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The Ca-based fluorinated MOF, named UoC-9 (UoC = University of Cologne), was previously published, crystallising in an orthorhombic crystal system with a 2nd order phase transition (Ima2 to Pna21) between room temperature and 100 K. Herein, this MOF was used as a crystalline sponge to embed a selection of six different small guest molecules inside its pores by liquid exchange. After confirming that the guest molecules were successfully loaded into the pores of UoC-9, the resulting host–guest systems were extensively analysed via single crystal X-ray diffraction. The different crystal structures allowed us to investigate the structural behaviour of UoC-9 in response to the embedded guest molecules. The lattice parameters as well as the phase transition are influenced differently by the various guests, which is described in detail by supplementary Hirshfeld surface analyses enabling us to examine the underlying host–guest interactions. The NMP@UoC-9 (NMP = N-methyl-2-pyrrolidone) system exhibits superstructure reflections with a tripled b-axis, which was also elucidated within this work. [ABSTRACT FROM AUTHOR]

Wet-chemical co-precipitation was used to create Co0.5MgxCu0.5−xFe2O4 nano-ferrites (x = 0.0, 0.2, 0.3, and 0.4). XRD, FT-IR, HRTEM, and EDX analyses were used to confirm each sample's single-phase spinel cubic crystal structure. The crystallite size was calculated from the XRD data and determined to be between (11.1570 and 16.1457 nm), with a lattice constant between (8.359 to 8.387Å). The two absorption bands found in the FTIR data were utilized to show metal cation and oxygen bond stretching at tetrahedral and octahedral positions, as well as to calculate the elastic moduli. The elemental composition and structural behavior of every sample were examined using FE-SEM and EDS. The magnetic parameters were also estimated based on the VSM data, the contribution of magnetic anisotropy (K), and the magnetic interaction by Neel's and Y-K-type magnetism modify as the Mg2+ ion substitution increases, thus we must consider how this variation in cation distribution affects all of these factors. As per the ferromagnet theory, ions originating from the magnetic tetrahedral A and octahedral B sites engage in super-exchange interactions with one another. Anti-ferromagnetic alignment occurs as a result (MB-MA). Magnetization occurs as a result. [ABSTRACT FROM AUTHOR]

The photocatalytic activity of photocatalysts can be enhanced by cation doping, and the dopant concentration plays a key role in achieving high efficiency. This study explores the impact of copper (Cu) doping at concentrations ranging from 0% to 10% on the microstructural, optical, electronic, and photocatalytic properties of zinc oxide (ZnO) nanostructures. The x-ray diffraction analysis shows a non-linear alteration in the lattice parameters with increasing the Cu content and the formation of CuO as a secondary phase at the Cu concentration of >3%. Density functional theory calculations provide insights into the change in the electronic structures of ZnO induced by Cu doping, leading to the formation of localized d electronic levels above the valence band maximum. The modulation of the electronic structure of ZnO by Cu doping facilitates the visible light absorption via O 2p → Cu 3d and Cu 3d → Zn 2p transitions. Photoluminescence spectroscopy reveals a quenching of the defect-related emission peak at approximately 570 nm for all Cu-doped ZnO nanostructures, indicating a reduction in the structural and other defects. The photocatalytic activity tests confirm that the ZnO nanostructures doped with 3% Cu exhibit the highest efficiency compared to other samples due to the suitable band-edge position and visible light absorption. [ABSTRACT FROM AUTHOR]

The paper presents a thorough investigation into the design of a Modified Core Hexa–Deca Photonic Crystal Fiber (MHD-PCF) with adjustable features to regulate dispersion and birefringence. At the target wavelength of 1550 nm, the suggested MHD-PCF exhibits extraordinary optical properties, including an ultra-high negative dispersion coefficient of − 7755 ps/(nm km) and significant birefringence of 1.905 × 10−2. The analysis entails regular changes in lattice constants and center air hole parameters, which provide insights into optical property trends. The MHD-PCF regularly exceeds existing benchmarks across a wide range of parameter adjustments. Notably, this fiber has strong nonlinearity (59.12 W−1 km−1) and low confinement loss (2.896 × 10−3 dB/cm), as well as an enhanced numerical aperture (0.5144), demonstrating its potential for efficient light coupling and supercontinuum production. These results put the Modified Core Hexa–Deca Photonic Crystal Fiber at the forefront of contemporary communication systems, and its optical enhancements and flexible features present exciting opportunities for novel Terahertz technology breakthroughs, especially in the areas of communication systems and sensing applications. [ABSTRACT FROM AUTHOR]

The strategy of partial Pb2+ substitution is applied, in prototypical MAPbI3 perovskite, with a large array of metal cations in order to comprehensively explore their possible incorporation in the perovskite lattice at Pb2+ sites and thus obtain improved photostability of the absorber. An analysis of lattice parameters and optoelectronic properties of MAPb1‐xMxI∼3 compositions allowed authors to deduce which metal cations are partially incorporated in the perovskite structure and which are expelled in the form of secondary phases. Curious effects of metal incorporation are observed, such as a decrease in the tetragonal distortion ratio and a change in the band gap. This work reveals that the doping of 11 metal cations significantly improves the photostability of the MAPbI3 films. Multiple MAPb1‐xMxI∼3 formulations deliver superior power conversion efficiencies (PCEs) in solar cells. The DFT calculations further demonstrate a complex relationship between the synthetic conditions and doping patterns. The performed study is thus a stepping stone in the development of more stable perovskite absorbers with superior photovoltaic properties. [ABSTRACT FROM AUTHOR]

The location of the H atoms in Ti, Zr, and Hf is crucial to the formation of the hydrides in these metals as it influences the crystal lattice transformation and the hydrogen diffusion involved in the hydride formation process. Although Ti, Zr, and Hf are all of hexagonal close-packed structure with similar lattice parameters, the solute H atom occupies the octahedral interstice in Ti but the tetragonal interstice in Zr and Hf, of which the origin is still mysterious. In the present work, the origin of the distinct site occupation behavior of H atom in Ti and Zr/Hf is investigated through first principles calculations. The calculated solution energies confirm that H prefers the octahedral interstice in Ti but the tetrahedral interstice in Zr and Hf. We ascribe the distinct site occupations of H in Ti and Zr/Hf to the varying Coulomb repulsion between the H (as a screened proton in the metals) and the matrix atoms against the interstitial size. The competition between the H-induced electron accumulation effect and the matrix atom debonding effect might matter as well. We propose that, as a general rule, a H atom prefers the site with a trade-off between a large space and a high electron density in metals. • Hydrogen occupies octahedral interstice in Ti but tetrahedral interstice in Zr/Hf. • H-metal atom Coulomb repulsion is responsible for the distinct site occupation of H. • H-induced electron redistribution might matter to the distinct site occupation of H. • H prefers the site with a trade-off between large space and high electron density. [ABSTRACT FROM AUTHOR]

This paper is dedicated to improving the sintering and conductivity of BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ (BZCYYb) by adding ZnO–CuO dual-sintering aids. The synergistic effects of liquid-sintering of Zn and B-site substitution of Cu on the sinterability and proton conductivity of BZCYYb are systematically investigated. X-ray diffraction (XRD) analysis of BZCYYb after addition of ZnO–CuO (BZCYYb-Zn-Cu) confirms the complete perovskite phase formation without any secondary phase. The substitution of Ce4+ (0.87 Å) with Zn2+ (0.74 Å) or Cu2+ (0.73 Å) induces a shift in XRD diffraction peak to higher angle due to a decrease in lattice constant. Energy dispersive X-ray spectroscopy analysis indicate a distinct distribution of Zn primarily at the grain boundaries, while Cu is predominantly located within the grains of BZCYYb-Zn-Cu. The addition of ZnO–CuO into BZCYYb results in a denser microstructure with larger average grain size. Furthermore, the substitution of Ce4+ by Cu2+ increases the concentration of oxygen vacancies and reduces activation energy. For BZCYYb-Zn-Cu, the proton conductivity reaches 4.52 × 10−2 S/cm at 750 °C, approximately 3 times higher than that of BZCYYb. This enhancement can be attributed to the synergistic effects of larger average grain size resulting from liquid phase sintering of Zn, low active energy, and high concentration of oxygen vacancies arising from Cu B-site substitution. BZCYYb-Zn-Cu is used as the electrolyte for anode support SOFC, and the single cell exhibits remarkable electrochemical performance and excellent stability in H 2 fuel. This research establishes a crucial theoretical foundation for the preparation and performance evaluation for large-size protonic ceramic cell. • Zn is mainly aggregated at grain boundaries, while Cu is mostly distributed in the grains bulk. • ZnO–CuO synergistically promote the sinterability and conductivity for BZCYYb. • The SOFC with BZCYYb-Zn1-Cu1 electrolyte exhibits high electrochemical performance. [ABSTRACT FROM AUTHOR]

This paper reports an extensive investigation on the structural, dielectric, ferroelectric and pyroelectric properties of 0.7Ba 1-x Sr x TiO 3 – 0.3Bi 0.5 Na 0.5 TiO 3 (x = 0.0, 0.5, 0.6, 0.7) ceramics synthesized via conventional solid-state reaction (SSR) technique. X-ray diffraction data confirms the presence of pure perovskite phase. The variation of lattice parameters with strontium concentration in 0.7Ba 1-x Sr x TiO 3 – 0.3Bi 0.5 Na 0.5 TiO 3 ceramics were evaluated using the Rietveld refinement of the XRD data. The variation of dielectric permittivity with temperature (ε' ∼ T) shows the diffused phase transition and all the parameters related to the relaxor ferroelectrics (relaxation coefficient, activation energy and freezing temperature) were evaluated. The energy storage properties of the as-prepared ceramics were evaluated using the room temperature PE loop. Amongst the as-prepared ceramics, the composition with x = 0.5 possesses the highest energy storage density of 0.46 J/cm3 with an efficiency of 90 %. The temperature dependent P-E loops were used to study the electrocaloric effect (ECE). The ECE calculations were performed using in-direct method based on Maxwell's thermodynamic relations. A maximum adiabatic temperature change of 0.32 K is achieved at 268 K under a small applied electric field of 25 kV/cm for the ceramic with Sr content x = 0.5. Additionally, electrocaloric responsivity ξ max = 0.13 K mm/kV was also found for the studied ceramics. The above results show that the ceramic 0.7Ba 1-x Sr x TiO 3 – 0.3Bi 0.5 Na 0.5 TiO 3 with the composition x = 0.5 is a viable lead-free option for application in solid state refrigeration. [ABSTRACT FROM AUTHOR]

Perovskite oxides have huge potential applications in carbon capture and utilization as oxygen transport membranes (OTM) and solid oxide fuel cell (SOFC) electrodes. SrFeO 3- δ -based perovskite material, as the promising candidate, possesses high mixed ionic-electronic conductivity, but its partial application is impeded by poor stability under CO 2 conditions. In this work, SrFe 0.9 M 0.1 O 3- δ (SFM, M = Fe, Al, Zr, Nb, W) ceramic membranes were synthesized to study the effects of different valence B-site ions doping on the stability and CO 2 adsorption process of perovskite oxides. The phase structure, thermal expansion property, CO 2 tolerance, and CO 2 absorption mechanism on surfaces of SFM were investigated systematically. B-site doping stables the pure cubic structure, improves the high-temperature structural stability, and reduces the thermal expansion coefficient (TEC) by increasing the lattice parameters and metal-oxygen average binging energy (ABE) of SFM. Moreover, density functional theory (DFT) calculations indicate that although B-site ions doping promotes the adsorption of CO 2 on the FeO 2 -terminated, it inhibits CO 2 adsorption on the Sr-O-Sr site after Zr4+, Nb5+, and W6+ doping, causing the reduction of the CO 2 desorption. The results offer new insights for designing perovskite oxides in the carbon neutralization field. • Different valence ions B-site dope SrFeO 3- δ perovskite oxide used in the CCUS. • SrFe 0.9 M 0.1 O 3- δ (SFM, M = Fe, Al, Zr, Nb, W) ceramic membranes are synthesized. • The increase of lattice parameters stabilizes the cubic structure of SFM. • The structure stability at high temperatures is improved by B-site ion doping. • The CO 2 adsorption mechanism on the SFM surfaces is revealed by DFT calculations. [ABSTRACT FROM AUTHOR]

This paper investigated the impact of Co ions doping on the structure, magnetic properties, and magnetocaloric effect for La 0.8 Sr 0.2 Mn 1- x Co x O 3 ceramics (LSMCO) by sol-gel method and first-principles calculations The use of first-principles calculations was provided for subsequent experiments. The sol-gel preparation of LSMCO ceramics and sintered at 950 °C for 10 h. It was shown that the samples' cell volume and lattice constants changed slightly with increasing Co2+ doping but remained a rhombohedral structure (No.167, R-3c space group) by statistics of TEM and XRD. The average particle size for the LSMCO ceramics ranged from 130 nm to 170 nm. LSMCO's chemical composition was verified by EDS and XPS and it was demonstrated that Co2+ was successfully doped. The oxidation state of La was found to be +3, Mn is a mixture of Mn3+ and Mn4+ valence states, and Co is a mixture of Co3+ and Co2+ valence states using XPS. In the vicinity of Tc, all samples presented the second-order magnetic phase transition from ferromagnetic to paramagnetic resorting to normalization and the Banerjee criterion. The Tc dropped from 292 K to 237 K with increasing Co2+ doping. The blocking temperature and the saturation magnetization were suppressed by the Co2+ substitution while the maximum magnetic entropy change of the LSMCO ceramics was observed to reduce as Co2+ increased. When the external magnetic field is 5 T, the La 0.8 Sr 0.2 Mn 0.95 Co 0.05 O 3 ceramics has a Tc of 292 K and a maximum magnetic entropy change value of 3.47 J/(kg K). [ABSTRACT FROM AUTHOR]

This study explores a novel method for fabricating Ca-α-sialon ceramics using a calcium aluminate oxide eutectic additive. Conventional sintering techniques for Ca-α-sialon ceramics employ nitrogen-containing additives to facilitate the Si–N bond substitution mechanism with Al–O and Al–N bonds. In this work, calcium aluminate additives are utilized, leading to the formation of Ca-α-sialon ceramics via carbothermal reduction processes and partial nitridation of aluminum oxide. The influence of varying calcium aluminate content (5, 10, 15, 30, and 40 wt%) on the phase composition of Ca-α-sialon ceramics, produced by hot pressing at 1650 °C in a nitrogen atmosphere, was investigated. Results indicate that increasing the calcium aluminate content leads to the formation of a β-sialon phase, which subsequently transforms into Ca-α-sialon. At 40 wt% calcium aluminate, complete conversion of α-Si 3 N 4 to Ca-α-sialon is achieved, with significant glassy phase formation at the grain boundaries. The study elucidates the relationship between calcium aluminate content, phase composition, lattice parameters, mechanical properties, oxidation resistance, and thermal expansion of the ceramics. [ABSTRACT FROM AUTHOR]

Ceramics of Li 2 Mg 2 GaTi 2 O 8 F (LMGTOF) were prepared by the traditional solid-state method. XRD and TEM results confirmed that a single phase of Li 2 Mg 2 GaTi 2 O 8 F, with an Fd-3m space group and a cubic spinel structure, was formed by the ceramics. It was shown by the results that the lattice parameters of the ceramics at 1050 °C were measured as a = b = c = 8.36576 Å, with a volume of V = 585.485549 Å3. Furthermore, it was observed through the analysis of the Raman peak at 718 cm−1 that an inverse relationship was exhibited between the Raman shift and ε r. Similarly, an opposing trend was also demonstrated between the Q × f value and FWHM. By bond valence analysis, it was shown that Mg2+, Ga3+, and Ti4+ ions were in a "rattling" state, and the large positive deviation between ε corr and ε theo was attributed to the strong "rattling" effect induced by the cations. At 1050 °C, the best microwave dielectric properties (ε r = 14.58, Q × f = 76,689 GHz, and τ f = −52 ppm/°C) were exhibited by LMGTOF ceramics. [ABSTRACT FROM AUTHOR]

The (Al 1-x Cr x) 2 O 3 solid solution (ACS) is expected to be an low pollution chromium source for high-performance alumina-chromium oxide refractory materials. In this work, the effects of Cr 2 O 3 content and reaction conditions on the solid solution behavior in the Al 2 O 3 -Cr 2 O 3 system were explored and the mechanism was revealed. The relationship between the lattice parameters of the formed ACS phase and the content of Cr 2 O 3 was closer to a linear one as the temperature rose, serving as an indicator for a higher degree of reaction. The solid solution reaction between Al 2 O 3 and Cr 2 O 3 was governed by the diffusion processes of Al3+ and Cr3+ at 1300–1500 °C and 1200 °C, respectively, and thus the increase of Cr 2 O 3 content slowed the solid solution reaction at a low temperature whereas promoted it at elevated temperatures. The diffusion process of solid solution reaction within the Al 2 O 3 -Cr 2 O 3 system was consistent with the Cater model; The diffusion activation energy (E a) decreased as the content of Cr 2 O 3 increased at 1300–1500 °C. When the content of Cr 2 O 3 increased from 25 to 60 mol%, the diffusion activation energy decreased from 92.48 to 86.49 kJ/mol−1, which was attributed to the augmentation in the diffusion rate of Cr3+ caused by the increase of Cr 2 O 3 content and its vapor-phase transport mechanism at high temperatures. [ABSTRACT FROM AUTHOR]

CuInP2S6 (CIPS) is an emerging 2D ferroelectric material known for disrupting spatial inversion symmetry due to Cu(I) position switching. Its ferroelectricity strongly relies on the Cu(I) atom/ion occupation ordering and dynamics. Nevertheless, the accurate Cu(I) occupations and correlated migration dynamics under the externally applied energy, which are key to unlocking ferroelectric properties, remain controversial and unresolved. Herein, an atomic-level direct imaging through aberration-corrected scanning transmission electron microscopy is performed to precisely trace the Cu(I) dynamic behaviours under electron-beam irradiation along (100)-CIPS. It clearly demonstrates that Cu(I) possesses multiple occupations, and Cu(I) could migrate to the lattice, vacancy, interstitial and interlayer sites between the InS6 octahedral skeletons of CIPS to form local CuxInP2S6 (x = 2-4) structure. Cu(I) multi-occupations induced lattice stress results in a layer sliding along the b-axis direction generating a sliding size of 1/6 b lattice constant. The CuxInP2S6 (x = 2-4) exists in a type of dynamic structure, only metastable with electron dose over 50 e− Å−2, thus generating a dynamic process of C u x In P 2 S 6 (x = 2 − 4) ⇌ CuIn P 2 S 6 , a completely unreported phenomenon. These findings shed light on the unveiled mechanism underlying Cu(I) migration in CIPS, providing crucial insights into the fundamental processes that govern its ferroelectric properties. The authors demonstrate that Cu(I) possesses multiple occupations, and Cu(I) migrate to the lattice, vacancy, interstitial and interlayer sites between the InS6 octahedral skeletons of CuInP2S6 to form local CuxInP2S6 (x = 2-4) structure. [ABSTRACT FROM AUTHOR]

When stacked into heterostructures, layered transition metal dichalcogenides (TMDCs) exhibit peculiar electronic and optical properties that may differ substantially from those of their constituents and that largely depend on the level alignment. For example, the MoTe2/WSe2 heterobilayer exhibits a type I band lineup, which can be exploited in emitting devices but limits charge separation. In this first‐principle study based on density functional theory and many‐body perturbation theory, strain is proposed as an effective means to make MoTe2/WSe2 a type II heterostructure. By exploring several configurations where biaxial strain is applied to either or both monolayers, the top of the valence band and the bottom of the conduction band are found at different points in k‐space leading to an indirect‐to‐direct bandgap transition when the lattice constant of WSe2 is expanded by 3.2% or more. In terms of optical properties, all considered systems exhibit a first dark excitation, consistently shifting in energy with the direct electronic gap, while the absorption onset does not vary significantly with strain. Our findings suggest strain as a powerful tool for fine tuning the electronic and optical properties of TMDC heterostructures while preserving their fundamental characteristics, thus opening new avenues for designing optoelectronic applications. [ABSTRACT FROM AUTHOR]

This study investigated the effect of neodymium (Nd) on the crystal structure and magnetocaloric properties of lanthanum–strontium manganites (La0.7−xNdxSr0.3MnO3, 0 ≤ x ≤ 0.4), synthesized by assisted high-energy ball milling. Rietveld analysis from X-ray diffraction disclosed that Nd3+ did not promote crystallographic phase transitions. The rhombohedral crystal structure remained in the R-3c space group for all the compositions, with slight changes in lattice parameters. The defect model allowed the quantification of the Mn4+ occupancy, which is in the range from 0.20 to 0.26 mol, for 0.1 and 0.4 mol of Nd3+, respectively. The presence of Mn4+ promoted further ferromagnetic interactions, increasing systematically the saturation magnetization, from 65 A·m2·kg−1 to 73 A·m2·kg−1, and a diminution in the Curie temperature from 364 to 255 K, for 0 and 0.4 mol of Nd3+, respectively, obtained by temperature-dependent magnetization measurements. The doped manganite with 0.35 mol of Nd3+ showed a maximum of entropy change of 3.73 Jkg−1 K−1 at 1.8 T near room temperature, with a relative cooling power of 82 Jkg−1 and temperature-averaged entropy change, TEC(3) and TEC(10), of 3.53 and 3.06 Jkg−1 K−1, respectively. It is demonstrated that the presence of Nd3+ modulates the Curie temperature near room temperature and enhances the magnetocaloric properties at low magnetic fields, making these manganites a promising material for magnetocaloric applications. [ABSTRACT FROM AUTHOR]

In this research, different Co2+ doped ZnO nanoparticles (NPs) were hydrothermally synthesized by an environmentally friendly, sustainable technique using the extract of P. capillacea for the first time. Co-ZnO was characterized and confirmed by FTIR, XPS, XRD, BET, EDX, SEM, TEM, DRS UV–Vis spectroscopy, and TGA analyses. Dislocation density, micro strains, lattice parameters and volume of the unit cell were measured using XRD results. XRD suggests that the average size of these NPs was between 44.49 and 65.69 nm with a hexagonal wurtzite structure. Tauc plot displayed that the optical energy bandgap of ZnO NPs (3.18) slowly declines with Co doping (2.96 eV). Near complete removal of the ciprofloxacin (CIPF) antibiotic was attained using Green 5% of Hy-Co-ZnO in the existence of visible LED light which exhibited maximum degradation efficiency (99%) within 120 min for 30 ppm CIPF initial concentration. The photodegradation mechanism of CIPF using Green Hy-Co-ZnO NPs followed the Pseudo-first-order kinetics. The Green Hy-Co-ZnO NPs improved photocatalytic performance toward CIPF for 3 cycles. The experiments were designed using the RSM (CCD) method for selected parameters such as catalyst dosage, antibiotic dosage, shaking speed, and pH. The maximal CIPF degradation efficiency (96.4%) was achieved under optimum conditions of 39.45 ppm CIPF dosage, 60.56 mg catalyst dosage, 177.33 rpm shaking speed and pH 7.57. [ABSTRACT FROM AUTHOR]

The coalescence of nanocrystals that occurs during low-temperature thermal treatments during the purification of hydroxyapatite from pigs has not yet been studied in the context of low-temperature environmentally friendly purification. To preserve the nature of hydroxyapatite, two extraction methods were investigated: Route 1 (autoclave and Soxhlet) and Route 2 (calcination at low temperatures with different times). The focus is on observing the effectiveness of removing fats and proteins while maintaining crystallite size and morphology. DSC showed that coalescence of crystallites occurred at 452, 566, 648, and 704 °C. Raw has a higher IR FWHM (phosphate band) due to the organic material; R1 had a lower FWHM (partial removal of lipids and proteins). Increasing the calcination temperature decreases the FWHM, indicating a shift in vibrational states from surface to bulk, leading to an increase in apparent crystallite size due to coalescence. For 20–80 h at quasi-stable temperatures of 400 and 500 °C, no significant changes occur in the IR spectrum. X-ray diffraction indicates the removal of organic material during calcination, as the peaks become clearer with increasing temperature. The crystallite size is not affected and remains in similar ranges. Purification with hydroxide shows an increase in both lattice parameters, in addition to the fluctuations that occur due to the ionic substitutions that naturally occur in biogenic HAp. And the TEM study confirms that the changes in apparent size from 2D to 3D are the result of the phenomenon of interplanar coalescence at low temperatures that occurs in sintering processes. [ABSTRACT FROM AUTHOR]

β‐Ga2O3 is an emerging ultra‐wide bandgap semiconductor with great promise for power electronics and optoelectronics. Alloys in the In2O3‐Ga2O3 system are interesting for optoelectronic applications, particularly where bandgap tuning is desirable. Herein, β‐(InxGa1–x)2O3 alloys with target compositions x = 0.025 or 0.10 are grown from the melt using the Czochralski and vertical gradient freeze techniques. Growth with 10 mol% In yields only small, needle‐like crystals, while 2.5 mol% In allows growth of centimeter‐sized single crystals. A substantial degree of indium segregation is unveiled by spatial measurements of lattice parameters and the bandgap. The bandgap decreases by a maximum of 0.28 eV in the case of the highest In content crystals. Z‐contrast transmission electron microscopy confirms a solely octahedral coordination of In in the β‐Ga2O3 lattice. With indium concentrations higher than 2.5 mol%, samples contain micron‐scale voids that impart a dark coloration. All measured crystals are electrically conductive, with carrier concentrations varying 1016–1017 cm−3 depending upon the location of the sample in the growth. Lastly, a unique luminescence with unknown origin centered around 2.0 eV is revealed by photoluminescence spectroscopy. [ABSTRACT FROM AUTHOR]

In this computational study, density functional theory (DFT) is employed to analyze the structural, electronic, elastic, and topological properties of ternary compounds MXY (M = Ti, Sn, Ir, X = Se, Te, Y = Se, Te). The effects of spin–orbit interaction and pressure‐induced strain are investigated to understand their influence on the stability, mechanical properties, and electronic behavior, paving the way for potential technological applications. The findings confirm that these compounds are inherently stable in nonmagnetic phases, with spin–orbit interaction critically influencing their energy–volume landscapes. The calculated lattice parameters, ratios of lattice constants, and bulk moduli closely align with existing data, confirming the reliability of our approach. Mechanical assessments reveal distinct behaviors: IrSe2 exhibits the highest stiffness due to pronounced covalent bonding, contrasting with SnTe2's elastic anisotropy and SnSeTe's nearly isotropic properties. Electronically, most compounds show metallic characteristics, except SnSe2, which behaves as a semiconductor with an indirect, pressure‐sensitive energy bandgap. Topological analysis under varying hydrostatic pressures indicates band inversions in TiSe2, IrSe2, and SnSeTe, suggesting topological phase transitions absent in other compounds. This study enriches our understanding of these materials and refines the application of DFT in material design. [ABSTRACT FROM AUTHOR]

Ammonium‐calcium mixed‐cation pentaborate NH4Ca[B5O7(OH)4]·H2O has been synthesized for the first time. Single‐crystal X‐ray diffraction analysis reveals that it crystallizes in the triclinic space group P‐1 with lattice parameters a = 6.7042(3) Å, b = 7.1859(3) Å, c = 10.7447(4) Å, α = 100.304(3), β = 97.774(3), γ = 96.972(3). The structure is characterized by 1D boron–oxygen chains composed of [B5O7(OH)4]3− polyanions that are further interspaced by Ca2+, NH4+ cations, along with lattice water molecules. The phase purity and thermal stability of the as‐synthesized sample were confirmed by XPRD and TG‐DSC analyses. Experimental UV–vis diffuse reflectance spectroscopy coupled with Urbach fitting indicates a direct bandgap of 4.50 eV, contrasting with theoretical calculations that suggest an indirect bandgap of 5.53 eV. Additionally, both theoretical computation and polarized light experimental test indicate that NH4Ca[B5O7(OH)4]·H2O exhibits moderate birefringence. [ABSTRACT FROM AUTHOR]

The structural, dynamical, and thermodynamic properties of zinc‐blende (ZB) mercury selenide (HgSe) and cadmium selenide (CdSe) were systematically explored using an ab initio pseudopotential approach based on the density functional theory (DFT). The optimized lattice constants are in excellent agreement with the available experimental and theoretical results. The electronic properties show semiconducting behavior with a direct bandgap of 0 and 0.36 eV for HgSe and CdSe, respectively. Also, using the linear response approach, the detailed vibration properties of HgSe and CdSe are obtained. According to the calculated phonon dispersion, it is concluded that HgSe and CdSe are dynamically stable in the ground state; several peculiarities in the dispersion curves of these materials are generally similar, but the zone‐boundary frequencies and zone‐center optical frequencies of HgSe are lower than those of CdSe. The phonon frequencies at the high‐symmetry points Γ, X, and L for HgSe and CdSe are in good agreement with the other theoretical reported. On the other hand, the dielectric properties are investigated and discussed. The results show that the dielectric tensor is diagonal, and the Born effective charge tensor is also isotropic. Finally, based on the lattice dynamical properties, we investigate the thermodynamic properties of both compounds, such as Helmholtz free energy F, internal energy E, entropy S, and specific heat Cv. The results show that HgSe and CdSe exhibit similar but slightly different behaviors in terms of its thermodynamic properties, which is expected because the atoms Hg and Cd are in the same group and exhibit a different atom mass. Most of the results presented in this study are novel and should provide a useful reference for future studies. [ABSTRACT FROM AUTHOR]

Y3+ : CaF2 powders were synthesized by chemical coprecipitation method, and transparent ceramics were fabricated by vacuum hot pressing sintering method. Characteristics of the as-synthesized powders were investigated by XRD, SEM and TEM techniques, the relationship between microstructure and transmittance of transparent ceramics were also analyzed. Crystal structures of as-synthesized Y3+ : CaF2 powders belong to single fluorite phase. With the Y3+ doping content increases, the average particles sizes decrease and the lattice constants increase from 5.452 1 Å to 5.465 5 Å. The 5% Y3+ :CaF2 transparent ceramics sintered at 900 °C for 3 h exhibits the highest transmittance, and the transmittance at 500 and 1 500 nm are 73. 1% and 86.4%, respectively. Microstructure of ceramics are modified by the Y3+ doping content and sintering temperatures. For a low growth velocity, it is not easy to eliminate the residual pores, while for a higher growth velocity, residual pores are easily embedded within grains. Both cases will reduce the transmittance of transparent ceramics. This work provides a reference for the preparation of high-quality composite CaF2 transparent ceramics. [ABSTRACT FROM AUTHOR]

Local lattice distortion (LLD) is a salient feature of bcc-structured refractory high-entropy alloys (RHEAs), closely associated with their mechanical properties. To quantify the extent of LLDs in RHEAs, the pair distribution function (PDF) analysis has been identified as a promising approach. However, the commonly observed chemical segregation within these alloys introduces challenges in accurately determining LLDs. In this study, the effect of chemical segregation on LLD quantification was investigated through fitting simulated two-phase composite PDFs, representing segregated microstructures, with a single-phase model and evaluating the errors to assess the accuracy and reliability of small-box analysis in this context. The results show that the errors introduced by chemical segregation increase with increasing lattice parameter difference, and the fitting quality gradually deteriorates to a point where it no longer adequately describes the data. We found that the lattice parameter difference should be below 1% for precise and reliable LLD measurements in bcc-structured RHEAs. Additionally, we observed that while the scattering length variation due to segregation does affect LLD quantification, its effect is comparatively minor. [ABSTRACT FROM AUTHOR]

III–V compound semiconductors, such as indium arsenide (InAs), are crucial in the fields of electronics and optoelectronics due to their unique properties, including a narrow bandgap, high electron mobility, low effective electron mass, and outstanding optoelectronic performance. However, the lattice constant mismatch of 7.2% between InAs and gallium arsenide (GaAs) leads to a high dislocation density in the InAs epilayer, typically around 109 cm−2 or higher when InAs is directly grown on GaAs (001). A common traditional approach to reduce material defect density involves using a compositionally graded buffer structure, which requires a thickness of several micrometers. This paper presents an innovative method for growing device-quality InAs epilayers on GaAs (001) substrates through an InAs coalesced quantum dot buffer (CQDB) layer. Remarkably, the InAs CQDB method requires a thickness of only several tens of nanometers, leading to significant improvements in film quality. Utilizing the InAs CQDB layer allows for a substantial reduction in dislocation density from 1.8 × 109 to 3.6 × 107 cm−2. The findings of this study provide a crucial research foundation for addressing lattice mismatch challenges in epitaxial growth, particularly for those investigating methods to integrate different materials in advanced device applications. [ABSTRACT FROM AUTHOR]

As new alloys are being developed for additive manufacturing (AM) applications, questions related to the temperature-dependent structural and compositional stability of these alloys remain. In this work, the benefits and limitations of a unique method for testing this stability are presented. This system employs the use of polychromatic synchrotron light to perform energy-dispersive x-ray diffraction (ED-XRD) on an electrostatically levitated sample at high temperatures. In comparison with a traditional angular-dispersive setup, the container-less electrostatic levitation method has unique advantages, including quicker acquisition times, simultaneous compositional information through fluorescence emissions, a reduction in background noise, and, importantly, concurrent/subsequent measurement of thermophysical properties. This combined method is ideal for phase transition studies by holding the levitated sample at a stable position and temperature through controlled heating and temperature management. To illustrate these capabilities, we show ED-XRD data of the well-known martensitic phase transition (hcp to bcc) in Ti–6Al–4V. In addition, results from the novel alloy Ni51Cu44Cr5 are presented. This alloy is shown to maintain an fcc structure upon heating. However, the concentration of Cu is reduced at high temperatures, resulting in a decrease in the lattice constant. As concurrent thermophysical properties are probed, these preliminary structure and composition experiments demonstrate the capabilities of this technique to determine the composition–processing–structure–properties of metal alloys for AM. [ABSTRACT FROM AUTHOR]

Magnetic Resonance Imaging (MRI) is a medical device that relies on magnetic fields generated by superconducting wires to detect brain tumors. To generate magnetic fields, the medical device employs Niobium-based superconductor. This superconductor has several disadvantages, such as low critical temperature, limited raw material resources, and expensive raw material prices. Magnesium diboride (MgB2) has a critical temperature of 39 K, allowing it to be a suitable replacement for Niobium-based superconductors. In this research, a comprehensive analysis was conducted on the effect of adding nano-SiC on the structure and electrical transport properties of MgB2 superconducting wire. An investigation into the mechanical properties of the wire sheath was also done to determine if the wire can proceed to the next process. Using the Powder in Tube (PIT) method, followed by a cold deformation scheme, MgB2-based monofilament wire was manufactured. The findings of the X-Ray Diffraction (XRD) test confirm that the lattice constant -a of the MgB2 hexagonal phase decreases with increasing nano-SiC content addition. This lattice distortion causes the critical temperature of the MgB2 superconducting phase to drop from 37.99 K to 36.94 K. The addition of 5 wt% nano-SiC at 290 K causes the material to become more insulating, as evidenced by an increase in resistivity value from 256.18 µΩ.cm to 411.61 µΩ.cm. The mechanical characteristics of sheath demonstrate recovery following a cold reduction of around 56.25% and subsequent heating at 1073 K. The ultimate tensile strength and average hardness value are 585 MPa and 215.30 HV, respectively. [ABSTRACT FROM AUTHOR]

2D diffraction gratings based on Gauss lattices are a class of nonperiodic lattice in which the sites are located at Rj1,j2=j1ndx̂+j2ndŷ${\bf R}_{j_1,j_2}=j_1^nd\hat{\bf x} + j_2^nd\hat{\bf y}$ with j1,j2∈{...,−1,0,1,...}$j_1,j_2\!\in \! \lbrace \ldots, -1,0,1,\ldots \rbrace$, n∈{2,3,4,...}$n\! \in \! \lbrace 2,3,4, \ldots \rbrace$, dx̂$d\hat{\bf x}$ and dŷ$d\hat{\bf y}$ orthogonal primitive vectors in the plane, and d$d$ the lattice constant. Gauss lattices are treated for various orders n$n$, and discuss applications for gratings separable in the x$x$ and y$y$ directions. These gratings, while geometrically very simple, produce complex pseudorandom diffraction patterns, though they exhibit rotational invariance and strong correlations along the x$x$ and y$y$ directions. Then how to generalize the approach is discussed to attain nonseparable gratings where such features are suppressed. The result is an intensity distribution like that of diffuse light, the effect originating in the breaking of the hidden translational invariance of the Gauss lattice. [ABSTRACT FROM AUTHOR]

Tailoring the electronic and optical properties of nitride‐based alloys for optoelectronic device applications in the ultraviolet and red spectral range has attracted significant attention in recent years. Adding boron nitride (BN) to indium gallium nitride (In,Ga)N alloys can help to control the lattice mismatch between (In,Ga)N and GaN and may thus allow to reduce strain‐related defect formation. However, understanding of the impact of BN on the electronic properties of III‐N alloys, in particular the influence of experimentally observed boron atom clustering, is sparse. This work presents first‐principles calculations investigating the electronic properties of highly mismatched (B,In)N alloys with boron contents between 2% and 7%. Special attention is paid to the impact of the alloy microstructure. While the results show that the lattice constants of such alloys largely agree with lattice constants determined from a Vegard approximation, the electronic structure strongly depends on the local boron atom configuration. For instance, if boron atoms are dispersed throughout the structure and are not sharing nitrogen atoms, the band gap of (B,In)N alloys is largely unaffected and stays close to the gap of pristine InN. However, in the case of boron atom clustering, i.e., when boron atoms are sharing nitrogen atoms, the band gap can be strongly reduced, often leading to a metallic state in (B,In)N alloys. These strong band gap reductions are mainly driven by carrier localization effects in the valence band. Our calculations thus show that the electronic structure of (B,In)N alloys strongly depends on the alloy microstructure and that boron atom clustering plays an important role in understanding the electronic and optical properties of these emerging materials. [ABSTRACT FROM AUTHOR]

This study aimed to compare and summarize the mullitization mechanism of the sillimanite group minerals and investigated its effect on the mechanical properties of Al2O3‐SiC‐C gunning materials. By comparing the phase composition and microstructure of kyanite, andalusite, and sillimanite at different temperatures, the mullitization mechanism of sillimanite group minerals was clarified. Furthermore, the Al2O3‐SiC‐C gunning materials with sillimanite group minerals addition were prepared by bauxite and fused brown corundum as aggregates, fused white corundum (≤0.045 mm), SiC (≤0.075 mm), α‐Al2O3 (≤10 µm), pitch sphere, SiO2 micropowder (≤2 µm) as a matrix, and silica sol as a binder. Then, the effect of the addition of sillimanite group minerals on the mechanical properties of Al2O3‐SiC‐C gunning materials was characterized. The results indicate that kyanite requires the lowest temperature for mullitization compared to andalusite and sillimanite. The mullitization process involves the migration of Al3+ and Si4+, resulting in a decrease in the lattice constant of sillimanite group minerals followed by the production of mullite and SiO2. Incorporating sillimanite group minerals into Al2O3‐SiC‐C gunning materials effectively controls their linear change rate after firing while enhancing their mechanical properties. Notably, the addition of kyanite yields superior performance in Al2O3‐SiC‐C gunning materials. [ABSTRACT FROM AUTHOR]

In this study, the element substitution technique was utilized to create a solid solution, which in turn allowed for the manipulation of lattice parameters. The microwave dielectric properties of Mg 1.8 R 0.2 Al 4 Si 5 O 18 (R=Mg, Ni, Zn, Cu, Sr, Ca, Ba) ceramics were investigated following the substitution of Mg2+ ions. The influence of microstructural alterations on these properties was also examined. A cordierite solid solution was formed when R = Ni, Cu, Sr, or Ba; however, an additional phase emerged when R = Zn, Sr, or Ca. The complete substitution influenced the relative dielectric constant of Mg 1.8 R 0.2 Al 4 Si 5 O 18 due to the ionic polarizability and the average ionic property of the R ion. The Q × f value was found to be related to the crystal lattice energy, while the τ f value was primarily affected by octahedral distortion. The appearance of a secondary phase altered the primary factors influencing the dielectric properties of the Mg 1.8 R 0.2 Al 4 Si 5 O 18 ceramics. Among the substitutions tested, Mg 1.8 Ni 0.2 Al 4 Si 5 O 18 exhibited superior microwave dielectric properties with ε r = 4.64, Q × f = 44,770 GHz, and τ f = −32 ppm/°C. [ABSTRACT FROM AUTHOR]

Wafer-scale Mesoporous GaN (MP-GaN) distributed Bragg reflectors (DBRs) with high reflectivity (>99 %) are prepared by electrochemical etching, and then are used as the substrate in growth of large-area europium (Eu) doped Ga 2 O 3 thin films via the pulsed laser deposition (PLD) technology. X-ray diffraction analysis shows that all Ga 2 O 3 thin films with different doping concentration have monoclinic β-Ga 2 O 3 structures with [−201] orientation. The angle of β-Ga 2 O 3 (−201) peak decreases as Eu contents increases, which is due to the fact that Eu3+ substituting for Ga3+ rises the lattice constant of β-Ga 2 O 3. With the increase of Eu doping, the photoluminescence (PL) of the Ga 2 O 3 thin film is enhanced. The epitaxial relationship is β-Ga 2 O 3 (−201) || GaN (0001) with β-Ga 2 O 3 [010] || GaN [-12-10]. Compared to the sample without DBRs, wafer-scale Ga 2 O 3 thin films with MP-GaN DBRs exhibit a markedly increased PL intensity, which is attributed to improved internal quantum efficiency (IQE) of Ga 2 O 3 thin films and enhanced light extraction efficiency (LEE) related to the light reflection effect of MP-GaN DBRs. [ABSTRACT FROM AUTHOR]

Crystalline Sm3+ substituted V-type hexaferrites Sr 1-x Sm x Fe 8 SnO 15 with composition (x = 0.00, 0.02, 0.06, 0.10) were synthesized using hydrothermal method. With the substitution of Sm3+ ions, the lattice constant 'c' experienced a decrement from 54.4600 Å to 53.0200 Å while the value of lattice constant 'a' firstly increased and then decreased. The crystallite size varied from 37.95 to 50.86 nm. The spherical shape of particles was analyzed by Atomic Force Microscopy (AFM). The VSM analysis revealed that the samples inherent the soft magnetic properties as evidenced by the coercivity value being below 1 k Oe which exemplifies its usefulness in the field of microwave absorption properties. The successive production of heat during hyperthermia analysis indicated the use of this material in cancer cell treatment. The UV visible spectroscopy technique was utilized to investigate many parameter including absorption, Urbach-energy, and band gap. It can be affirmed that the prepared material might be useful for photo-catalytic purposes and hyperthermia applications. [ABSTRACT FROM AUTHOR]

In this study, Ca substitution and carrier doping effect on phase formation temperature and physical/superconducting properties of (Eu 0.9-x Ca x La 0.1)(Fe 0.97 Co 0.03)As 2 ((Eu,Ca)112, x = 0–0.4) compounds were investigated. The best synthesis condition for obtaining pure phases vary (850–900 °C) depending on the Ca substitution amount. Ca substitution in the EuFeAs 2 structure induced a structural transformation from orthorhombic I 2 mm to monoclinic P 2 1 / m symmetry. Single crystals of EuFeAs 2 and (Eu 0.9 La 0.1)FeAs 2 were grown and their crystal structures were determined. Density functional theory calculations confirmed the transformation and stability of the La-doped Eu112 crystal structure with Ca substitution. Compared with the parent compound EuFeAs 2 , the effective substitution of Ca reduced the lattice constants. The magnetic and transport properties of (Eu 0.9- x Ca x La 0.1)(Fe 0.97 Co 0.03)As 2 compounds were studied using the temperature and field dependence of the magnetization and electrical resistivity measurements. Ca substitution suppressed the magnetic ordering of Eu and gradually reduced the Néel temperature T N Eu. As determined by the magnetization and electrical resistivity data, the onset of critical temperature (T c) values increased with Ca substitution increment from 26 K to 32.2 K and 31 K–34.8 K, respectively. Ca substitution slightly increased the upper critical field values, while the coherence length ξ values were slightly decreased. The Ca substitution and sintering temperature dependence of superconductivity, upper critical fields, lower critical fields, and Eu-related magnetic transitions were extracted. The new series of Eu-containing iron-based superconductors with high T c provides an interesting playground in this field. [ABSTRACT FROM AUTHOR]

Textile dyeing releases over 80% of industrial effluents without proper treatment. Dye discharged into effluents typically needs degradation before release into aquatic environments. In this regard, the present paper reports the nanocomposite copper oxide/polyaniline (CuO/PANI) is successfully synthesized by in situ chemical oxidative polymerization method and investigates their catalytic activity against organic dyes and nitro compounds. CuO is synthesized by colloidal sol–gel method using oxalic acid as capping agent to obtained desired morphology. The elemental composition, unit cell and lattice parameters of nanocomposite are characterized by using XRD. The XRD revealed that nanoparticles are extremely crystalline, but nanocomposite is amorphous because of the presence of polymer. The structural and elemental analysis of CuO and CuO/PANI is confirmed by SEM and EDX analysis. FTIR spectra of CuO showed bending vibration, while CuO/PANI showed the presence of benzenoid and quinoid rings. Catalytic productivity of the CuO and CuO/PANI as catalysts in degradation of dyes and reduction of nitro compounds is also studied. The degradation and reduction processes are monitored through the utilization of UV–Vis spectrophotometer. The catalytic activity of both catalysts is evaluated by several parameters including kapp, degradation/reduction time, % degradation/reduction, degraded/reduced concentration and half-life. Among all substrates, highest kapp is 0.0653 min−1 for CV by CuO, while 0.0502 min−1 for EBT by CuO/PANI due to large surface area. On degradation and reduction rate of substrates, the impact of functional group type and orientation, bond type and steric hindrance is also investigated. [ABSTRACT FROM AUTHOR]

This paper investigated the structural properties of nano-crystalline Cd2+ doped cobalt ferrite (C01-xCdxFe2O4) nanoparticles were synthesized by co-precipitation method. X-ray diffraction study revealed the formation of mono phase cubic spinels. The crystallite size was found to be increased from 17 to 38 nm with increase of cadmium concentration. The other structural parameters like lattice constant (a), volume (V), hopping lengths (LA and LB), bond lengths (A-O and B-O), ionic radii (rA and rB), X-ray density (Dx), microstrain (e) and dislocation density (OD) were also estimated. Here, W-H and Size-Strain Plot methods were used for obtaining the values of lattice strain and crystallite size from the X-ray diffraction peak broadening analysis. Each method of analysis was different result because, the variation was found in calculated parameters. [ABSTRACT FROM AUTHOR]

AlxCoCuNiTi (x = 0, 0.4, and 1) high-entropy alloy coatings on 45 steel substrates were prepared by laser cladding, and their phase structure, microstructure, element partition, and wear behavior were investigated. The results show that the AlxCoCuNiTi (x = 0, 0.4, and 1) coatings have a dual-phase structure of FCC and BCC. With the increase of x from 0 to 1, the content of the FCC phase decreases from 66.9 wt.% to 14.3 wt.%, while the content of the BCC phase increases from 33.1 wt.% to 85.7 wt.%. When x = 0.4, the lattice constants of the two phases are the largest, and their densities are the smallest. The microstructure of the AlxCoCuNiTi (x = 0, 0.4, and 1) coatings is composed of BCC-phase dendrites and FCC-phase interdendrite regions. Ti is mainly enriched in the primary phase or BCC dendrites, Cu is enriched in the interdendrite regions, and Al is enriched in the dendrites. The friction coefficients of AlxCoCuNiTi (x = 0, 0.4, and 1) coatings during wear tests are 0.691, 0.691, and 0.627, respectively. The lowering of the wear friction coefficient when increasing the Al content is mainly related to the change in phase structure, microstructure, and wear mechanism. [ABSTRACT FROM AUTHOR]

Upon solidification, graphitic cast irons undergo a volume change whose amplitude depends on two opposite terms, the contraction associated with austenite formation and the expansion due to graphite crystallization. During cooling after solidification, further precipitation of graphite occurs that continuously changes the physical properties of the material and possibly affects the eutectoid transformation that transforms the matrix from austenitic to ferritic or ferritic-pearlitic. This work intended to study the density of graphitic cast irons at high temperature, i.e., in the temperature range where the matrix is austenitic. High-temperature laboratory X-rays have been carried out on several alloys containing various carbon and silicon contents to characterize the austenite mean lattice parameter. By complementing these results with literature data, a statistical analysis was carried out that expresses the austenite mean lattice parameter as a function of temperature and composition, evidencing the high uncertainty related to the austenite carbon content. Finally, one of the investigated alloys was submitted to a simultaneous dilatometry and X-ray analysis in a synchrotron from room temperature to 1050 °C. The data are used to discuss the austenite lattice parameter prediction and the possibility of density prediction. [ABSTRACT FROM AUTHOR]

This study investigates the design of additive manufacturing for controlled crack propagation using process parameters and lattice structures. We examine two lattice types—octet-truss (OT) and diamond (DM)—fabricated via powder bed fusion with Ti-6Al-4V. Lattice structures are designed with varying densities (10%, 30%, and 50%) and process using two different laser energies. Using additive-manufactured specimens, Charpy impact tests are conducted to evaluate the fracture behavior and impact energy levels of the specimens. Results show that the type of the lattice structures, the density of the lattice structures, and laser energy significantly influence crack propagation patterns and impact energy. OT exhibits straighter crack paths, while DM demonstrates more random fracture patterns. Higher-density lattices and increased laser energy generally improve the impact energy. DM consistently outperformed OT in the impact energy for angle specimens, while OT showed superior performance in stair specimens. Finally, a case study demonstrates the potential for combining OT and DM structures to guide crack propagation along predetermined paths, offering a novel approach to protect critical components during product failure. [ABSTRACT FROM AUTHOR]

Anomalous thermal expansion, or other words, negative thermal expansion (NTE), resulting from the lattice contraction upon temperature increasing, has been an enduring topic for material science and engineering. The variation of a lattice go with the temperature is straightly originated from its electronic structures and is inseparable from those physical properties. In the past several decades, many efforts have been made to searching new series of NTE compounds or control the thermal expansion performance in order to supply various demands of different extreme applications. These development of new NTE systems also dependences on the theoretical studies. Here, we carried out theoretical calculation on CrB2 and FeZr2 with anisotropic negative thermal expansion. Intriguingly, theoretical calculations reveal that the binding of either Cr-Cr pair or Fe-Fe pair is relatively small. The results reveal that the origin of NTE is the ordered magnetic state during the increasing of temperature. The localized electrons would prevent the lattice parameters increase with heating, which shows macroscopic NTE phenomenon. [ABSTRACT FROM AUTHOR]

Phase composition, microstructure, and mechanical properties of spark plasma sintered (SPSed) AlCrFeNiX (X = Co, Cu, and CoCu) high entropy alloys (HEAs) were investigated. The results show that gas‐atomized AlCrFeNiCo and AlCrFeNiCu HEAs exhibit the single body‐centered cubic (BCC) phase, while a dual‐phase (face‐centered cubic (FCC) + BCC) structure is observed in AlCrFeNiCoCu HEA. After spark plasma sintering, an FCC phase with different lattice parameters can be observed in all three HEAs except for the BCC phase. FCC1 phase enriched in Fe‐Cr and FCC2 phase enriched in Cu appear in SPSed AlCrFeNiCo and AlCrFeNiCu HEAs, respectively, while both FCC1 and FCC2 phases are precipitated in SPSed AlCrFeNiCoCu HEA. The SPSed AlCrFeNiCoCu HEA has the largest fraction of the FCC phase (33%), while the lowest fraction of the FCC phase (12%) is observed in the SPSed AlCrFeNiCu HEA. Furthermore, the brittle and hard σ phase is also precipitated in SPSed AlCrFeNiCo HEA. The SPSed AlCrFeNiCo HEA possesses the highest hardness of 465 HV and compressive yield strength of 1175 MPa, which is attributed to the high volume fraction of BCC phase and σ phase, while the SPSed AlCrFeNiCoCu HEA shows the lowest hardness of 363 HV and compressive yield strength of 1024 MPa due to the highest volume fraction of FCC phase. [ABSTRACT FROM AUTHOR]

Prussian blue analogues (PBAs) are a class of promising materials for capacitive deionization. However, the kinetic mismatch between their slow ion storage rate and the demand from short‐time desalination severely limits their desalination performance. Here, a group of structure‐tuneable Ni‐Mn PBAs have been developed by a combination strategy of surface‐protected chemical etching and Ostwald ripening to study their ion storage kinetics. Treating them as demos, the characterizations and investigations, e.g., in situ XRD in a three‐electrode system, dynamic impedance, finite element simulation, and DFT calculations etc., reveal that the slow ion diffusion caused by the severe agglomeration of the nanoparticles and the unsuitable lattice parameter controls the final desalination behavior. Therefore, the correspondingly optimized sample (HC‐t) possessing a microscale hollow structure, nanoscale shell thickness, and expanded lattice, displays a fast ion storage kinetics with the ratio of surface‐controlled current as high as 82% at a scan rate of 20 mV s−1. Consequently, it delivers an impressive desalination capacity of 120.8 mg g−1 (2.06 mmol g−1 Na+) with a fast average desalination rate of 0.25 mg g−1 s−1 (0.004 mmol g−1 s−1) at 1.2 V, competitive with those reported in the literature. Moreover, the elucidation of the structure‐performance correlation provides valuable insights for the development and design of next‐generation PBAs for capacitive deionization (CDI). [ABSTRACT FROM AUTHOR]

Recently it was found that doped barium stannates have proton conductivity and can be used for various electrochemical applications. In this study, we investigated the effect of lutetium doping of the tin sublattice on the functional performance of oxides BaSn 1-х Lu х O 3 (х = 0, 0.05, 0.1, 0.15). Oxides with the concentration of lutetium up to 10% mol. were found to be single-phase, crystallizing in a cubic structure with a space group Pm 3 m. The lattice parameter increases linearly with the concentration of lutetium. The oxide with 15 % mol. of lutetium contains an additional phase of Lu 2 Sn 2 O 7. Electrical conductivity of the oxides was studied by the 4-probe DC method and impedance spectroscopy. Experiments were carried out in H 2 O and D 2 O - containing air atmospheres, as well as under dry air conditions. It was found that electrical conductivity of BaSnO 3 does not depend on humidity, while for Lu-doped oxides tends to decrease with increase in the humidity. Impedance data analysis has shown that change in the humidity mostly affects the grain boundary resistance. It is shown for the first time that the conductivity of BaSn 1-х Lu х O 3-δ in D 2 O-containing air is higher than in H 2 O-containing air, which was explained by the thermodynamic isotope effect. [ABSTRACT FROM AUTHOR]

In this study, the WIEN2k code, utilizing the full potential linearized augmented plane wave (FPLAPW) approach within the framework of density functional theory (DFT), explicitly employing the PBEsol approximation, is employed to investigate the fundamental properties of W-doped and (Mo, W) co-doped cubic CeO2. Herein, lattice constants, bulk modulus and cell volumes were evaluated for structural properties. The total density of states (TDOS) for various doped and co-doped CeO2 systems was used to explain the origin of magnetic behavior. The band structure (BS) calculations show that the doped and co-doped materials exhibit semiconductor behavior with a direct bandgap in both spin channels. The calculated total spin magnetic moments of W/CeO2 and (Mo, W)/CeO2 alloys are 2.002 μ B and 4.007 μ B , respectively. Furthermore, the optical absorption shows absorption peaks in the visible range and a redshift. As a result, adding molybdenum and tungsten additives improves the electro-optical properties of previous materials. [ABSTRACT FROM AUTHOR]

The anomalous Hall effect (AHE), a hallmark of broken time–reversal symmetry, serves as a powerful tool for probing magnetic states and elucidating complex spin–orbit interactions in transition metal oxides. It is reported here that the emergence of AHE signals and interfacial ferromagnetism is directly observed from broken–symmetry integrated perovskite PrCoO3 and brownmillerite SrCoO2.5 superlattices. Through the strategic combinations of these two complex oxide systems onto the substrates with tailored lattice parameters, squared AHE hysteresis loops with perpendicular magnetic anisotropy are found under compressive strain in the optimized superlattices, and the magnitude of the loops is more than three times greater compared to those under tensile strain. The manifestation of AHE in these superlattices is attributed to an extrinsic mechanism involving spin–polarized scattering of charge carriers, with the mismatched perovskite/brownmillerite interfaces acting as the primary scattering centers. These discoveries suggest a promising avenue for the development of artificial materials with controllable AHE properties. [ABSTRACT FROM AUTHOR]

Ferroic materials enable a multitude of emerging applications, and optimum functional properties are achieved when ferromagnetic and ferroelectric properties are coupled to a first‐order ferroelastic transition. In bulk materials, this first‐order transition involves an invariant habit plane, connecting coexisting phases: austenite and martensite. Theory predicts that this plane should converge to a line in thin films, but experimental evidence is missing. Here, the martensitic and magnetic microstructure of a freestanding epitaxial magnetic shape memory film is analyzed. It is shown that the martensite microstructure is determined by an invariant line constraint using lattice parameters of both phases as the only input. This line constraint explains most of the observable features, which differ fundamentally from bulk and constrained films. Furthermore, this finite‐size effect creates a remarkable checkerboard magnetic domain pattern through multiferroic coupling. The findings highlight the decisive role of finite‐size effects in multiferroics. [ABSTRACT FROM AUTHOR]

Using first principles calculations, the hydrogen storage, mechanical, dynamic, thermodynamic, electronic and optical properties of YCrH 3 (Y = Ca, Sr, Ba) materials are studied for the first time. The lattice constants of CaCrH 3 , SrCrH 3 and BaCrH 3 are 3.70, 3.88 and 4.07 Å, respectively. Exploration of the mechanical properties shows that both CaCrH 3 and BaCrH 3 are brittle, whereas SrCrH 3 is ductile. In addition, all compounds are metallic, thus facilitating efficient charge transfer during hydrogen storage and release. According to the Bader partial net charges, the charge transfer in the YCrH 3 materials is analyzed. The electron density distributions show that the CaCrH 3 hydride contains ionic and covalent bonds, whereas SrCrH 3 and BaCrH 3 are ionic hydrides. Studies of optical properties reveal that CaCrH 3 has the largest static refractive index and dielectric constant. Notably, all the studied hydrides exhibit dynamic, thermodynamic and mechanical stability. The gravimetric hydrogen storage capacities are 3.08, 2.08 and 1.55 wt% for CaCrH 3 , SrCrH 3 and BaCrH 3 , respectively. These investigations provide an important theoretical basis for further exploring the application of hydride materials in the field of hydrogen storage. [ABSTRACT FROM AUTHOR]

For an ordinary ferroelectric, the magnitude of the spontaneous electric polarization is at least one order of magnitude smaller than that resulting from the ionic displacement of the lattice vectors, and the direction of the spontaneous electric polarization is determined by the point group of the ferroelectric. Here, we introduce a new class of ferroelectricity termed Fractional Quantum Ferroelectricity. Unlike ordinary ferroelectrics, the polarization of Fractional Quantum Ferroelectricity arises from substantial atomic displacements that are comparable to lattice constants. Applying group theory analysis, we identify 27 potential point groups that can realize Fractional Quantum Ferroelectricity, including both polar and non-polar groups. The direction of polarization in Fractional Quantum Ferroelectricity is found to always contradict with the symmetry of the "polar" phase, which violates Neumann's principle, challenging conventional symmetry-based knowledge. Through the Fractional Quantum Ferroelectricity theory and density functional calculations, we not only explain the puzzling experimentally observed in-plane polarization of monolayer α-In2Se3, but also predict polarization in a cubic compound of AgBr. Our findings unveil a new realm of ferroelectric behavior, expanding the understanding and application of these materials beyond the limits of traditional ferroelectrics. A concept of fractional quantum ferroelectricity is proposed, where the direction of ferroelectric polarization difference no longer subjects to the symmetry restrictions of Neumann's principle. It indicates that ferroelectricity can exist in nonpolar systems, which may lead to discovery of many overlooked ferroelectrics. [ABSTRACT FROM AUTHOR]

High-entropy carbides (HECs), which exhibit a unique combination of properties that render them suitable for a variety of applications, have garnered significant interest. The role of vacancies in HECs, critical to their performance, remains insufficiently explored. This investigation delves into the stability, mechanical characteristics, electronic properties, and thermodynamic features of rock salt-structured (HfTaZrNb)C1-x (x = 0.0, 0.125, 0.25, 0.375), employing density functional theory and the Debye–Grüneisen model. Our findings confirm the thermodynamic stability of (HfTaZrNb)C1-x, as indicated by negative formation energies. Increasing vacancy content results in a decrease in lattice constants, modulus, hardness, and minimum thermal conductivity, alongside a reduction in elastic anisotropy and Debye temperature. Conversely, ductility is enhanced. Electronically, the research provides detailed insights into how vacancies influence bonding, elucidating the underlying reasons for variations in mechanical properties. This study deepens our understanding of vacancy impacts at the atomic level in HECs, providing vital data to inform future material design and application strategies. [ABSTRACT FROM AUTHOR]

The growth of InAs on a GaAs (001) substrate follows the Stranski–Krastanov (S–K) growth mode. Initially, the stress due to the lattice constant difference is small, resulting in two-dimensional growth. However, as the thickness of the growth layer increases, this stress accumulates, and upon reaching a critical film thickness, the growth transitions to three-dimensional, facilitating stress relaxation. Strain changes during crystal growth can be observed through variations in substrate curvature. However, in InAs/GaAs quantum dots (QDs), these changes are minimal, making observation challenging. Previously, the curvature of the substrate during InAs/GaAs QD formation could only be estimated with low precision, necessitating the use of very thin substrates with cantilever structures to achieve higher curvature. In this study, we applied the magnification inferred curvature (MIC) method, which allows for high-precision estimation of substrate curvature during molecular beam epitaxy growth. This method enabled us to observe strain changes during the formation and relaxation processes of QDs on standard-thickness GaAs (001) substrates. The results highlight the potential of the MIC method in investigating the complex interplay of strain and stress in semiconductor growth processes, emphasizing its suitability for fabricating next-generation QD devices. [ABSTRACT FROM AUTHOR]