Lattice Parameters Research Articles

Influence of Mg+2 on the structure, microstructure, and magnetic interactions of zinc ferrite nanoparticles synthesized via co-precipitation route

Evolution of the structural, morphological and magnetic properties of Zn1-xMgxFe2O4 (X = 0.00, 0.10 and 0.20) nanoparticles are discussed in detail and relation between cation disorder and magnetic interactions are prospected. The synthesized samples sintered at 500 °C temperature under examination display cubic crystal structure possesses Fd-3m as space group. The average crystallite size and lattice parameter shows variation as revealed from scherrer equation with the addition of Mg dopant at zinc site. Rietveld refinement presented single phase formation. Raman spectroscopy was utilized to convey different Raman modes and their associated vibrations. Scanning electron microscopy was utilized to survey the morphological attributes. Magnetization studies reveal weak ferromagnetism at low temperature (5 K) due to cation disorder for all samples. Zero field cooled and field cooled curves from magnetization vs temperature reveal the blocking temperature and its dependence on cation disorder and particle size. These results provide information about the possible applications of zinc ferrite nanoparticles in magnetic sensors, nanomedicine, optoelectronics, and memory devices.

Colorimetric IPN hydrogels embedded with colloidal photonic crystals: A novel approach for the detection of ethanol and Ba2+ ions in water

A critical bottleneck in sensor technology is the rapid and precise detection of specific analytes in complex matrices, hindering advancements in environmental monitoring, healthcare, and industrial process control. This study addresses this challenge by introducing a novel composite hydrogel sensor designed for rapid and selective detection of ethanol and barium ions (Ba2+) in aqueous environments. The sensor integrates interpenetrating network (IPN) hydrogels with embedded colloidal photonic crystals (CPCs), synthesized via a solution-based polymerization approach. This innovative configuration allows CPCs to dynamically adjust their photonic bandgap in response to environmental changes, manifesting as a visible, colorimetric shift. This response stems from the synergy between the mechanical properties of the IPN hydrogel and the optical sensitivity of CPCs. Upon exposure to analytes such as ethanol and Ba2+, the sensor exhibits a rapid and reversible color transition that is directly proportional to their concentration. Notably, ethanol (0 vol%–80 vol%) and Ba2+ (5–17.5 mM) induce a distinct blueshift in the photonic bandgap and trigger a color change from red–orange to green due to the alteration in the swelling behavior of the IPN hydrogel, affecting its lattice constant. The IPN hydrogel–CPC composite demonstrates exceptional operational stability and facilitates rapid detection, making it ideal for on-site applications without the need for complex equipment. These characteristics make the composite hydrogel sensor a promising candidate for environmental monitoring, industrial process control, and public health diagnostics, paving the way for the development of next-generation responsive sensor materials.

The effect of vanadium on the magnetic and mechanical properties of B2 FeCo alloy: a DFT approach

FeCo alloys play an important role in soft magnetic materials with a wide range of technological applications due to their high saturation magnetization and Curie temperature. However, these alloys have low ductility at room temperature. The ductility can be improved by the ternary addition of elements such as V. A density functional theory supercell approach was used to generate B2 Fe50Co50-xVx (0 < x < 50) structures and the properties were evaluated at different atomic percentage compositions to determine the ductility at room temperature. The structures were fully optimized to obtain better equilibrium ground-state properties such as lattice parameters and thermodynamic properties for both binary and ternary systems. The stability of Fe50Co50-xVx was evaluated from the heats of formation, elastic properties, and phonon dispersion curves. Furthermore, magnetic strength was evaluated from magnetic moments. It was found that all structures are thermodynamically stable due to the negative heats of formation. The calculated Pugh's ratio and Poisson's ratio confirm that alloying with V effectively improved the ductility. It was also found that Fe50Co50-xVx showed a positive shear modulus for the entire concentration range investigated, in agreement with phonon dispersion curves. The ternary addition of V to the FeCo system resulted in reduced magnetic strength due to a decrease in magnetic moments. These findings reveal that B2 FeCo-V alloys can be used as components and actuators for the automotive industry.

Fabrication, structure, and physical properties of three-B-site perovskite Ba(Zr1–2xTixCex)O3

In this study, three-B-site perovskite Ba(Zr1–2xTixCex)O3 (x=0–0.2) materials with the co-substitution of Ti4+ and Ce4+ at the Zr-site of barium zirconate (BaZrO3) were successfully prepared. The analyses of XRD & Rietveld method, SEM, and TEM indicated that the substituted ions Ti4+ and Ce4+ entered the BaZrO3 lattice to form a single-phase solid solution, showing a conventional primitive cubic perovskite structure (Pm-3 m space group), and its lattice parameters gradually increased from 0.4192 nm to 0.4206 nm with x value. The sample with x=0.1 exhibited relatively optimal structural uniformity and densification, as well as comprehensive physical properties. The sample Ba(Zr0.8Ti0.1Ce0.1)O3 showed a minimum mean grain size of 1.50 μm. And due to the combined effect of solid solution formation and grain refinement, it displayed an apparent porosity of 1.42 % with a cold modulus of rupture (CMOR) of 123.8 MPa, and a thermal conductivity at ambient temperature of 2.197 W/mK. Furthermore, this three-B-site perovskite Ba(Zr1–2xTixCex)O3 exhibits excellent high-temperature stability. This study demonstrates the promising application of the dense, high-strength, and low-thermal conductivity Ba(Zr0.8Ti0.1Ce0.1)O3 perovskite material in the field of advanced refractory ceramics.

A comparative study of structural, elastic, electronic, thermophysical, and optical properties of cubic binary lave-phase intermetallic compounds of HfX2 (X = cr, mo, and W): An ab initio insight

In the present work, we have made a comparative investigation on the structural, elastic, electronic, thermos-physical, and optical properties of cubic binary lave phase intermetallic compound with the common formula HfX2 (X = Cr, Mo and W) based on Density Functional Theory (DFT) using CASTEP. The result of geometrical optimization has been strongly agreed with the experimental results. The HfW2 compound exhibits larger lattice parameters and volumes than HfMo2 and HfCr2 because of the variation of atomic radii of the exhibiting elements in the studied compounds. The elastic properties show that each of the compounds in the ground state is mechanically stable and has a highly ductile nature. Band structures and energy densities of states have been studied to learn more about electronic properties. These compounds display metallic properties in their electrical band structures. They also have high machinability, a low Debye temperature, low bond hardness, and a remarkably high melting point. Our investigation thoroughly examined the reflectivity, absorption coefficient, refractive index, dielectric function, optical conductivity, and loss function of these metals. The optical absorption, reflectivity spectra, and refractive index of HfX2 (X = Cr, Mo, and W) indicate their potential for use as solar reflectors in the IR-Vis region and UV–Vis absorbers.

DFT study of optoelectronic and thermoelectric properties of pure and doped double perovskite Cs2SnI6 for solar cell applications

The global need of energy is raising day by day. To meet this demand double perovskites (DPs) can play a vital role for energy conversion devices. In this letter, we formulated and examined lead-free defect perovskites using a combination of tellurium and tin, denoted as Cs2Sn1-xTexI6 (0, 0.25), utilizing density functional theory which include structural, optical and thermal behavior. Both the optimized volume and lattice parameter exhibit a linear increase with the Te content in Cs2Sn1-xTexI6 (CsSnTeI). The negative value of formation energy for both pure and doped materials along with their Poisson and Pugh ratio confirm the stability of these materials. The band structure analysis reveals its semiconducting behavior, with the band gap expanding proportionally to the increased Te concentration with band gap value of pure (1.20 eV) and doped 91.43 eV) double perovskites. Optical characteristics, including the dielectric function and absorption coefficient, were also analyzed. To expose their potential use of Cs2Sn1-xTexI6 (0, 0.25) in thermoelectric devices, temperature dependent thermoelectric features are investigated reveal that suitability of these materials for energy conversion purposes.

Light-trapping by wave interference in intermediate-thickness silicon solar cells

The power conversion efficiency of crystalline silicon (c − Si) solar cells have witnessed a 2.1% increase over the last 25 years due to improved carrier transport. Recently, the conversion efficiency of c − Si cell has reached 27.1% but falls well below the Shockley-Queisser limit as well as the statistical ray-optics based 29.43% limit. Further improvement of conversion efficiency requires reconsideration of traditional ray-trapping strategies for sunlight absorption. Wave-interference based light-trapping in photonic crystals (PhC) provides the opportunity to break the ray-optics based 4n 2 limit and offers the possibility of conversion efficiencies beyond 29.43% in c − Si cells. Using finite difference time domain simulations of Maxwell’s equations, we demonstrate photo-current densities above the 4n 2 limit in 50 − 300µm-thick inverted pyramid silicon PhCs, with lattice constant 3.1µm. Our 150µm-thick PhC design yields a maximum achievable photo-current density (MAPD) of 45.22mA/cm 2. We consider anti-reflection coatings and surface passivation consisting of SiO 2 − SiN x − Al 2 O 3 stacks. Our design optimization shows that a 80 − 120 − 150nm stack leads to slightly better solar light trapping in photonic crystal cells with thicknesses <50µm, whereas the 80 − 40 − 20nm stack performs better for cells with thicknesses >100µm. We show that replacing SiN x with SiC may improve the MAPD for PhC cells thinner than 100µm. For a fixed lattice constant of 3.1µm, we find no significant improvement in the solar absorption for 50 and 100µm-thick cells relative to a 15µm cell. A substantial improvement in the MAPD is observed for the 150µm cell, but there is practically no improvement in the solar light absorption beyond 150µm thickness.

Van der Waals mid-wavelength infrared detector linear array for room temperature passive imaging.

Passive imaging for mid-wave infrared (MWIR) is resistant to atmospheric pollutants, guaranteeing image clarity and accuracy. Arrayed photodetectors can simultaneously perform radiation sensing to improve efficiency. Room temperature van der Waals (vdWs) photodetectors without lattice matching have evolved rapidly with optimized stacking methods, primarily for single-pixel devices. The urgent need to implement arrayed devices aligns with practical demands. Here, we present an 8 by 1 black phosphorus/molybdenum sulfide (BP/MoS2) vdWs photodetector linear array with a fill-factor of ~77%, fabricated using a temperature-assisted sloping transfer method. The flat interface and uniform thickness facilitate carrier transport and minimize pixel nonuniformities, showing an average peak detectivity (D*) of 2.34 × 109 cm·Hz1/2·W-1 in the mid-wave infrared region. Compared to a single pixel, push-broom scanning passive imaging is eight times more efficient and further enhanced through mean filtering and fast Fourier transform filtering for strip noise correction. Our study offers guidance on vdWs arrayed devices for engineering applications.

Synthesis and characterization of cubic δ–phase stabilized Bi2O3 electrolytes by triple rare earth cation doping for intermediate temperatures SOFCs

Face–centered cubic–Bi2O3 (δ–phase), a high–ion conductor, is an essential solid electrolyte option, particularly for low–low–temperature SOFC applications. It is widely accepted that δ–Bi2O3 exhibits higher conductivity than the YSZ electrolytes typically utilized in HT–SOFC units. The present study investigates the structural, thermal, surface, and conductivity characteristics of the Bi2O3 electrolytes co–doped with Tb–Sm–Gd rare earth. The XRD data indicate that, except composition 20Tb20Sm20Gd, all compositions are stabilized with the cubic δ–phase at room temperature. The estimated lattice constants additionally suggest lattice contraction, confirming that the partial cation substitutes between host Bi3+ and rare earth cations are successful. The DTA curves do not have any endothermic or exothermic peaks, indicating a possible phase transition. Arrhenius plots prove that DC conductivity decreases as the dopant ratio increases, implying a drop in polarization power. The highest conductivity is found to be 0.131 S/cm for the composition 10Tb10Sm10Gd.

Flux Crystal Growth, Structure, and Optical Properties of LiLa3Ti2S3O6: An Oxysulfide Phase Derived from K2NiF4-Type Structure.

Single crystals of a new titanium oxysulfide, LiLa3Ti2S3O6, were grown from a KI molten salt. Single-crystal X-ray diffraction analysis revealed that LiLa3Ti2S3O6 crystallizes in the space group Pnma with lattice parameters of a = 11.7319(4) Å, b = 3.94787(14) Å, and c = 20.6885(6) Å. In this structure, the one-dimensional chains of corner-sharing TiO5S octahedra are further corner-linked via equatorial and apical oxygen atoms to form unique corrugated two-dimensional perovskite-type layers in the ab plane with one octahedral thickness. These layers were intervened along the c-axis by the LaS rock-salt layers corrugated concomitantly with the perovskite-type layers, and LiO2S2 tetrahedral chains were located between these two types of two-dimensional layers. LiLa3Ti2S3O6 can be viewed as a modified K2NiF4-type structure with TiO5S octahedral layers stacked in a zigzag manner along the c axis. The oxysulfide has a direct-type band gap of 1.85 eV, based on UV-vis-NIR diffuse reflectance measurements. First-principles calculations showed that the conduction band minimum mainly consists of Ti 3d orbitals, and the valence band maximum consists of S 3p, O 2p, and Li 2s orbitals. The electronic structures near the Fermi level are similar to those of the structurally related photocatalytic oxysulfides Y2Ti2S2O5 and La5Ti2CuS5O7.

Tailoring the geometry of visible and near-infrared light active CuSe nanostructure for enhanced photocatalytic activity

Semiconductor photocatalysts play a pivotal role in fostering a sustainable environment by harnessing solar energy directly into chemical energy to achieve various photocatalytic processes. Therefore, a visible-infrared active photocatalyst is the next level of demand for solving the alarming environmental issues. In this regard, the present article reports the investigations of crucial mechanisms and conditions leading to pure and defect-free hexagonal 2D CuSe nanosheets (NSs) and the influence of their structural architecture on visible-infrared active photocatalytic performance. Here, it was achieved by the conventional hydrothermal method by varying the pH of the reaction mixture. XRD analysis was used to examine the crystal structure and lattice parameters of CuSe NSs. The presence of H+ ions was suggested to significantly influence the observed anisotropic crystallite growth across different pH conditions. EDS and XPS analysis exhibited the purity and stoichiometry of 2D CuSe NSs, revealing that the obtained stoichiometry was consistent with CuSe composition. The morphological characteristics were investigated using FE-SEM as well as HR-TEM analyses, and the specific surface area was determined using Brunauer-Emmett-Teller analysis in which a significant change occurred in response to the variation in reaction conditions. The optical properties of optimized 2D CuSe NSs show excellent absorption in the visible and near-infrared region utilizing full solar with a notable decrease in emission intensity, suggesting a reduction in recombination rates due to pH-induced changes in the nanoarchitecture. Herein, methylene blue, a well-established model dye, was used as a probe to assess the photocatalytic activity of the synthesized CuSe NSs. Notably, the CuSe NSs synthesized under neutral conditions demonstrate a remarkable methylene blue degradation efficiency, reaching approximately 98 % within approximately 45 minutes, indicating a high degradation rate. Finally, an in-depth exploration into the intricacies of photocatalytic performance, degradation mechanisms, and the recyclability test was conducted, accompanied by a thorough investigation into the feasibility of CuSe NSs for their practical application in photocatalytic wastewater treatment.

First principles study of structural and optoelectronic properties of semiconductor NaBeP[formula omitted]N[formula omitted] alloys for photovoltaic applications

In this paper, the structural and optoelectronic properties of semiconductor NaBePxN1−x (x=0,0.25,0.50,0.75 and 1) alloys in the half-Heusler structure were investigated using density functional theory with GGA approximation. The lattice parameter a, the formation energy Ef and the cohesive energy Ec were examined. The obtained results show that the lattice parameter as a function of x for NaBePxN1−x alloys obeys Vegard’s Law. The negative values of Ef and Ec indicate that NaBeN and NaBeP alloys have thermodynamic stability and strong chemical bonds, implying that they could be synthesized in future experimental research. The estimated optical properties revealed details for NaBePxN1−x alloys concerning the optoelectronic and photovoltaic applications. The high absorption (α(x=0,1)≈1.6×106cm−1) and reflectivity coefficients (R(x=0,1)>55%), indicate their suitability for usage in optoelectronic devices. The promising power conversion efficiency (η≈15%) also predicts that the thermodynamically stable alloys NaBeN and NaBeP are good for solar cell applications.

Effect of Dy3+ ion doping on magnetothermal and dielectric properties of GdCrO3

In this paper, the crystal structure, vacancies, magnetoelectric properties and magneto-thermal properties of Gd1-xDyxCrO3(0 ≤ x ≤ 0.5) samples were reported. In crystal structure analysis, after doping Dy3+, the lattice constant and the grain size of the sample decreases. The results of positron annihilation lifetime study indicates that the overall electron density near defect increases and that appeared as a gradual decreasing trend of τ2 with Dy3+ concentration. The ferromagnetism of the sample gradually decreased after doping, and the TN(Cr) of the sample decreased systematically with increasing concentration of Dy3+. Moreover, the introduction of Dy3+ inhibited the magneto-electric coupling and weakened the magneto-thermal properties of the samples. This result reveals the effect of Dy3+ doping on the structure, magnetic properties, magnetothermal and dielectric properties of GdCrO3.

Growth, Characterizations of Oxalic Acid Di-Hydrate Crystals of Pure, Milled, Shocked Impact of 50 Scaling for Electronic, Photonic, Display and Sensor Usefulness by Theory and Practice

Oxalic acid dihydrate (OADH) crystal was grown by slow evaporation solution method, milled to micro-OADH, impacted with shocked 50 pulses and harvested in a 16-day period. The 2 MPa pressure with 2.2 Mach number of 864 K temperature specifies the product as shocked 50 scaled OADH. Single crystalline X-ray diffraction of OADH macro are as specified with P21/n as space group with monoclinic as the crystal system and shocked 50 scaled OADH are with lattice constants; the % of elements of OADH specimen are confirmed by theory and practice. The dielectric constant of OADH is higher at lower frequency values by space charge polarization. OADH of all scales are of the negative photo-conductivity type. The influx data of OADH of three types of scaling are identified as better electronic filter. The micro-OADH is confirmed by the scanning electron microscopy analysis as 10 micrometer scaling without any flaws. The Fluorescence (FL) study shows bluish FL emission for all samples of OADH; sensitivity is 8.88>6.6>2.2 for shocked 50-OADH, micro-OADH, macro-OADH. The Miller’s indices of (101) profile for RGB display is shown without as well with recursive colors of OADH.

Computational study of LiAlSi, LiAlGe and LiGaSi Half-Heusler alloys for opto-electronic applications

In this comprehensive investigation, the structural, elastic, electronic, optical, thermodynamic and thermoelectric properties of Lithium-based ternary semiconductors, namely LiAlGe, LiAlSi, and LiGaSi were explored. Utilizing first-principle calculations, various material properties were accurately determined . The lattice constants, bulk modulus, and equilibrium total energies were obtained revealing that the three alloys are mechanically stable and show brittle behavior. Electronic band structures and density of states calculations, employing PBE+U, unveiled band gaps of 1.32 eV, 1.55 eV, and 1.47 eV for LiAlGe, LiAlSi, and LiGaSi, respectively, suggesting their suitability for photovoltaic applications. Analysis of the absorption spectra allowed the identification of the active window of the electromagnetic spectrum for these materials. Subsequently, the materials exhibited desirable optical properties, characterized by efficient optical absorption, with the highest peaks in the visible light and ultraviolet regions of the electromagnetic spectrum, low reflectivity, and a high dielectric constant. These collective findings indicate the potential of these materials for application in the field of opto-electronics. Furthermore, calculations of thermoelectric properties disclosed figure of merit values of 0.830, 1.046, and 0.697 at 950 K for the LiGaSi, LiAlSi, and LiAlGe HH alloys, respectively, further highlighting their potential for use in thermoelectric applications.

Tailoring Structural and Magnetic Properties: Cd²⁺ and Cu²⁺ Co-Doped Ni-Zn Ferrite Nanoparticles via Sol-Gel Auto-Combustion

In this research work, we have incorporated paramagnetic Cu2+ and diamagnetic Cd2+ cations in spinel ferrites. By adjusting the concentrations of Cu and Cd, it is possible to achieve a balance between enhanced electrical conductivity, desired magnetic properties, and suitable structural characteristics for applications in high-frequency devices, magnetic sensors, and electromagnetic interference (EMI) suppression through a synergistic effect. The sol-gel auto-combustion method was employed to synthesize Cd²⁺ and Cu²⁺ co-doped Ni₀.₅Zn₀.₅₋ₓ₋ᵧCuₓCdᵧFe₂O₄ (x = y = 0.0, 0.05, 0.1, 0.15, 0.2) ferrite nanoparticles. Structural, morphological-compositional, functional, and magnetic properties of the nanoparticles were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy with energy dispersive spectroscopy (FESEM-EDS), Fourier-transform infrared spectroscopy (FT-IR), and vibrating sample magnetometry (VSM). The XRD results confirmed the single-phase spinel structures with lattice constants increasing with higher dopant concentrations. The average crystallite sizes were found in the range of 38.14 - 42.68 nm and lattice constants in the range of 8.389 - 8.423 Å. Morphological analysis revealed agglomeration, consistent with the stoichiometric proportions during synthesis. There is a decreasing trend in nanograin sizes in the range of 40 to 73 nm with the concentration. FT-IR spectra verified the spinel structures through characteristic absorption bands around 600 cm⁻¹ and 400 cm⁻¹. Magnetic measurements indicated a decrease in saturation magnetization with increasing dopant levels indicating their potential use in electromagnetic wave absorption and magnetic memory devices.

Physicochemical, morphological, and charge carrier mobility range dielectric evaluations of Yb-doped BaCo2 W-type hexagonal ferrites for high-frequency applications

Microwave absorption materials have attracted attention due to their extensive applications in different fields. Herein, ytterbium-doped BaCo2 W-type hexaferrite nanocrystallites with a nominal composition of BaCo2YbxFe16−xO27 (x = 0.00, 0.03, 0.06, 0.09, and 0.12) were synthesized via the sol–gel method, and their physicochemical and dielectric characteristics were estimated. XRD plots revealed the pure phase structure of each prepared hexaferrite sample. The lattice constant and unit cell volume were affected by changes in the Yb concentration. The crystallite size was measured by the Debye–Scherrer formula, revealing intense crystals typically in the 18–33 nm range. FTIR spectroscopy showed multiple absorption bands from 430 to 3000 cm-1, and Raman spectroscopy revealed multiple peaks between 200 and 1000 cm-1, displaying the allocated polyhedra and symmetry. XPS spectroscopy confirmed the existence of all metal ions in the required valence state. The dielectric measurements were evaluated at frequencies from 1–6 GHz for all the synthesized compositions, and the material behavior was explained using the Maxwell–Wagner and Koop theories. The conduction mechanism in the hexagonal ferrites was assessed using Cole–Cole analysis. Reflection loss measurements were also conducted: the samples at x = 0.03 and x = 0.12 yielded minimal reflection losses of -60.06 and -51.69 dB at 5.5 GHz, respectively. The results demonstrate the suitability of the samples for use in microwave and high-frequency absorption applications.

Small polaron hopping and tunneling mechanisms in Ba0.9La0.1Fe12O19 hexaferrite ceramic at low temperatures

The correlation between dielectric relaxation and conduction mechanisms in the Ba0.9La0.1Fe12O19 ceramic hexaferrite, at temperatures below 100 K was investigated. The sample was prepared using the conventional solid-state reaction method. X-ray diffraction analysis indicated that the sample is composed of a hexagonal BaFe12O19 phase (lattice parameters a = 5.8778(6) Å and c = 23.170(3) Å) and a small proportion of hematite (α-Fe2O3). The average grain size is 1.48 ± 0.4 μm, with irregular hexagonal and agglomerated grains. The magnetic hysteresis curve shows characteristics typical of ferro and ferrimagnetic materials, with an effective magnetic anisotropy coefficient of 0.960×106 emu/cm3 and an anisotropy field of 1.587×104 Oe. A dielectric relaxation process is observed between 50 and 100 K, with an activation energy of 60.4 ± 0.4 meV and a characteristic relaxation time of 2.09 ×10−10 s, mainly attributed to the electrical behavior of the grains. Two conduction mechanisms were identified: small polaron tunneling (high temperatures and low frequencies) and correlated barrier hopping of electrons (low temperatures and high frequencies). The activation energy for free polaron formation, according to the Komine-Iguchi hopping polarization model, was 7.12 ± 0.02 meV. In the dielectric modulus relaxation process between 30 and 54 K, the activation energy was 40.8 ± 0.9 meV, with a characteristic relaxation time of 2.41×10−10 s. The small polaron conductivity in the grain region was 67.52 meV and 54.0 meV in the grain boundary region. The results highlight that the polarization and conduction mechanisms in this ceramic at low temperatures are dominated by small polaron hopping and tunneling, and emphasize the influence of La3+ doping on the structural, magnetic, and electrical properties of barium hexaferrite.

Universality in the Structure and Dynamics of Water under Lipidic Mesophase Soft Nanoconfinement.

Water under soft nanoconfinement features physical and chemical properties fundamentally different from bulk water; yet, the multitude and specificity of confining systems and geometries mask any of its potentially universal traits. Here, we advance in this quest by resorting to lipidic mesophases as an ideal nanoconfinement system, allowing inspecting the behavior of water under systematic changes in the topological and geometrical properties of the confining medium, without altering the chemical nature of the interfaces. By combining Terahertz absorption spectroscopy experiments and molecular dynamics simulations, we unveil the presence of universal laws governing the physics of nanoconfined water, recapitulating the data collected at varying levels of hydration and nanoconfinement topologies. This geometry-independent universality is evidenced by the existence of master curves characterizing both the structure and dynamics of simulated water as a function of the distance from the lipid-water interface. Based on our theoretical findings, we predict a parameter-free law describing the amount of interfacial water against the structural dimension of the system (i.e., the lattice parameter), which captures both the experimental and numerical results within the same curve, without any fitting. Our results offer insight into the fundamental physics of water under soft nanoconfinement and provide a practical tool for accurately estimating the amount of nonbulk water based on structural experimental data.

Structural, Optical, and Dielectric Properties of Co0.6Mn0.4GdxFe2-xO4 ferrites prepared through Sonochemical Method

Gadolinium-substituted cobalt manganese ferrite nanoparticles with the composition Co0.6Mn0.4GdxFe2-xO4 (where x ranges from 0.0 to 0.08, with x = 0.02) were prepared through the sonochemical method. X-ray diffraction reveals that grown samples are single-phase cubic spinel belonging to space group Fd3m, where the crystallite sizes decrease with increasing Gd3+ content. At high doping ratios (x > 0.06), there was a slight increase in crystallite size compared to that of pure Co-Mn ferrite (x = 0), while the lattice parameter (a) decreased in the low doping range of Gd (x < 0.06), resulting in a reduction in crystallite size. Bertaut’s method confirms that 80% of the tetrahedral (A) sites were occupied by Mn ions, while the remaining sites were occupied by other cations in the octahedral (B) positions. Gd3+ ions were found exclusively in the octahedral-B sites. Co2+ ions were expected to occupy the octahedral-B site, which was confirmed in this study for the x = 0.0 and 0.02 samples. Field emission scanning electron microscopy shows the samples are agglomerated and have dense structures. Fourier transform infrared and Raman spectra validated the presence of spinel ferrite modes. Dielectric investigations indicate that as the Gd3+ content exceeds x = 0.0, the dielectric constant and dielectric loss decrease at lower frequencies. The observed dielectric behavior exhibited typical dispersion patterns attributed to Maxwell-Wagner polarization. Furthermore, changes in dielectric properties were observed as the Gd3+ content in Co0.6Mn0.4GdxFe2-xO4 nanoparticles increased, which can be attributed to the presence of oxygen vacancies and variations in the distribution of Fe3+ ions at both A and B-sites.