bluuebunny/crossref_metadata_2025 huggingface dataset:
Permittivity of solid and liquid deuterium. Increase in polarizability during crystallization
Authors: Udovidchenko B. G. , Esel’son V. B.
Published: January 2025

The permittivity of the condensed phase of n-D2 has been measured as a function of pressure and temperature. Measurements were carried out under pressures up to 70 kg/cm2 and covered the melting line. An increase in the polarizability of deuterium was observed as a result of crystallization. It is shown that its mechanism involves the influence of the crystalline field on the internal degrees of freedom of molecules. The effect of such a mechanism on the pressure dependence is discussed in different phases of hydrogen in other substance with a dispersive interaction.
Electronic structure of films of the La–Ba–Cu–O system
Authors: Dubrovskii O. I. , Kurganskii S. I. , Domashevskaya É. P.
Published: January 2025

The electronic structure of La2CuO4 and LaBaCuO4 films is investigated by using the linearized augmented plane wave method. The local partial densities of state are calculated for each atom in a unit cell. The values of density of states for the La2CuO4 film are on the whole in good agreement with the values for the bulk La2CuO4. The substitution of a Ba atom for a La atom lowers the Fermi level, while partial densities of states mainly change for the oxygen atom lying in the copper plane.
Spin waves in spin-oriented gases
Authors: Orlenko E. V. , Rumyantsev A. A.
Published: January 2025

A theory of spontaneous spin orientation of nuclei in gases at low temperatures is proposed. The effect is based on the nuclear exchange interaction whose energy is consistently calculated. The dispersion dependence for spin waves propagating in gases is considered. It is shown that these waves can be observed while using resonances in microwave technique.
On temperature dependence of soft mode frequency for low temperature phase transitions
Authors: Shchedrina N. V. , Shchedrin M. I.
Published: January 2025

The expressions for the gap in the spectrum of the soft mode responsible for the structural phase transition are obtained for the low-temperature region. It is shown that, unlike the high-temperature asymptotic form where the temperature dependence of the gap is normally linear, in the case under consideration it depends significantly both on the dynamics of the soft mode and on the anisotropy of its spectrum. A model in which the temperature dependence of the gap is determined by the intrinsic anharmonism of the soft mode is analyzed. Purely vibrational and overdamped dynamics of the soft mode for an isotropic spectrum and anisotropic spectrum typical of axial ferroelectrics are considered. The obtained results can be applied for structural phase transitions accompanying the superconducting transition in ceramics as well as for transition in A4B6-type compounds in which the transition temperature is lower than the Debye temperature.
Stabilization of hydrogen and deuterium atoms in argon and neon matrices
Authors: Dmitriev Yu. A. , Zhitnikov R. A. , Kaimakov M. E.
Published: January 2025

Improved experimental technique has been used to stabilized hydrogen and deuterium atoms in solid Ar and Ne matrices. It is found that H and D atoms are stabilized in these matrices at two nonequivalent trapping sites. For H and D atoms in solid argon, the narrowest experimentally recorded EPR spectral lines having a width ΔH = 55 (15) mG have been observed during matrix isolation of particles. The isotope effect has been detected in the matrix shifts of hyperfine structure constants of stabilized atoms.
Spatially inhomogeneous states in orientationally ordered cryocrystals
Authors: Belotserkovskii V. V. , Strzhemechnyi M. A.
Published: January 2025

Spatially inhomogeneous states of orientational order parameter of molecular cryocrystals due to topological factors (dislocations, boundary, etc.) are considered. It is shown that the width of such states is of the order of atomic spacing. The orientations in the domain wall and the boundary layer, as well as the surface energy of domain walls of various types are calculated numerically.
Observation of Josephson effect on TIBaCaCuO–TIBaCaCuO junctions
Authors: Akimov A. I. , Boiko B. B. , Borovitskii S. I. , Gatal’skaya V. I. , Gelikonova V. D. , Dem’yanov S. E. , Klushin A. M. , Kurochkin L. A. , Stribuk E. K.
Published: January 2025

The results of investigation of Josephson junctions of thallium ceramics at temperatures 78−102 K are reported.
Superconducting phase α
t-(BEDF-TTF)2l3 and its formation
Authors: Kozlov M. É. , Baran N. P. , Pokhodnya K. I.
Published: January 2025

EPR and polarized reflection spectra of the crystals of superconducting (Tc = 7 K) αt-phase of (BEDT-TTF)2I3 are investigated in the range 25000–400 cm−1. It is shown that its properties are similar to those of the superconducting β-modification of this compound (Tc = 1.5 K), except for the broadening of the EPR line observed at T < 50 K. This broadening is caused by the twins in αt-crystals which are apparently responsible for the stabilization of the state with Tc = 7 K.
Heat capacity of intermetallic compounds GdZn–GdCu
Authors: Kourov N. I. , Tsiovkin Yu. N.
Published: January 2025

The heat capacity of the intermetallic compounds GdZnxCu1–x has been measured in the temperature range 3–300 K. It is shown that in the region of the concentration phase transition of ferromagnet (x = 1) — antiferromagnet (x = 0) type, the Debye temperature and the electron component of the heat capacity have a minimum at x ≈ 0.45. A large value γ ∼ 70 mJ/mol · K2 has been observed for samples with x < 0.8 and is associated with the hybridization of the excited 4f-states of Gd3 ions with conduction band states. The phase diagram of the magnetic states of the system with a bicritical point near xc ≈ 0.5 is constructed.
EPR observation of stimulated ortho–para conversion in solid H2 and D2
Authors: Zhitnikov R. A. , Dmitriev Yu. A. , Kaimakov M. E.
Published: January 2025

The EPR method is used to detect and investigate the process of ortho–para conversion in molecules of solid H2 and D2, which is stimulated by nitrogen atoms stabilized in these molecular matrices.
Anisotropy of conduction electron g-factors in molybdenum and tungsten
Authors: Savchenko N. V. , Grechnev G. E.
Published: January 2025

A theoretical analysis of conduction electron g-factors in bcc transition metals molybdenum and tungsten is carried out. A considerable anisotropy of g-factors is established for these metals in various sheets of the Fermi surface as well as for extremal orbits on separate sheets.
Absorption of electromagnetic waves in Y- and La-based HTS metaloxides
Authors: Eremenko V. V. , Zherebchevskii D. É. , Moiseeva T. N. , Chabanenko V. V.
Published: January 2025

The effect of an external rf and a constant magnetic field on the temperature dependence of the surface impedance of metaloxide ceramic plates based on Y- and lanthanoids has been studied experimentally in the frequency range 103−107 Hz. The peak observed in the temperature dependence of impedance is attributed to the size effect when the skin-depth δ becomes comparable with the half-thickness of the sample. A contactless method is proposed for a quick quality control of the ceramic samples and for determining the critical temperature.
Thermodynamical fluctuations near the electron topological transition point
Authors: Golosov D. I. , Rzhevskii V. V.
Published: January 2025

Thermodynamical fluctuations of electron compressibility, electron specific heat and temperature pressure coefficient (1/T) (∂P/∂T) near I. M. Lifshits’ electron-topological transition (ETT), or the 2 1/2 order phase transtion point, are investigated. It is shown that at sufficiently low temperature in a pure metal the fluctuations increase sharply due to the proximity of the ETT point. The temperature dependence of fluctuations differs qualitatively from the usual one. The effect of impurities on fluctuations near the ETT point is also discussed.
Variation of flow stress during superconducting transition in aged lead–antimony alloys
Authors: Isaev N. V. , Fomenko V. S. , Pustovalov V. V.
Published: January 2025

The jump in the flow stress during the superconducting transition is measured in the absence (Δτsn , B0 = 0) and presence (Δτsn) of a trapped magnetic flux in Pb-Sb alloys subjected to aging in order to change their defect structure. The samples were deformed by stretching at a constant rate 7·10−5 s−1 at T = 4.2 K, and their state was varied with the help of the magnetic field produced by a superconducting solenoid. The dependences of the quantities B0, Δτsn and Δτ′sn on aging time are obtained. It is shown that Δτsn does not change with aging, while the concentration dependences Δτsn (c) and Δτ′sn (c) are considerably different. A correlation is established between the effective stresses and the quantity Δτsn.
Diagnostics of superconductivity in La–Ba–Cu–O from luminescence spectra: comparison of optical and magnetic measurements
Authors: Panfilov A. S. , Rybalko Yu. I. , Samovarov V. N. , Svechkarev I. V. , Smirnov A. I. , Fugol’ I. Ya.
Published: January 2025

Comparative measurements of emission spectra, magnetic susceptibility and resistive characteristics of La–Ba–Cu–O samples are made in the temperature interval between 6 and 140 K. It is shown that the narrow impurity emission line at 3.36 eV is sensitive to phase-transition points including the superconducting phase onset. Impurity emission spectra may serve as local optical probes for detecting electron and lattice changes in high-temperature superconductors.
Pressure dependence of magnetic susceptibility of metals
Authors: Svechkarev I. V.
Published: January 2025

A brief survey of works on the effect of pressure on the magnetic susceptibility due to the sp-, d-, and f-type electron states is presented. The data on the atomic volume of the parameters characterizing the band spectrum and electron interaction are considered. The behavior of the exchange-correlation enhancement of spin paramagnetism in transition metals is shown to differ considerably from the theoretical prediction based on the local approximation of the spin density functional. A possible reason behind the pressure dependence of the paramagnetic moment of stable f-states in heavy rare-earth metals is analyzed.
Three-line NMR spectra of 57Fe nuclei in domain boundaries of BaFe12O19
Authors: Bezlepkin A. A. , Kuntsevich S. P. , Popkov Yu. A.
Published: January 2025

NMR spectra of 57Fe nuclei in barium hexaferrite are measured by using steady-state and pulse techniques in the temperature range from 4.2 to 295 K. A three-line spectrum consisting of one line from the nuclei localized at the edge of a domain boundary (DB) and two lines from the nuclei centered at DB was recorded for nuclei in the 12k sites (sublattice a) with the point symmetry m in DB. A strong anisotropy (11.8 kOe at 77K) was observed in the local fields in the one-domain state of the ferrite for the nuclei at the 12k sites with a change in the magnetic moment orientation in the basal plane. An analysis of the obtained experimental results reveals that the local field anisotropy is due to the anisotropy in dipole fields. It is shown that the three-line NMR spectrum of the nuclei in the sublattice a in DB is related to a specific dependence of local fields in these nuclei on two angular variables specifying the orientation of the local magnetization.
Two-dimensional elemental analysis of a superconductor surface by secondary-ion mass spectroscopy
Authors: Chenakin S. P. , Cherepin V. T. , Nikitin B. G. , Klimenko G. A. , Rüdenauer F. G. , Steiger W.
Published: January 2025

Secondary ion images of the surface of superconducting ceramics YBa2Cu3O9–x are obtained for Y, Ba, and Cu ions with a spatial resolution of about 15 μm, and the linear distribution of emission currents along chosen directions is presented. An interpretation is offered for the secondary ion images and linear current distribution. The contribution of the ceramic surface microtopography and concentration inhomogeneities in the component distribution to the ion image contrast is determined.
Conductivity of Ni–Cr–Fe alloys at 4.2–100 K and the influence of quantum interference effects and magnetic state on it
Authors: Pecherskaya V. I. , Butenko A. V. , Bol’shutkin D. N.
Published: January 2025

Temperature dependences of resistivity and magnetic susceptibility of highly resistive Ni–Cr–Fe alloys are investigated at 4.2–293 K. Resistivity minima are observed in the low-temperature region along with a decrease in magnetic susceptibility due to the transition to the spin glass state. The influence of the change in the magnetic state and of quantum interference effects of conduction electrons (including the electron–electron, electron–phonon and electron-magnon interactions) on resistivity is analyzed.
Metallic glasses as nonsaturated ferromagnets
Authors: Akhiezer I. A. , Belozorov D. P.
Published: January 2025

The decrease in spontaneous magnetization per atom during the amorphization of 3d-ferromagnets is explained by proceeding from the concept of ferromagnetic metallic glasses as nonsaturated ferromagnets. The spontaneous magnetization and longitudinal magnetic susceptibility are determined at T = 0, and the temperature dependence of spontaneous magnetization at low temperatures is analyzed. The experimentally observed discrepancy between the spin wave rigidity and the coefficient in Bloch’s 3/2-law is explained.
Ground state structure of a spin chain with a Dzyaloshinskii-type interaction
Authors: Zvyagin A. A.
Published: January 2025

The ground-state energy of a uniaxial spin chain with a Dzyaloshinskii-type interaction is estimated. The transverse spin structure of the ground state of the system is analyzed.
Effect of uniaxial pressure on the superconducting transition temperature in niobium diselenide
Authors: Obolenskii M. A. , Chashka Kh. B. , Beletskii V. I. , Gvozdikov V. M.
Published: January 2025

The behavior of the superconducting transition temperature in NbSe2 and Nb0.9Sn0.1Se2 is studied experimentally under a uniaxial pressure perpendicular to the plane of the layers. The Tc(P) dependence is shown to be nonmonotonic in the region of low pressures. A qualitative explanation of the observed effect is proposed.
A possible role of condensed oxygen in internal friction of high-T
c metal-oxide superconductors
Authors: Leont’eva A. V. , Marinin G. A. , Svistunov V. M. , Sukharevskii B. Ya.
Published: January 2025

It is shown that internal friction anomalies at different frequencies in the samples of La-Sr and Y-Ba metal-oxide high-Tc superconductors at temperatures near 24, 44, 55 and 90 K can be due to phase transitions in condensed oxygen.
The role of the energy gap in non-Josephson generation
Authors: Churilov G. E. , Dikin D. A. , Dmitriev V. M. , Svetlov V. N.
Published: January 2025

Dependences of generation frequency and current of non-Josephson oscillations in superconducting films on the parameters determining the energy gap (temperature and magnetic field) are investigated experimentally. The obtained results are analyzed by using the model proposed earlier.
Transition to resonating valence bond state in a high-frequency electromagnetic field
Authors: Livdan D. O. , Tokar’ O. I. , Fil’ D. V.
Published: January 2025

The effect of high-frequency electromagnetic radiation on the parameters of transition into the resonating valence bond state in a two-dimensional system with a strong local electron repulsion is considered. Corrections to the gap in the spinon spectrum associated with various mechanisms of influence of the field on elementary scattering acts are calculated. It is shown that on account of high temperatures of phase transitions, electron–phonon collisions play a dominant role in the variation of characteristic parameters under the action of the field. The stochastization due to phonons may result in an increase as well as a decrease in the phase transition temperature. Conditions for stimulation (suppression) of a transition by the electromagnetic field are formulated.
Carrier localization and superconductivity in YBa2Cu3O7–δ single crystals
Authors: Obolenskii M. A. , Bondarenko A. V. , Zubareva M. O.
Published: January 2025

Temperature dependences of the electrical resistivity along the c-axis and in the basal plane of YBaCuO single crystals with different degrees of perfection and different oxygen contents are investigated. It is shown that depending on the oxygen content, the conductivity along the c-axis can vary from metallic type to jump-type.
Low-temperature phase transitions in magnetically ordered neodymium
Authors: Bulatov A. S. , Dolzhenko V. F.
Published: January 2025

Single-crystal neodymium samples are investigated by using X-ray diffraction technique in the temperature interval between 4.2 and 300 K. The results provide new information on the temperature dependence of the lattice parameters a and c of a double hexagonal closely packed structure and about linear thermal expansion coefficients α⊥ and α∥. The observed anomalies on these temperature dependences at TN1 = 20 K, TN2 = 7.8 K and T0 = 6.5 ± 0.2 K are due to antiferromagnetic ordering. It is shown that magnetic transformations at TN1 and TN2 are second-order phase transitions, while a first-order phase transition occurs at T0. Neodymium exhibits sharp anomaly in thermal expansion in the paramagnetic region 20–50 K due to the splitting of the 4f-levels by the crystal field (Schottky anomaly).
Alternating current Josephson effect in TI2Ca2Ba2Cu3O10+x
Authors: Aminov B. A. , Akimov A. I. , Brandt N. B. , Thuy Nguen Min , Sudakova M. V. , Pirogov Yu. A. , Ponomarev Ya. G.
Published: January 2025

The effect of external microwave field on the current-voltage characteristics (IVC) of Josephson break junctions in Tl2Ca2Ba2Cu3O10+x-based samples is investigated. Shapiro steps are observed in a wide temperature range 4.2 K ≤ T ≤ 104 K. The effective charge of superconducting electrons is estimated as q = (2 ± 0.05)e. The IVC of some junctions display well defined subharmonic steps.
Longitudinal magnetoresistance of conductors at high current densities
Authors: Peschanskii V. G. , Stepanenko D. I.
Published: January 2025

The mechanisms leading to deviations from Ohm’s law in conductors placed in a uniform constant external magnetic field H0 parallel to the direction of the current j at low temperatures are studied theoretically. The quantum and classical corrections to longitudinal conductivity are calculated for bismuth-type metals. The electric current distribution over the cross section of a metal plate of thickness d exceeding the mean free path of charge carriers is obtained under the conditions of the dynamic nonlinear effect caused by the influence of the magnetic field of current on the ballistics of conduction electrons. It is shown that by varying the value of H0, it is possible to analyze separately the dynamic nonlinear effect and the deviation from Ohm’s law due to heating of charge carriers.
Magnetization reversal of noncentral antisymmetric antiferromagnetic crystals of cobalt and iron fluorides
Authors: Bibik A. V. , Kharchenko N. F. , Petrov S. V.
Published: January 2025

Visual and magnetooptical investigations of coercion into single-domain state and magnetization reversal processes are carried out in antiferromagnetic tetragonal crystals of CoF2 and FeF2. Antiferromagnetic domain boundaries were set in motion by using the methods based on the piezomagnetic effect and quadratic magnetization. The coercivity of AFM domain walls in CoF2 is determined and the values of threshold pressure which sets a domain wall into motion are obtained.
Experimental arrangement to study the impact of atmospheric turbulence on user-defined beams
Authors: Jomy A. , Mehta S. , Jacob J. , Anirudh S. , Krishna D. K. , Kumar R. , Gondhalekar J. , Adheena C. K. , Jeevan M. , Akshay M. S. , Mohan N. , Narayanamurthy C. S. , Pathak B.
Published: January 2025

In the present work, we propose an experimental setup to investigate the effect of atmospheric turbulence on user-defined beams. The user-defined beams were formed by writing reconfigurable patterns on a spatial light modulator, allowing the impact of atmospheric turbulence to be investigated simultaneously and in real time. The programmable controllability provides several flexibilities to the system, such as the ability to create different beam types simultaneously, control the separation between different beams, compensate for aberrations, and easily switch between different beam types. The experimental results illustrate the feasibility and effectiveness of the proposed experimental setup for studying the impact of atmospheric turbulence on different beams simultaneously in laboratory settings using a pseudo-random phase plate.
Superconducting flip-chip devices using indium microspheres on Au-passivated Nb or NbN as under-bump metallization layer
Authors: Paradkar Achintya , Nicaise Paul , Dakroury Karim , Resare Fabian , Wieczorek Witlef
Published: January 2025

Superconducting flip-chip interconnects are crucial for the three-dimensional integration of superconducting circuits in sensing and quantum technology applications. We demonstrate a simplified approach for a superconducting flip-chip device using commercially available indium microspheres and an in-house-built transfer stage for bonding two chips patterned with superconducting thin films. We use a gold-passivated niobium or niobium nitride layer as an under-bump metallization (UBM) layer between an aluminum-based superconducting wiring layer and the indium interconnect. At millikelvin temperatures, our flip-chip assembly can transport a supercurrent with tens of milliamperes, limited by the smallest geometric feature size and critical current density of the UBM layer and not by the indium interconnect. We show that the pressed indium interconnect itself can carry a supercurrent exceeding 1 A due to its large size of about 500 μm diameter. Our flip-chip assembly does require neither electroplating nor patterning of indium. The assembly process does not need a flip-chip bonder and can be realized with a transfer stage using a top chip with transparency or through-vias for alignment. These flip-chip devices can be utilized in applications that require few superconducting interconnects carrying large currents at millikelvin temperatures.
Doping-induced enhancement of Curie temperature in Zn2Ru1−xAxMn (A = Ti, Mn, Co, Zr, and Rh) Heusler alloys: An ab initio investigation
Authors: Karunakaran M. , Banerjee Rudra
Published: January 2025

This study examines the structural stability, electronic, and magnetic properties of off-stoichiometric Zn2Ru1−xAxMn Heusler alloys (with, A = Ti, Mn, Co, Zr, and Rh) using first-principles calculations. We find that the L21 phase is more stable than the XA phase across both ordered and disordered configurations. The variations in lattice parameters with off-stoichiometry are attributed to the atomic radii of the dopants. Our results indicate that Zn2Ru1−xAxMn alloys exhibit ferromagnetic metallic behavior, driven primarily by Mn-Mn, Ru-Mn, and A-Mn exchange interactions. These interactions are further analyzed to calculate the Curie temperature using the mean-field approximation. The Curie temperature for Zn2RuMn is found to be approximately 300 K, which increases to 428 K upon Co doping. Our findings suggest that doping provides a means to control the Curie temperature, offering substantial potential for applications in room-temperature magnetocaloric materials and shape memory alloys. This tunability enhances the functional versatility of these alloys, making them promising candidates for future technological applications.
Parallel manipulation of multiple ink droplets via near-infrared light on lubricant infused surface
Authors: Hu Yalin , Wu Jie , Luo Haiyan , Su Guanqi , Meng Xiangxi , Liu Liyu , Chen Guo
Published: January 2025

Previous studies on light-driven droplet transport often use light to heat the substrate to generate a temperature difference, thereby changing the wettability or surface tension at two ends of a droplet, to propel the droplet forward, and not much attention has been paid to the droplets with photothermal properties. Herein, we introduce a method of ink droplet manipulation via near infrared light-driven on lubricant infused surfaces. Rather than heating the substrate itself, this method uses near-infrared light to irradiate one end of an ink droplet, creating a temperature gradient inside it and forming a Marangoni flow that pushes the droplet forward. It is demonstrated that the ink droplets would experience two stages during sliding, and the movement ability of the ink droplets depends on their absorbance and size; specifically, the average acceleration and steady velocity of the droplets are both positively correlated with their absorbance and negatively correlated with their volume. The work not only proves that the method can realize conventional individual droplet manipulation such as controllable transport along arbitrary paths, but also proposes a unique customized transport and merging strategy for multiple ink droplets. This investigation offers a simple and versatile manipulation approach for ink droplets, and the relevant results have potential applications in the fields of precise maneuver of light-driven droplets and droplet-based inkjet printing.
Spin transfer torque switching in double magnetic tunnel junctions based on dual MgO layers
Authors: Mihajlović G. , Jung W. , Chopdekar R. V. , Lille J. , Grobis M. K.
Published: January 2025

We report fabrication and characterization of double magnetic tunnel junction (DMTJ) magneto-resistive random access memory cells that exhibit characteristic about 2X reduction of switching current compared to single reference layer junctions, but maintain high tunneling magnetoresistance ratio exceeding 120 %, high coercive fields of the free layer of more than 2 kOe for 65 nm cells, and magnetically stable reference layers with pinning fields above 6 kOe. Switching analysis performed for two different relative magnetization orientations of the reference layers shows that the net switching current is the result of combined spin transfer torque effects of the individual reference layers, with tunneling and spin-valve-like contributions adding constructively. Our work shows that efficient reduction of switching current can be achieved in double magnetic tunnel junctions with dual MgO layers where one of the layers has significantly lower resistance-area product to enable high magnetoresistance ratio.
Design of miniaturized and polarization insensitive frequency selective surface filter with large band ratio
Authors: Li Yi , Xu Ruize , Ren Peng , Xu Baoyi , Wang Minrui , Chen Chen , Chen Keqing , Xiang Zheng
Published: January 2025

In this paper, a miniaturized and polarization insensitive frequency selective surface filter with large band ratio (BR) is presented. This structure consists of one metal layer and two dielectric layers. The metal layer includes two parts, with the outer square loop providing a lower frequency stopband and the inner pattern providing a higher frequency stopband. The structure has excellent miniaturization characteristics, in particular, the unit size is only 0.054λ0 and the thickness is only 0.014λ0, where λ0 is the wavelength corresponding to the first resonant frequency. Additionally, there is only one layer of metal layer, which greatly reduces the processing complexity and cost. The measurement results show that for TE and TM polarization, the center frequencies of the two stop bands are 2.03 and 18.98 GHz corresponding to a BR of 9.35. It can be used as a spatial dual frequency filter with large frequency band separation. In addition, the proposed structure also possesses advantages such as wideband response, polarization insensitivity, and high angle stability. The simulation results are in good agreement with the measured results.
Thermal conductivity of AlN thin films deposited by reactive DC magnetron sputtering on different substrates using ultra-fast transient hot strip technique
Authors: Zernadji R. , Belkerk B. E. , Riah B. , Ayad A. , Rammal M. , Camus J. , Garnier B. , Djouadi M. A.
Published: January 2025

In the frame of this work, we report a profound insight into the thermal conductivity (k) of aluminum nitride (AlN) thin films deposited on AlN-molecular beam epitaxy (MBE)/Si(111) and AlN-Kyma/Si(111) substrates at low temperatures (<200 °C) using reactive direct current magnetron sputtering (DCMS). Our concern is not on the thermal properties at the nanoscale, but rather on relating thermal macroscopic properties to the microstructure for submicronic to micronic AlN films. As the mean free path for AlN material is about 100 nm, the thickness of our films lies between 400 nm and 2 μm. The k measurements were conducted using the ultra-fast transient hot strip technique. It was found that the k values of the deposited films change depending on both the substrate type and the film thickness. For the 500 nm AlN thick film, k value was about 250 W m−1 K−1 for AlN-DCMS films grown on 10 nm AlN-MBE/Si against 90 W m−1 K−1 for those deposited on 200 nm AlN-Kyma/Si. The thermal boundary resistance has been computed equal to (0.25 ± 0.08) × 10−9 K m2 W−1 on 10 nm AlN-MBE/Si against (3.56 ± 1.50) × 10−9 K m2 W−1 on 200 nm AlN-Kyma/Si. Additionally, both pole figures and high resolution transmission electron microscopy confirm k results. In fact, pole figures confirm the good crystal quality of the film on both substrates, but HR-TEM analyses show that the AlN films grown on 10 nm AlN-MBE/Si template exhibit good crystalline quality with an epitaxial regrowth and abrupt interface compared to those obtained for 200 nm AlN-Kyma/Si. It also appears that the thermal boundary resistance plays a major role in the thermal properties of AlN films.
Boosting thermoelectric properties of n-type PbS across a broad temperature range through doping with trace amounts of InBi
Authors: Hou Zhenghao , Cui Qiujuan , Cui Jiaomin , Song Shuang , Hong Tao , Wang Shu-Fang , Qian Xin
Published: January 2025

Lead sulfide (PbS) is a promising thermoelectric material due to its high availability, thermal stability, and cost-efficiency, with research predominantly aiming to enhance its carrier concentration through heavy doping for optimal ZT values at high temperatures. However, this approach often results in suboptimal performance at ambient temperature, significantly constraining its applicability in thermoelectric cooling technologies. In this work, the carrier concentration of n-type PbS is optimized by incorporating trace amounts of InBi. Due to the low carrier concentration, PbS retains a high Seebeck coefficient and carrier mobility, resulting in a high average power factor (PFave) of 15.4 μW·cm−1·K−2 within the temperature range from 300 to 773 K. In addition, the introduction of In/Bi interstitial atoms and dislocation defects enhances phonon scattering, effectively reducing the lattice thermal conductivity of PbS. The peak ZT value of Pb0.999(InBi)0.001S at 773 K reaches ∼1.0, while an average ZT value (ZTave) of ∼0.6 is achieved between 300 and 773 K in Pb0.9995(InBi)0.0005S. This study demonstrates that trace element doping is an effective strategy for optimizing the thermoelectric performance of PbS across a wide temperature range, which is vital in the thermoelectric power generation and refrigeration application.
Sliding ferroelectricity influenced by charge doping in bilayer antiferromagnetic H–ScO2
Authors: Zhu Jiajun , Zhao Heyun , Hu Wanbiao
Published: January 2025

Sliding ferroelectricity has been extensively studied as it provides an approach to designing van der Waals ferroelectric materials with nonpolar components. In this work, we demonstrate the sliding ferroelectricity of bilayer H–ScO2, which is formed by an interlayer antiferromagnetic configuration of monolayer H–ScO2 ferromagnetic material. The out-of-plane polarization results from charge transfer between the layers, causing an unequal charge distribution within them and yielding a polarization value of ±1.26 pC/m. We found that increasing the doping concentration suppresses the polarization value. This phenomenon results from the differing occupancy ratios of electrons and holes in the conduction and valence bands after introducing electron or hole doping into the system. The closer the number of electrons in the conduction band is to that in the valence band, the more pronounced the suppression of polarization. Our work offers a perspective for the design of advanced van der Waals ferroelectric materials.
Exercise intensity and training alter the innate immune cell type and chromosomal origins of circulating cell-free DNA in humans
Authors: Rodrigues Kameron B. , Weng Ziming , Graham Zachary A. , Lavin Kaleen , McAdam Jeremy , Tuggle S. Craig , Peoples Brandon , Seay Regina , Yang Sufen , Bamman Marcas M. , Broderick Timothy J. , Montgomery Stephen B.
Published: January 2025

Exercising regularly promotes health, but these benefits are complicated by acute inflammation induced by exercise. A potential source of inflammation is cell-free DNA (cfDNA), yet the cellular origins, molecular causes, and immune system interactions of exercise-induced cfDNA are unclear. To study these, 10 healthy individuals were randomized to a 12-wk exercise program of either high-intensity tactical training (HITT) or traditional moderate-intensity training (TRAD). Blood plasma was collected pre- and postexercise at weeks 0 and 12 and after 4 wk of detraining upon program completion. Whole-genome enzymatic methylation sequencing (EM-seq) with cell-type proportion deconvolution was applied to cfDNA obtained from the 50 plasma samples and paired to concentration measurements for 90 circulating cytokines. Acute exercise increased the release of cfDNA from neutrophils, dendritic cells (DCs), and macrophages proportional to exercise intensity. Exercise training reduced cfDNA released in HITT participants but not TRAD and from DCs and macrophages but not neutrophils. For most participants, training lowered mitochondrial cfDNA at rest, even after detraining. Using a sequencing analysis approach we developed, we concluded that rapid ETosis, a process of cell death where cells release DNA extracellular traps, was the likely source of cfDNA, demonstrated by enrichment of nuclear DNA. Further, several cytokines were induced by acute exercise, such as IL-6, IL-10, and IL-16, and training attenuated the induction of only IL-6 and IL-17F. Cytokine levels were not associated with cfDNA induction, suggesting that these cytokines are not the main cause of exercise-induced cfDNA. Overall, exercise intensity and training modulated cfDNA release and cytokine responses, contributing to the anti-inflammatory effects of regular exercise.
Phonetic realization of the Emphasis contrast in voiceless stops by speakers of four Arabic
varieties
Authors: Kulikov Vladimir , Hazi Reem
Published: January 2025

This paper investigates the role of F2 and VOT in realization of the contrast in emphasis among speakers of Arabic
varieties of the Levant (Lebanese, Syrian) and the Gulf (Saudi, Qatari). The results show that the two dialect groups
systematically differ in acoustic realization of plain and emphatic voiceless stops. While Lebanese and Syrian varieties reveal
the traditional pattern, in which the contrast is predominantly realized as a difference in F2 (Plain: 1808 Hz, Emphatic:
1097 Hz), Qatari and Saudi ones demonstrate a pattern with VOT as the main acoustic correlate. Plain [t] is produced with
aspiration (M = 72 ms), and emphatic [tʕ] is unaspirated (M = 17 ms). The difference
in F2 in the Gulf speech is, in contrast, smaller: low vowel [aː] is back in both contexts, with more retraction in the emphatic
context (Plain: 1230 Hz; Emphatic: 1108 Hz).
touch in language
Authors: Caballero Rosario , Paradis Carita
Published: January 2025

This study reviews the literature on touch to establish an analytical framework for the study of
touch in communication through language. Two questions are at the heart of the study — an ontological and a
methodological one: What counts as touch, and how can we investigate the way we talk about touch? Within the
broad framework of cognitive semantics, we offer a general approach to touch and identify two main types of Gestalt
profiles related to the dynamicity in the Gestalt formation, namely activity and experience, in which case the former is related
to external stimulation only, while the latter may be the result of external or internal stimulation.
A compact in-situ polarized 3He system for neutron scattering
Authors: Tang Jian , Wang Bin , Huang Chuyi , Gao Han , Zheng Qingbo , Liu Renhong , Ye Fan , Qin Zecong , Wang Tianhao , Salman Ahmed , Dong Yuchen , Tian Long , Deng Changdong , Li Jun , Liu Lei , Qi Xin , Zhang Junpei , Tong Xin
Published: January 2025

The performance of a new compact (55 cm × 56 cm × 48 cm) in-situ spin-exchange optical pumping (SEOP) 3He-neutron spin filter (NSF) system developed at the China Spallation Neutron Source (CSNS) is presented. The enclosed NSF cell, filled with 2.53 bar 3He, was born with a 3He polarization of around 60%. After subsequent improvements to the magnetic field and heating system, this in-situ system is able to achieve 75.66%±0.09% 3He polarization, resulting in a 96.30% neutron polarization at 2 Å. This highly compact in-situ system is equipped with self-supportive features, pre-pumping capabilities, polarization maintenance, and low-noise Nuclear Magnetic Resonance (NMR) system. These advantages significantly reduce the preparation time and simplify the processes in polarized neutron experiments, allowing it to be adopted on various neutron beamlines in China, especially those with limited sample space. These characteristics establish it as a quasi-standardized system, playing a vital role in polarized neutron experiments including polarized neutron imaging, neutron reflection, the performance calibration of polarized neutron instruments, Neutron Optics Parity and Time Reversal EXperiment (NOPTREX).
Electromagnetic energy associated with magnetic vortices in superconductor/paramagnet heterostructures
Authors: Genenko Yuri , Rauh Hermann
Published: January 2025

Redistribution of the transport current in a superconductor affected by paramagnetic shields provides a possibility of strongly overcritical states and a drastic reduction of AC losses in thin superconductor films and tubes. Such superconductors subject to para- or diamagnetic shielding are studied by means of the potential theory and the critical state model when carrying a transport current or exposed to an external magnetic field. Analytical results are obtained for a number of shielding geometries and confirmed by numerical solutions. It is shown that using magnetostatic-electrostatic analogies allows consideration of paramagnetic shielding configurations of arbitrary shapes and magnetic permeabilities by means of common finite-element solvers to enhance the dissipation-free transport currents in superconductors and reduce AC losses in them. Furthermore, using the generalized London theory, the penetration of magnetic flux into magnetically shielded bulk superconductors is studied and the enhancement of the Bean-Livingston barrier is established.
We-experiences
Authors: Zahavi Dan
Published: January 2025

Social reality contains many different types of social formations. Some involve emotional contagion, others involve we-experiences and the adoption of a strong we-perspective. But what does it mean for individuals to come together as a we? This chapter considers a proposal that can be found in the work of Gerda Walther. Walther distinguishes between we-experiences that involve direct social interaction and the co-presence of the participants, and group-based experiences that one can have even when others are absent. In both cases, however, constituting a we together with others isn’t merely a question of possessing certain common objective properties, nor is it enough to be in the same kind of intentional state and be directed at the same kind of object. Rather, for Walther, constituting a we together with others involves processes of identification that transform the very ownership of the experiences.
Basic Selfhood
Authors: Zahavi Dan
Published: January 2025

There has been, and continues to be, much controversy about the nature and structure of both self-consciousness and selfhood. But even a cursory look at the ongoing discussions should make it clear that distinctions are needed since there are not only different types of self-consciousness but also different dimensions of selfhood. Departing from an analysis of the subjective or first-personal character of phenomenal consciousness, this chapter defends the existence of pre-reflective self-consciousness, introduces the notion of a minimal experiential self, replies to a variety of objections that have been raised against this view, and argues that the notion in question is indispensable for a proper understanding of the we.
Dyads and Triads
Authors: Zahavi Dan
Published: January 2025

You can constitute a we together with your partner, your family, your friends, your professional group, your local community, and your national community. But these are different kinds of we, and some of them affect our self-identity in much stronger ways than others. The chapter first discusses different types of dyadic we-relationships, including romantic partnerships, and then expands the scope by considering what happens the moment a dyad becomes a triad. Drawing on the works of Simmel, Berger and Luckmann, and Sartre, it is argued that the addition of a third transforms the we-relationship. A triad does not only have a different level of complexity than a dyad, it also has more entitativity, and if we are to understand the constitution of a superindividual we, one that can survive membership change, the analysis of the triad offers important clues.
Graves
Authors: King Laura
Published: January 2025

This chapter explores the meanings of graves and other sites of human remains, such as scattered ashes, in the process of connecting with and remembering the dead. It examines a few individual stories in depth, such as Jean Barker, who lost access to her parents’ grave, and Bill Rollinson, who tried to find the grave of his baby sister who died before he was born. It argues that choice and control were crucial to these families in the use of graves and other sites, and that such places not only formed sites of memory for the individuals buried there, but also a means to connect to ideas of family history and heritage.
Researching
Authors: King Laura
Published: January 2025

This book is based on the research of fifteen family historians: this chapter takes that research process itself as a subject, analysing the ways in which family history has become an increasingly popular way to form connections with the dead and the past. Whether a relative or ancestor was known personally or not, family historians found the research process often emotional and meaningful, which helped them to pay tribute to deceased family members. This chapter explores why family history has been meaningful—or not—and the shapes it has taken over the past century. It suggests research offered a lot when there were few other traces of the past, and that family history might have changed in its methodologies, but shows a lot of continuity of past practices of recording family life.
How to Think about Politics
Authors: Allen Peter
Published: January 2025

It can be easy to feel overwhelmed by politics. It is a huge subject, leaving its imprint on every aspect of the world and people’s lives. It is also the most fitful political situation that most people can remember. Norms are shattering, assumptions long taken for granted have been undermined, and events are moving so fast that it is hard to keep on top of it all. At a time when it feels that people really need to grasp what is going on, it is getting progressively harder to do so. But what if everyone already has the ability to make sense of politics? What if it is possible to look past the mess of names and opinion polls and statistics and instead focus on the fundamentals of politics that are rooted in everyone’s daily lives? Instead of trying to keep up, this book advises people to pause and step back. Think bigger. Think deeper. Rather than repeatedly getting caught in the swirl of day-to-day politics, what if it was possible to cultivate a set of tools and perspectives with which to interpret what is going on? By exploring five key political ideas—power, knowledge, presence, possibility, and the question of what we want—this book provides ways to think more systematically about politics, to better hold power to account, and to more clearly articulate hopes for the future.
Breathe the Air
Authors: Allen Peter
Published: January 2025

This introductory chapter motivates the book and sketches an outline of the five main chapters that follow. It begins with a discussion of the idea of ‘polycrisis’ a term used by some social scientists to describe the intersection of challenges and crises faced by advanced democracies in the twenty first century. It then introduces the fundamental political ideas that are the focus of the book — power, knowledge, representation, the question of what individuals want, and possibility. Overall, the chapter states the premise for the book: that these fundamental ideas remain useful when thinking about contemporary politics and that they are ideas that almost everybody already thinks about in their daily lives, whether they realise it or not.
Evaluation of RCV Elections
Authors: Endersby James W , Towle Michael J
Published: January 2025

This chapter analyzes the macro- or election-level effects of ranked choice voting (RCV) in recent municipal elections in the United States. These effects include topics of candidate competition, so-called wasted votes, majoritarian outcomes, and voter turnout. Building on existing knowledge reviewing a handful of cases, the election results of over 500 public officials in twenty-one cities from 2001 to 2020 allow empirical tests of these fundamental claims. Turnout tends to increase when RCV is introduced, but it declines later. Similarly, candidate competition does not increase over the long term. The concept of wasted votes or, for RCV, exhausted ballots or nontransferable votes is measured, and its incidence is dependent on several factors including the number of candidates and the rounds of counting. An empirical assessment is conducted of whether RCV elections truly produce majoritarian candidates, suggesting cases without a first-round majority winner infrequently produce majority winners among all voters.
‘Old Man Machiavelli’
Authors: Tendi Blessing-Miles
Published: January 2025

This chapter reveals the principal motives and catalyst for Zimbabwe’s 2017 coup. Zimbabwean coup-makers asserted they were wholly responsible for the preparation and execution of the coup, and they insisted the coup’s motives emanated from domestic politics. There were four main coup motives: the military generals’ disgruntlement with Mugabe’s downgrading of 1970s liberation-struggle actors and values in ZANU PF; Mugabe’s perceived weakening authority in the military, ruling party, and government; some generals’ personal ambitions in politics and the military; and insecurity in the military’s upper ranks caused by conditions of precarious job tenure and fear of criminal prosecution. Gender overlapped with some of these motives, which fortifies the argument in Chapter 2 that coups are acutely gendered operations. The chapter confirms Samuel Finer’s observation that coup motivations are often mixed, and the composite factors generally case specific. The chapter also identifies the coup’s catalyst.