with a “hand in hand” structure were synthesized. TbIII-TC4A complex could effectively avoid fluorescence quenching under different conditions and shows a millisecond level emission lifetime.
Sodium cluster-driven safety concerns of sodium-ion batteries
Authors: Niu Jiaping , Dong Junyuan , Zhang Xiaohu , Huang Lang , Lu Guoli , Han Xiaolei , Wang Jinzhi , Gong Tianyu , Chen Zheng , Zhao Jingwen , Cui Guanglei
Published: February 2025

This study reveals that quasi-metallic sodium clusters in hard carbon possess an electron state density even higher than that of metallic sodium, making them more susceptible to triggering thermal runaway compared to lithium in graphite.
PK 11195 derivatives: Exploring the influence of amide and heterocyclic substitution on A147T TSPO discrimination
Authors: Sokias Renee , Zhao Andrea , Werry Eryn , Montgomery Andrew , Hibbs David , Sullivan Michael , McKenzie André D.J. , Cumbers Grace Arun , Allen Beau M. , Danon Jonathan Joseph , Kassiou Michael
Published: February 2025

The translocator protein (TSPO) is an 18 kDa protein on the outer mitochondrial membrane. It has gained significant interest in recent years for its potential as a therapeutic target and...
Green mechanochemical fabrication of graphite-lanthanide oxide nanocomposites
Authors: Acevedo-Guzmán Diego A. , Monroy-Torres Brian , Rudolf Petra , Basiuk Vladimir A. , Basiuk Elena V.
Published: February 2025

Ball milling of graphite allows the obtention of few-layered graphene and the surface functionalisation with lanthanide ions in a one-step process without increasing the cytotoxicity.
Docetaxel-conjugated bile acid-derived nanomicelles can inhibit tumour progression with reduced toxicity
Authors: Mehta Devashish , Dua Chhavi , Chakraborty Ruchira , Yadav Poonam , Dasgupta Ujjaini , Bajaj Avinash
Published: February 2025

In this study, we aimed to enhance the tolerability and reduce the toxic effects of DTX by developing a novel hybrid scaffold (PIP-LCA-DTX), where we conjugated DTX to piperidine-derived lithocholic acid.
Copper-anchored polysulfonamide-modified UiO-66-NH2/sodium alginate nanocatalyst for sustainable synthesis of 1,2,3-triazoles
Authors: Koosha Samaneh , Ghorbani-Vaghei Ramin , Alavinia Sedigheh
Published: February 2025

An effective nanocomposite comprising a metal–organic framework and porous polysulfonamide-sodium alginate (SA-PS) was developed for phenyl triazole production.
Design, synthesis, insecticidal activity, and mechanism of novel diamide derivatives containing acylthiourea targeting insect ryanodine receptors
Authors: Peng Jinmin , Zhao Yangyang , Xie Weibin , Li Peizhuo , Chen Yue , Liu Jieyin , Yuchi Zhiguang , Liu Jingbo , Li Yuxin
Published: February 2025

The control of lepidopteran insects poses a significant challenge to the sustainable development of agriculture and forestry.
Microstructure and thermoelectric properties of Mg3(Bi,Sb)2 films containing a Mg metal phase
Authors: Luo Di , Song Guihong , Zhang Lingyu , Wu Yusheng , You Junhua
Published: February 2025

Mg–Bi–Sb films with different Mg contents were prepared by magnetron sputtering on single-crystal Si(100) substrates containing 500 nm thick silicon oxide.
DNA origami-templated individual gold nanoclusters: probing their photophysical dynamics using single-molecule fluorescence spectroscopy
Authors: Rai Shikha , Kaur Vishaldeep , Kaur Charanleen , Sharma Mridu , Sen Tapasi
Published: February 2025

Understanding the photophysical properties of single Au NCs on DNA origami by single-molecule confocal fluorescence microscopy.
High-valent oxovanadium metallosupramolecular species as catalysts for the oxidation of benzyl alcohol derivatives
Authors: Topić Edi , Sarjanović Josipa , Musija Danijela , Mandarić Mirna , Hrenar Tomica , Pisk Jana , Vrdoljak Višnja
Published: February 2025

By conducting thorough synthetic and structural characterization studies, and catalytic performance analyses, this research offers valuable insights into oxovanadium(v) metallosupramolecular chemistry.
Donor modulation brings all-in-one phototheranostics for NIR-II imaging-guided type-I photodynamic/photothermal synergistic cancer therapy
Authors: Ren Yuxin , Zhang Xinyi , Li Ling , Yuan Qiong , Bao Benkai , Li Meiqi , Tang Yanli
Published: February 2025

A novel all-in-one phototheranostics OTAB was synthesized by modifying the donor and regulating the band gap for NIR-II imaging-guided synergistic type-I PDT/PTT therapy.
Vacancy induced dissociation of hydrogenized CO2 for promoted CH4 production in MBenes
Authors: Chen Tianyang , Gao Ya , Guo Zhonglu , Wang Erpeng , Zhou Jian , Sun Zhimei
Published: February 2025

Cleavage of C–O bond during the first hydrogenation step leads to high selectivity for CH4 production.
Geminal-Cu catalysts drive efficient C–C coupling to boost ethylene production via electrochemical CO2 reduction
Authors: El-Aqapa Hisham G. , Khedr Ghada E. , Badawy Ibrahim M. , Agour Ahmed M. , Abdelmohsen Abdelrahman M. , Allam Nageh K.
Published: February 2025

Geminal copper electrocatalysts demonstrated promising activity towards the CO2RR particularly in *CO dimerization into ethylene.
Reduction of RuO2 nanoparticles supported on silica by organic molecules: a strategy for nanoparticle redispersion
Authors: Fraga Gabriel , Konarova Muxina , Massin Laurence , Deshan Athukoralalage Don K. , Rackemann Darryn , Laycock Bronwyn , Pratt Steven , Batalha Nuno
Published: February 2025

A detailed study of reduction of supported RuO2 nanoparticles by organic molecules. The relationship between reduction heat, reaction products, nanoparticle dispersion, and catalytic activity was investigated.
Construction of a robust cathode protection layer inspired by the wet adhesion behavior of mussels towards high-performance aqueous zinc-ion batteries
Authors: Gou Qianzhi , Zhang Sida , Mei Huaping , Liu Chang , Luo Haoran , Wang Kaixin , Hu Yuzhi , Song Bingye , Zheng Yujie , Qiao Mingtao , Li Meng
Published: February 2025

Inspired by the wet adhesion behavior of mussels, a polydopamine layer with high conductivity and robust mechanical stability was decorated onto an MnO2 cathode to enhance the electrochemical performance of aqueous zinc-ion batteries.
High-performance anion exchange membrane fuel cells and zinc–air batteries enabled by a hierarchically porous hollow Fe/N/C aerogel catalyst
Authors: Wang Liqiang , Zhong Jiang , Fu Yanqing , Wu Fen , Wang Sen , Li Jie , Yu Han , Shi Qing , Liu Qiao , Yu Ruizhi , Wu Bing , Sofer Zdenek , Zheng Kun , Yang Weiyou , Wei Qiliang
Published: February 2025

This study designs a porous hollow Fe/N/C aerogel catalyst to boost electrochemical performance in AEMFCs and ZABs, emphasizing porous structure optimization for single-cell performance and the transition from half-cell to single-cell evaluations.
Polythiophene-derived nickel cobaltite nanocomposites showing excellent photo-switching and photo-assisted enhanced supercapacitor properties
Authors: Basak Udayan , Ghosh Purnadas , Chatterjee Dhruba P. , Mahapatra Gouranga , Banerjee Arindam , Nandi Arun K.
Published: February 2025

A solid-state photo-assisted supercapacitor from a polythiophene derivative and spinel NiCo2O4 exhibits a specific capacitance 106 F g−1, an increased rate capability of 10.6% and cyclic stability of 5% under UV-light compared to dark conditions.
III–V semiconductor wires for optical switches in solid-state lasers
Authors: Qiu Linlu , Zhao Yifan , Jiang Jieyu , Lou Fei , Zhang Shuaiyi , Yang He , Zhang Baitao , Wang Xia , He Jingliang
Published: February 2025

This paper reviews the recent advancements of III–V semiconductor wires as optical switches in solid-state lasers, while addressing the impact of factors such as strain and diameter on their electronic structure and thermal conductivity.
Phenazine-based non-fused electron acceptors for high-performance organic solar cells
Authors: Wang Tingting , Li Wenliang , Xu Jie , Hu Chaokang , Luo Wenli , Zhao Xiaohong , Hu Yu , Yuan Zhongyi
Published: February 2025

Excellent low-cost non-fused ring electron acceptors (NFREAs) are important for future large-scale application of bulk heterojunction organic solar cells (BHJ OSCs).
Platinum(ii) complexes of aryl guanidine-like derivatives as potential anticancer agents: between coordination and cyclometallation
Authors: O'Sullivan Patrick , Previtali Viola , Twamley Brendan , Marmion Celine J. , McDonald Aidan R. , Rozas Isabel
Published: February 2025

The preparation of a wide variety of Pt(ii) complexes with aryl guanidines and their potential application as anticancer agents have been explored.
Opportunities, challenges and requirements for introducing space division multiplexing in fibre optical networks
Authors: Di Rosa Gabriele , Rapp Lutz
Published: February 2025

In the long‐term, enabling data transmission over additional wavelength bands offered by the installed fibre infrastructure is not sufficient to satisfy the continuously increasing demand for capacity. In order to be prepared for future requests, space‐division multiplexing (SDM) is moving into the focus of commercial equipment manufacturers and providers. Different options are pointed out and basic design features for new fibres are explained, in particular in view of multi‐core fibres. In this regard, emphasis is put on detailing the importance of different geometrical parameters. Commercial deployment of SDM technology requires to bring cost down to a competitive level, which cannot be achieved with new fibres alone but requires the development of new kinds of components. Approaches to bring down cost for optical amplifiers, transceivers, and wavelength‐selective switches are presented. Finally, an upgrade scenario for introducing SDM in commercial networks is discussed.
Homology reveals significant anisotropy in the cosmic microwave background
Authors: Pranav Pratyush , Buchert Thomas
Published: February 2025

We test the tenet of statistical isotropy of the standard cosmological model via a homology analysis of the cosmic microwave background (CMB) temperature maps in galactic coordinates. The map pixels were normalized by subtracting the mean and rescaling by standard deviation, both of which were computed from the relevant unmasked pixels. Examining small sectors of the normalized maps, we find that the results exhibit a dependence on whether we compute the mean and variance locally from the non-masked patch, or from the full masked sky. Assigning local mean and variance for normalization, we find the maximum discrepancy between the data and model in the northern hemisphere, at more than $3.5$ standard deviations (s.d.) for the PR4 dataset at degree scale. For the PR3 dataset, the C-R and SMICA maps display a higher significance than the PR4 dataset at ∼ 4 and $4.1$ s.d., respectively; however, the NILC and SEVEM maps present a lower significance at ∼ 3.4 s.d. The discrepancy is most prominent at scales of roughly a degree, which coincides with the physical scale of the horizon at the epoch of the CMB. The southern hemisphere exhibits a high degree of consistency between the data and the model for both the PR4 and PR3 datasets. Assigning the mean and variance of the full masked sky decreases the significance for the northern hemisphere; in particular, the tails. However, the tails in the southern hemisphere are strongly discrepant at more than $4$ standard deviations at approximately $5$ degrees. The p values obtained from the χ^2-statistic show commensurate significance in both experiments. Examining the quadrants of the sphere, we find the northwest quadrant of the Galactic frame to be the major source of the discrepancy. Prima facie, the results indicate a breakdown of statistical isotropy in the CMB maps; however, more work is needed to ascertain the source of the anomaly. Regardless, these map characteristics may have serious consequences for downstream computations and parameter estimation, and the related problems of Hubble and σ_8 tension.
Dipolar fluence distribution of statistically isotropic FERMI gamma-ray bursts
Authors: Lopes Maria , Bernui Armando , Hipólito-Ricaldi Wiliam S. , Franco Camila , Avila Felipe
Published: February 2025

Aims. We investigated the large-angle distribution of the gamma-ray bursts (GRBs) from the updated FERMI/GBM catalog to probe the statistical isotropy of these astrophysical transient events. We also studied the angular distribution of the GRB fluence as a way to explore whether this radiative feature shows some preferred direction on the sky that suggest their origin.

Methods. Our model-independent approach performed a directional analysis of the updated FERMI/GBM catalog. The statistical significance of our results is obtained by comparison with a large set of statistically isotropic samples of cosmic objects, with the same features of the FERMI data.

Results. Our analyses confirm that the angular distribution of the FERMIGRB is statistically isotropic on the celestial sphere. Moreover, analyzing the directional distribution of the FERMIGRB fluence, that is, the median GRB fluence in a set of directions that scans the celestial sphere, we found that this astrophysical property exhibits a net dipolar structure with a directional preference for latitudes near the Galactic plane. However, additional studies show that this directional preference is not correlated with the Milky Way Galactic plane, which suggests that the GRB dataset, and its fluence dipolar structure, are extra-Galactic in origin. Interestingly, the analyses of the BATSE Channel 4 fluence data, that is, those GRBs from BATSE with energy > 300 keV, reveal that its dipole direction is very well aligned with the cosmic microwave background dipole.
Gamma rays from star clusters and implications for the origin of Galactic cosmic rays
Authors: Blasi Pasquale
Published: February 2025

Context. Star clusters are often invoked as contributors to the flux of Galactic cosmic rays and as sources potentially able to accelerate particles to ∼Peta-electronVolt energies. The gamma radiation with E ≳ 1 TeV recently observed from selected star clusters has profound implications for the origin of Galactic cosmic rays.

Aims. We show that if the gamma rays observed from the Cygnus cocoon and Westerlund 1 are of hadronic origin, then the cosmic rays escaping the cluster at energies ≳10 TeV must cross a grammage inside the cluster that exceeds the Galactic grammage. At lower energies, depending on the model adopted to describe the production of gamma rays, such grammage may exceed or be comparable with the grammage inferred from propagation on Galactic scales.

Methods. We analytically computed the flux of gamma rays for a few models of injection of cosmic rays in star clusters and compared it with the flux measured from selected clusters.

Results. In all the models considered here, comparing the inferred and observed gamma ray fluxes at E ≳ 1 TeV, we conclude that CRs must traverse a large grammage inside or around the cluster before escaping. Clearly these implications would not apply to a scenario in which gamma rays are produced due to radiative losses of leptons in the cluster. Leptonic models typically require weaker magnetic fields, which in turn result in maximum energies of accelerated particles much below ∼1 PeV.

Conclusions. We conclude that if gamma ray emission in SCs is a generic phenomenon and if this radiation is due to hadronic interactions, either star clusters cannot contribute but a small fraction of the total cosmic ray flux at the Earth or their contribution to the grammage cannot be neglected, and the paradigm of Galactic transport should be profoundly revisited.
New insights with XRISM and Cloudy: A novel column density diagnostic
Authors: Gunasekera Chamani M. , van Hoof Peter A. M. , Tsujimoto Masahiro , Ferland Gary J.
Published: February 2025

Aims. We present a simple yet powerful column density diagnostic for plasmas enabled by X-ray microcalorimeter observations.

Methods. With the recent developments of the spectral simulation code CLOUDY, inspired by the high spectral resolution of the X-Ray Imaging and Spectroscopy Mission (XRISM) and the Advanced Telescope for High Energy Astrophysics (Athena), we make predictions for the intensity ratio of the resolved fine-structure lines Lyα1 and Lyα2 of H-like ions.

Results. We show that this ratio can be observationally constrained and used as a plasma column density indicator. We demonstrate this with an XRISM observation of the high-mass X-ray binary Centaurus X-3.

Conclusions. This diagnostic is useful for a wide range of X-ray emitting plasmas that are either collisionally or radiatively ionized.
Sodium Hypochlorite Pentahydrate as an Environmentally Benign Oxidizing Agent: Effective Synthesis of Carboxylic Acids from Primary Alcohols and Sulfones from Sulfides
Authors: Kirihara Masayuki , Shimazu Hideo , Kawai Takuma , Kinoshita Yukari , Sakamoto Yugo , Akiyama Tomomi , Osugi Eri , Kikkawa You , Okada Tomihide , Kimura Yoshikazu
Published: February 2025

The oxidation of primary alcohols, sulfides, and trifluoromethyl sulfides using sodium hypochlorite pentahydrate crystals as the oxidizing agents was investigated in detail. The optimal conditions for the oxidation of the corresponding carboxylic acids, sulfones, trifluoromethylsulfones in high yields were determined. By adjusting the pH of the reaction medium to 9–10, the primary alcohol in ethyl acetate and water in the presence of TEMPO or AZADOL was oxidized to aliphatic and aromatic carboxylic acids in high yields. The sulfide was oxidized to sulfone in high yield using toluene as the solvent, and trifluoromethyl sulfide was oxidized to give the corresponding sulfone in benzotrifluoride in the presence of trifluoroacetic acid.
Threshold magnetic field effect in YBa2Cu3O7–x single-crystals
Authors: Lazarev B. G. , Lazareva L. S. , Chupikov A. A. , Obolenskiĭ M. A. , Bondarenko A. V.
Published: February 2025

A new phenomenon has been found in studies of the electrical resistance of YBa2Cu3O7–x single crystals (with Tc = 90.2 °K and ΔTc ≈ 0.2 °K); two states are observed, depending on the magnitude of the applied field, which differ sharply in the appearance of the superconducting transition curves and in the value of the normal resistance. The transition from one state to the other takes place abruptly at a certain threshold value of magnetic field.
Shubnikov–de Haas oscillations in organic metals
Authors: Kartsovnik M. V. , Laukhin V. N. , Pesotskiĭ S. I.
Published: February 2025

Experimental results obtained to date in the investigation of Shubnikov–de Haas oscillations in low-dimensional organic metals and superconductors are surveyed.
Defect formation stimulated by exciton self-trapping into quasimolecular states of xenon cryocrystals
Authors: Fugol’ I. Ya. , Ogurtsov A. N. , Grigorashchenko O. N. , Savchenko E. V.
Published: February 2025

A detailed study has been made of excimer radiation from crystalline xenon excited by subthreshold energy electrons. A structural distortion-induced component has been identified. From dose dependence measurements the existence has been inferred of low-temperature mechanisms of defect formation stimulated by electron subsystem excitation. It is shown that stable defects are formed both at the stage of self-trapping into quasimolecular states, and after their radiation decay.
Nonlinear excitation of viscous waves in superfluid helium
Authors: Pushkina N. I.
Published: February 2025

The problem of the nonlienar production of a transverse viscous wave by second sound in helium II is solved. The possibility of experimental realizing such an interaction experimentally is assessed.
Relaxation of excitonic excitations in high-temperature superconductors
Authors: Gaididei Yu. B. , Loktev V. M.
Published: February 2025

Starting from the assumption that optical dd-transitions in high-Tc superconducting compounds correspond to the excitation of boundstates of electrons and holes (excitons), we study the relaxation of excitons on free carriers. It is shown that the experimentally observed temperature dependence of the absorption (transmission) intensity with excitation of excitons (initially 3d9→3d9 transitions in Cu2+ ions) can be associated with a superconducting transition in a two-dimensional metalized system of free carriers.
Anomalous effect of a helium film on the interaction of electrons with surface defects of solid hydrogen
Authors: Monarkha Yu. P.
Published: February 2025

It is established that the Hamiltonian describing the scattering of surface electrons by surface nonuniformities of solid hydrogen depends nonmonotonically on the thickness of the condensed helium film. It is shown that by smoothing the surface defects the helium film can intensify the interaction of electrons with them. The results obtained are employed to explain the experimentally observed anomalies in the electron mobility above solid hydrogen.
Effect of an increase in the lower critical field in the superfine-grained high-T
c superconductor YBa2Cu3O7–δ
Authors: Mamsurova L. G. , Pigal’skiĭ K. S. , Shlyakhtina A. V. , Shcherbakova L. G.
Published: February 2025

The field dependences of the dynamic magnetic permeability of the superconducting ceramic YBa2Cu3O7–δ with various degrees of dispersion have been studied. The lower critical field of grains of superfine-grained ceramics are shown to be considerably higher than those of coarse-grained samples.
Angular dependence of the reflection coefficient for intravalley electron scattering at a bismuth surface
Authors: Andrievskii V. V. , Rozhok S. V.
Published: February 2025

We have studied intravalley conduction electron scattering processes at the surface of a bismuth crystal with a specularly reflecting surface, using the method of focused electrons, and we have determined the angular dependence of the specular reflection coefficient corresponding to this scattering. The dependence found corresponds to the geometry of the experiment, which excludes any contribution of intervalley scattering processes.
On the theory of roton-limited mobility of charges in He II
Authors: Bondarev V. N. , Kuskovskii I. L.
Published: February 2025

The concept of localized rotons is used to calculate their contribution to the ion drag force in He II in the roton temperature region. For the first time, a consistent explanation is provided for the experimentally observed increase in the negative ion mobility with the drift velocity in weak electric fields. A large body of experimental data on the temperature and pressure dependence of ion mobility is also analyzed. It is shown that a good agreement between the theoretical and experimental results can be obtained for quite realistic values of the ion-roton system parameters. It is suggested that the concept of roton localization in the vicinity of ions may be developed further in subsequent experimental investigations.
Problems of texturized and epitaxial HTS film formation by pulsed laser ablation technique
Authors: Usoskin A. I. , Chukanova I. N.
Published: February 2025

Problems associated with the pulsed laser ablation technique of film deposition on crystalline substrates are analyzed, and physical mechanisms of the film growth process, which can be used for attaining a qualitatively new level of technology, are revealed.
Investigations of YBa2(Cu1–xFex)3O7–δ oxide system in strong magnetic fields
Authors: Asadov S. K. , Zavadskii É. A. , Rassokhin S. N. , Todris B. M.
Published: February 2025

The magnetic and superconducting properties of the YBa2(Cu1–xFex)O7–δ (0 ≤ x ≤ 0.12) oxide system are studied in the temperature interval 4.2–100 K. The temperature dependence of the susceptibility in a constant magnetic field up to 130 kOe and the field dependences of magnetization recorded in pulsed fields up to 250 kOe are used to estimate the upper critical field and to determine the critical current density. It is found that the irreversible component of magnetization does not change with increasing iron concentration in compounds with x > 0.06.
The role of protons in the pyroelectric anomalies of TGS single crystals with defects at T=1.5–10 K
Authors: Esengaliev A. B. , Novik V. K. , Novikov V. N. , Gavrilova N. D. , Drozhdin S. N.
Published: February 2025

An attempt is made to find the mechanism of the formation of the anomalous low-temperature behavior discovered earlier in the pyroelectric coeffient of different TGS single crystals. It is established that the anomalous behavior of the pyrocoefficient in the region T < 10 K is due to the ordered localization of an impurity-delocalized proton at the surplus hydrogen bond as T→0. The surplus hydrogen bonds in TGS crystals appear due to the presence of charged ligands. Anomalies at higher temperatures are associated with heavier atoms of the crystal structure. Changes in the pyroelectric properties under the influence of different doses of γ-radiation are studied. The concept of “large” and “small” doses is introduced. “Small” doses do not change the lattice vibration spectrum responsible for pyroelectricity, while “large” doses cause its modification which is followed by structure amorphization. The methods of controlling the pyroelectric properties of hydrogen-containing ferroelectric compounds at low and ultralow temperatures by creating impurities and radiation defects in the structure are indicated.
Ultrasonic spectroscopy of a La2CuO4 crystal in the vicinity of the tetra–ortho phase transition
Authors: Makarov V. I. , Vereshkov G. M. , Gufan Yu. M.
Published: February 2025

The processing of experimental data on the propagation of sound in La2CuO4 in the vicinity of the structural tetra–ortho transition makes it possible to determine the type and properties of the soft phonon mode responsible for the phase transition and the type of unit cell deformation.
Computer simulation of the atomic structure of twin boundaries in the high-T
c superconductor YBa2Cu3O7
Authors: Boiko V. S. , Sidorenko I. N. , Mazilova T. I.
Published: February 2025

Computer simulation of the atomic structure of the mirror twin (110) and pseudotwin boundaries in the lattice of high-Tc superconductor YBa2Cu3O7 is carried out. The effect of the atomic structure of twin boundaries on superconductivity is considered.
Metallic point contacts realized by nanofabrication techniques
Authors: Caro J. , Holweg P. A. M. , Verbruggen A. H. , Kokkedee J. A. , Radelaar S.
Published: February 2025

Recently, metallic point contacts gained renewed interest as a result of the development of a fabrication technique which produces very stable devices suitable for studies of reproducible, sample dependent (mesoscopic) properties. In this paper our fabrication technique for point contacts is presented and recent results are reported on point-contact spectra of Al, Cu, Ag and Au, two-level resistance fluctuations due to defect motion in an Au point contact and conductance fluctuations as a function of magnetic field and bias voltage in Ag point contacts.
Classical correlation phenomena in point contacts: classical mesoscopics, disorder induced flicker noise and dynamical chaos
Authors: Gal’perin Yu. M. , Kozub V. I.
Published: February 2025

Effects connected with correlation between purely classical electron trajectories are considered. It is shown that the correlation between successive acts of scattering by defects or impurities leads to a conductance behavior similar to quantum mesoscopic effects (universal conductance fluctuations), namely: conductance fluctuations due to shifts of given scatterers and stochastics “glass-like” conductance dependence on an external magnetic field. The presence of scatterers with internal degrees of freedom (“fluctuations”) leads in structurally disordered regions to low-frequency noise with a flicker spectrum which for small-size contacts is decomposed into a sum of Lorentian functions. The influence of a dynamical chaos of electron trajectories in systems containing two point contacts in series is also discussed.
Point-contact spectroscopy of α
t-(BEDT-TTF)2I3: an alternative interpretation
Authors: Weger M. , Nowack A. , Schweitzer D.
Published: February 2025

We report on point-contact measurements on the organic superconductor αt-(BEDT-TTF)2I3 (Tc ≈ 8 K). The dV/dI vs V characteristics of homocontacts of this material show strong nonlinearities which, interpreted as a gap-structure, lead to extremely high values of Δ/kTc. Among other possibilities, we discuss the anomaly in terms of a strongly enhanced McMillan–Rowell structure Δ(ε) at ε = ΔBCS + ωph. The enhancement is caused by deviations from the Eliashberg equations due to strong coupling (λ = 1−2) together with an Einstein phonon spectrum.
Point-contact spectroscopy of superconductors
Authors: Omelyanchouk A. N.
Published: February 2025

The theoretical grounds of point contact spectroscopy of metals in the case where one or both the electrodes are in the superconducting state are presented. The primary focus is on the effects of strong electron–phonon interaction1 and on specific features of spectroscopy of high-temperature superconductors.2

The Josephson effect,3 spectroscopy of nonequilibrium phonons and elastic contact spectroscopy of electron–phonon interaction in metals,4 influence of depairing factors on nonlinear conductivity5 are reviewed.
Temperature-dependent point-contact characteristics of YBa2Cu3Ox–Ag
Authors: Rybaltchenko L. F. , Hohn N. , Müller R. , Borowski R. , Büchner B. , Schäfer W. , Wohlleben D. , Yanson I. K.
Published: February 2025

We have studied the electrical characteristics of YBa2Cu3Ox−Ag point contacts with 6.55 ≤ x ≲ 7.0 between 4.2 K and Tc. The zero-bias resistance was about 10 Ohm. The differential resistance dV/dI(V) showed the Andreev reflection behavior, from which we extracted the gap value Δ and its temperature dependence Δ(T). At 4.2 K the gap varies from Δ0 = 39 meV for the largest x to Δ0 = 4.3 meV for the smallest x. It is found that the gap value goes down with decreasing oxygen content much faster than Tc; this imples a change of the ratio 2Δ/kTc from ∼ 12 to ∼ 2 when the oxygen content decreases from the maximum magnitude to the minimum one.
Spectroscopy of N–S and S–S point contacts
Authors: Asen M. , Keck K.
Published: February 2025

Mechanically point contacts (pc) made of Ta, Al, Ag (anvil) and of Ta, Ag (needle) were investigated in the temperature range between 4.2 and 1.3 K and in magnetic fields up to 0.8 T. The measured dynamic conductance dI/dV(V) and the current–voltage characteristics of all N–S and S–S point contacts suggest a normal-conducting–superconducting microconstriction contact, including a barrier of arbitrary strength at the interface. A possible explanation for our results can be the appearance of Andreev single-reflection, occurring at the NS boundaries in the contact area. For point contacts of two superconducting banks we also obtained dI/dV characteristics that can be explained by Andreev multiple-reflection at SNS interfaces inside the point contact region. The discovered negative differential conductance in the current–voltage characteristics and the presence of an excess current for higher voltages point to Andreev multiple-reflection.
Tunneling into the BiSrCuO superconductor up to the critical magnetic field
Authors: Samuely P. , Vedeneev S. I. , Jansen A. G. M. , Kazakov I. P. , Gonnelli R.
Published: February 2025

Tunneling effect on the BiSrCuO superconductor with the critical temperature Tc = 10 K has been measured up to 10 T. Using superconducting Nb as a counter electrode, the successive transition from the superconducting–superconducting, to the superconducting–normal, and to the normal-normal tunnel junction has been observed in the critical magnetic field of Nb and that of BiSrCuO, respectively. The broadened BCS density of states fits the normalized conductance data.
Conductance of a point contact in two-dimensional electron gas with high bias
Authors: Fedirko V. A. , Ryzhii V. I. , V’yurkov V. V.
Published: February 2025

The differential conductance of a narrow channel in two-dimensional electron gas undergoes steplike variations as the bias rises. The conductance of the channel at higher bias may be much smaller than 2e2/h and is determined by the space charge arising at the channel ends. The space charge may also cause current instability.
Hole frustration contribution to the magnetic susceptibility of CuO2 layers in high-temperature superconductors
Authors: Bogdan M. M. , Kovalev A. S. , Stepanov A. A.
Published: February 2025

The contribution of frustrations to the magnetization and the magnetic susceptibility of the antiferromagnetic CuO2 layers in high-Tc compounds has been calculated within the framework of a planar Heisenberg model with frustrated bonds. The found relationships are discussed in connection with the weak ferromagnetism observed in compounds of the R2CuO4 type.
Supersaturation of 3He–4He superfluid solutions in the phase separation region
Authors: Maidanov V. A. , Mikheev V. A. , Mikhin N. P. , Omelaenko N. F. , Rudavskii É. Ya. , Chagovets V. K. , Sheshin G. A.
Published: February 2025

Two independent experiments have been carried out to study the peculiarities of phase separation in 3He–4He liquid solutions in the temperature range 30–250 mK. In the first experiment, the separation was initiated through an increase in the concentration and detected from a change in the first sound velocity and the dielectric constant. The second experiment used the decompression method for initiation and pulsed NMR technique for detection. The obtained temperature dependence of the supersaturation is quantitatively in accord with the predictions of the theory based on the thermal activation mechanism of nucleation. Results of different experiments are found to vary at low temperatures. Data are also obtained for the equilibrium phase separation curves of solutions at low temperatures and under increased pressures.
Nonlinear excitations in superconductor with vector order parameter
Authors: Ivanchenko Yu. M. , Filippov A. E. , Radievsky A. V.
Published: February 2025

The behavior of the effective free energy of a superconductor with a vector order parameter is studied near the stability boundaries. It is shown that the localized non-linear excitations develop in this region of the parameters. The excitations obtained are discussed as a probable physical reason behind fluctuation-induced first-order phase transition.
Investigation of spatial inhomogeneity in the resistive response of N–S boundary by scanning laser probe technique
Authors: Dmitrenko I. M. , Zhuravel’ A. P. , Sivakov A. G.
Published: February 2025

Laser probing technique is used to study the local dependences of the resistive response of the N–S boundary to laser radiation over a wide range of currents and temperatures. It is shown that the spatial characteristics of the response qualitatively reflect the behavior of the nonequilibrium region connected with the N–S boundary. It is proposed that the N–S boundary be used as a coordinate-sensitive microdetector of optical radiation.
Structural and superconducting properties of high quality YBCO films with different orientations
Authors: Andreone A. , Di Chiara A. , Fontana F. , Granozio F. Miletto , Peluso G. , Scotti di Uccio U. , Valentino M.
Published: February 2025

High-quality YBCO thin films with different orientations have been grown by inverted cylindrical magnetron sputtering (ICMS) deposition on LaAlO3 (100), SrTiO3 (100), SrTiO3 (110), and MgO (100) substrates. Best samples show transition temperatures Tc0 = 92 K and transition width ΔTc = 0.5 K. Critical current density measurements have been performed yielding values as high as 5 · 106 A/cm2 at 77 K. Surface resistance of a typical sample is 500 μΩ at 4.5 GHz and 4.2 K. Films with highly preferred α-axis orientation and critical temperatures of about 70 K have been obtained on LaAlO3 (100) and SrTiO3 (100) substrates. The dependence of orientation on deposition temperature has been carefully studied on different substrates. A possible explanation of experimental data regarding film orientation in terms of surface energies and growth dynamics is examined.
Thermodynamic oscillations and Landau absorption under dynamic localization of electrons in superlattices
Authors: Gvozdikov V. M.
Published: February 2025

It is shown that the mean velocity and the effective band width of electrons associated with their motion across the layers of a superlattice (SL) in the field of an electro-magnetic wave having a frequency ω and amplitude E0 and polarized along the SL axis are proportional to the Bessel function J0(ν/ω) for an arbitrary transverse energy-momentum relation (ν = eE0L/ħ is the frequency of Bloch oscillations and L the superlattice period). In the case when the ratio ν/ω coincides with a root of the Bessel function, the mean band velocity of electrons is zero, which corresponds to dynamic electron localization across the layers. By varying ν/ω, we can effectively control the interlayer coupling without a mechanical action on the SL. The effect is manifested in the modulation of frequencies of the de Haas–van Alphen oscillations and in “giant oscillations” (proportional to the one-dimensional density of states) of the Landau collisionless absorption coefficient in SL.
Superconductivity enhancement at the surface of Y1–xPrxBa2Cu3O7–δ ceramic in strong electric fields
Authors: Varyukhin V. N. , Gomenyuk Yu. V. , Lozovskii V. Z. , Lysenko V. S. , Tyagul’ski I. P.
Published: February 2025

We studied the effect of an electrostatic field applied to the surface of ceramic samples of the high-TcY1–xPrxBa2Cu3O7–δ (x = 0.1–0.4) in a metal-insulator structure on the transition temperature to the superconducting state, Tc, as well as on the temperature dependence of the critical magnetic field Hc2 near Tc. An enhancement of superconducting properties under the action of a negative field was found. The results are explained as being due to a field-induced enrichment of the sample surface in charge carriers and in local piezoelectric stresses in the subsurface layer.
Changes in diamagnetic susceptibility and critical current of the superconducting Bi1.6Pb0.4Sr2Ca2Cu3Oy ceramic caused by mechanical stresses
Authors: Dolgin A. M. , Smirnov S. N. , Natsik V. D. , Kononyuk I. F.
Published: February 2025

We studied field dependence of the real (χ′) and imaginary (χ″) parts of the dynamic magnetic susceptibility as well as the sensitivity dχ′/dσ of the real part of the susceptibility χ′ to uniaxial mechanical stress σ ⩽ 60 MPa in Bi1.6Pb0.4Sr2Ca2Cu3Oy, ceramic samples at 4.2 and 77 K. Analysis of experimental data within the framework of a model of critical state allowed us to obtain field dependences of the critical current Ic (controlled by intergrain links) and of the effective fraction of the superconducting phase. The derivatives d In Ic/dσ have been determined to show that the obtained values can be accounted for within the theory of SNS junctions. A new effect has been found: a change in the character of the field dependence of the critical current, the derivative d In Ic/dσ, and the fraction of superconducting phase in the field Bmax corresponding to the maximum of hysteretic losses. The said anomalies are ascribed to changes in the topology of the screening currents, viz., to a separation of the sample into individual superconducting clusters in fields B > Bmax.
Manifestation of a superconducting gap in the optical absorption of superconductors YBa2Cu3O7–δ and Bi2Sr2CaCu2O8 in the visible spectral range
Authors: Fugol’ I. Ya. , Samovarov V. N. , Ratner A. M. , Zhuravlev V. M. , Saemann-lschenko G. , Lippert M. , Holzapfel B. , Mayer O.
Published: February 2025

The manifestation of a superconducting gap was observed experimentally in the temperature dependence of the absorption coefficient κ at a frequency fixed in the interval 1.5–3.0 eV. The temperature dependence of κ has a kink at the point Tc: above Tc, it displays a linear dependence, while below Tc it has a singularity mainly repeating the temperature dependence of the gap. The observed effects are of an equilibrium nature and are interpreted in terms of equilibrium electron characteristics.
High-efficient spin injection in Co/GeSn with ferromagnetic resonance driven spin pumping
Authors: Weng Yi-Chien , Lee Kuo-Chih , Cheng Hung-Hsiang , Lin Jauyn Grace
Published: February 2025

Germanium tin (GeSn) is one of the candidates for spintronic materials owing to its tunable spin–orbit interaction and barrier height with increasing the Sn content. However, as a potential spintronic material, its spin related properties have not been fully understood yet. We investigate the efficiency of spin current detection in GeSn by using the technique of ferromagnetic resonance drive spin pumping. Some fundamental spintronic parameters can be extracted from our experimental results to measure the change of spin injection/conversion efficiency. A Co layer is deposited on the top GeSn thin films to serve as the spin current generator. Here, the effective spin mixing conductance (geff↑↓) and the product of spin diffusion length and spin Hall angle [λsθISHE(%)] represent the spin injection efficiency and the spin-charge conversion efficiency, respectively. geff↑↓ and λsθISHE(%) are 9.3 × 1019 m−2 and 1.39 nm for p-type GeSn; and 7.4 × 1019 m−2 and 2.09 nm for n-type GeSn. The high-efficient spin injection in both p-type and n-type Co/GeSn systems is attributed to a low barrier height at the Co/GeSn interface because the spin current at the interface is proportional to the square root of barrier height. Our experimental results show that GeSn is effective as a spin current sink.
Misfit accommodation in a single interface atomic layer at a highly lattice-mismatched InN/GaN
Authors: Nagase Tomoki , Chokawa Kenta , Kano Emi , Fukuta Keisuke , Sasaki Takuo , Fujikawa Seiji , Takahashi Masamitsu , Shiraishi Kenji , Oshiyama Atsushi , Araki Tsutomu , Ikarashi Nobuyuki
Published: February 2025

Heterostructures of covalent semiconductors provide an invaluable platform for synthesizing the distinct properties of materials, leading to unprecedented functions in electronic and optoelectronic devices. The main challenge has been to forge high-quality interfaces of the heterostructures that guarantee the designed properties. To date, high-quality interfaces have been attained in heterostructures with a lattice mismatch of less than a few percent. However, for highly lattice-mismatched interfaces, such as InN/GaN (0001) (11.1% mismatch), interfacial structures remain unknown. Here, we investigate the atomic structure of the InN/GaN interface using atomic-resolution transmission electron microscopy and large-scale density-functional calculations. Our findings show that an interface structure without any misfit dislocations is formed, where an InN single monolayer at the interface accommodates the entire misfit. We argue that the mechanism underlying the formation of this interface monolayer is the flexibility of the group III–nitrogen bond network.
Unveiling the face-dependent ice growth kinetics: Insights from molecular dynamics on the basal and prism surfaces
Authors: Shi Jihong , Fulford Maxwell , Salvalaglio Matteo , Molteni Carla
Published: February 2025

Ice nucleation and growth are critical in many fields, including atmospheric science, cryobiology, and aviation. However, understanding the detailed mechanisms of ice crystal growth remains challenging. In this work, crystallization at the ice/quasi-liquid layer (QLL) interface of the basal and primary prism (prism1) surfaces of hexagonal ice (Ih) was investigated using molecular dynamics simulations across a wide range of temperatures for the TIP4P/Ice model, with comparisons to the mW coarse-grained model. Together with elucidating the temperature-dependent mechanisms of crystallization, face-specific growth rates were systematically estimated. While the prism surface generally exhibits faster growth rates than the basal surface, a temperature-dependent crossover in growth rates between the basal and prism surfaces is observed in TIP4P/Ice simulations, which correlates with crossovers in QLL thickness and properties and with the well-known column to platelets transition in ice-crystal habits at low vapor pressure. This observation helps decode the complex dependence between crystal morphology and temperature in ice crystals.