Lattice Parameter Values Research Articles

Bayesian calibration of interatomic potentials for binary alloys

Developing reliable interatomic potential models with quantified predictive accuracy is crucial for atomistic simulations. Commonly used potentials, such as those constructed through the embedded atom method (EAM), are derived from semi-empirical considerations and contain unknown parameters that must be fitted based on training data. In the present work, we investigate Bayesian calibration as a means of fitting EAM potentials for binary alloys. The Bayesian setting naturally assimilates probabilistic assertions about uncertain quantities. In this way, uncertainties about model parameters and model errors can be updated by conditioning on the training data and then carried through to prediction. We apply these techniques to investigate an EAM potential for a family of gold–copper systems in which the training data correspond to density-functional theory values for lattice parameters, mixing enthalpies, and various elastic constants. Through the use of predictive distributions, we demonstrate the limitations of the potential and highlight the importance of statistical formulations for model error.

Theoretical study of the interaction of lactose with collagen, the electronic and mechanical properties of crystalline lactose

We studied elastic and electronic properties of α- and β-lactose crystals within the framework of density functional theory with van der Waals interactions. The calculated values of lattice parameters have good agreement with the experimental data. The interaction energies of α- and β-lactose molecules with collagen protein were also calculated, which are equal to 4.2 and 4.1 kcal/mol, respectively. Complete set of elastic constants for α- and β-lactose were calculated. It has been established that mechanical properties of these crystals are different. Our calculations predict that α-lactose is ductile compound, while β-lactose is brittle compound. Topological properties of hydrogen bonds of the crystals were studied using the quantum theory of atoms in molecules (QTAIM). Thus, the differences between the α- and β-lactose molecules are manifested in the molecules interaction in the crystal resulting in the differences of macrocharacteristics of these crystals.

X-ray diffraction studies of residual strain in AlN/sapphire templates

The residual strain in the templates can significantly influence the properties of heterostructures grown on these templates and this issue cannot be neglected in e.g. LED applications. In this paper, we present an approach to determine the residual strain in AlN/sapphire templates using X-ray diffractometry at edge scans geometry. It is based on measurements carried out both: from the surface and from the edge of the sample. Edge scans allow measurements of planes perpendicular to the growth direction, which permit the unambiguous determination of the in-plane strain. This approach facilitates the characterization of AlN structures. The use of edge scans allows determining directly in-plane a lattice parameter on which the analysis is based. The reference values of the AlN lattice parameters were determined experimentally from the AlN bulk crystal.

Thermodynamic behavior of Na-majorite and knorringite-majorite garnet systems

The behavior of thermal parameters pressure (P) and thermoelastic parameters i.e. Isothermal bulk modulus (K_T), its pressure derivative (K'T) and Thermal expansivity (α) has been analyzed for Na-majorite and knorringite-majorite systems at different compressions down to a maximum value of 0.3 for temperature ranges from 300 K to 1500 K. The pressure dependent compressibility of these garnets have been studied. The comprehensive study of thermodynamic and thermoelastic behavior at different isotherms and isobars respectively has been achieved by employing both Vinet equation of state and Anderson-Isaak equation. The study of thermal expansivity (α) using Anderson-Isaak and Stacy-Davis approach shows a similar trend of MgO system. Based on the validation of Kumar's approach, the lattice parameter of garnet system is computed using Kumar and modified Kumar's approach at high temperature and is found to be very less deviated from the value of lattice parameter at room temperature.

Tuning the structural, optical and magnetic properties of NiCuZn (Ni0.4Cu0.3Zn0.3Fe2O4) spinel ferrites by Nb2O5 additive

Ni0.4Cu0.3Zn0.3Fe2O4 ferrites with various compositions (0–5 wt. %) of Nb2O5 additive were synthesized by the sol-gel method with an aim to investigate their physical properties. The analysis of Rietveld refined X-ray diffractograms confirms formation of ferrites with a single-phase spinel structure having space group Fd3m. The result indicates that there is an enhancement in the lattice parameter values with increasing Nb2O5 content. The nanoparticles in the shapes of spheres and cubes with few agglomerations were evident from field emission scanning electron microscope images of ferrites. The elemental analysis from energy dispersive X-ray spectrum confirms the stoichiometric occurrence of constituent elements within the prepared samples. The Raman spectra confirm the cubic spinel structure of the prepared ferrite samples. The Fourier transform infra-red spectra confirm the superseding of Nb5+ ions in the unit cell of NiCuZn ferrite. Oxidation states of the elements within the ferrite were confirmed by means of X-ray photoelectron spectroscopy. The UV–Visible diffused reflectance spectroscopy results show that the band gap energy values were reduced with the increasing wt.% of Nb2O5 additive in the ferrite. The Nb2O5 additive reduces the saturation magnetization and coercivity of all the ferrite samples. The study reveals that the controlled amount of Nb2O5 additive in NiCuZn ferrite can tune the soft magnetic behavior and optical parameters of the ferrite at room temperature.

FIRST-PRINCIPLES SIMULATION: STUDY OF THE STRUCTURAL, ELECTRONIC, MECHANICAL AND OPTICAL PROPERTIES OF DISULFIDE XS2 (X=Ta, Ti) COMPOUNDS FOR OPTOELECTRONIC APPLICATIONS

First-principles simulation has been performed to investigate the structural, electronic and optical properties of two disulfide compounds, i.e. [Formula: see text]S2 ([Formula: see text], Ti). The properties are examined through the density functional theory (DFT) with the implementation of Cambridge series total energy package (CASTEP) code. As regards, the structural and electronic analyses are done by Perdew–Burke–Ernzerhof-generalized gradient approximation (PBE-GGA) and hybrid Heyd–Scuseria–Ernzerhof (HSE06) functional and their results are compared herewith. The values of lattice parameters obtained through geometry optimization for TaS2 with GGA and HSE06 are [Formula: see text][Formula: see text]Å and [Formula: see text][Formula: see text]Å and [Formula: see text][Formula: see text]Å and [Formula: see text][Formula: see text]Å, respectively, while for TiS2 these parameters are found as [Formula: see text][Formula: see text]Å and [Formula: see text][Formula: see text]Å. These values are found in agreement with the experimental values. The electronic band structure, as well as density of states (DOS) of these structures, show their semiconducting nature with the direct bandgap of 1.9[Formula: see text]eV (PBE-GGA) and 2.05[Formula: see text]eV (HSE06) for TaS2 and 0.09[Formula: see text]eV (PBE-GGA) and 0.13[Formula: see text]eV (HSE06) for TiS2. The mechanical study of these compounds also has been anticipated using Voigt–Reuss–Hill approximation under the pressure range 0–30[Formula: see text]GPa to show their stability by calculating the elastic parameters, i.e. Young’s modulus, bulk and shear modulus, Poisson’s ratio, Pugh’s ratio and anisotropic factor. The analysis of optical properties divulges that TiS2 material possesses maximum absorptivity in the UV range of incident photon’s energy with minimum energy loss and decrease in reflectivity. Our comprehensive study about the considered compounds delineates them as potential candidates for technological applications in optoelectronic devices.

TI-ION IMPLANTATION EFFECTS ON THE ELECTRICAL RESISTIVITY, HARDNESS AND MICROSTRUCTURE OF BRASS ALLOY

Extensive progress in brass alloys has been done in surface properties and microstructure. Ti-ion implantation is studied for its effects on electrical resistivity, hardness and microstructure by using scanning electron microscopy, X-ray diffractometer, four-point probe apparatus and Vickers microhardness tester. Ion distribution profile and stopping powers were calculated by Stopping and Range of Ions in Matter (SRIM) code. Nonuniformity in shape, and agglomeration of defects were observed at the surface in SEM micrographs. XRD analysis of (2 0 0) plane for crystallite size, strain, stress and dislocation density is also done. The peak intensity of (2 0 0) is found to be increased by increasing the ion fluence and tensile stresses were also found generated. Increase in the lattice parameter values from 3.681 Å to 3.686 Å appeared as a change in crystallite size, which, in turn, caused an increase in hardness. An increment in electrical resistivity from 7.9[Formula: see text][Formula: see text] to 18[Formula: see text][Formula: see text] (127.85%) is also observed. For a maximum ion fluence of [Formula: see text] ions/cm2, the surface turned out to be amorphous, which helped in making the brass more reliable in its practical usage.

The impact of rare earth Nd3+ cations on structural, spectral, magnetic and dielectric parameters of NiFe2O4 nanoparticles

The co-precipitation route was used for the preparation of Nd-substituted NiFe2O4. The proposed general formula of prepared ferrite was NdxNiFe2-xO4. Here, “x” the moles of Nd3+ were 0.0, 0.0125, 0.025 and 0.05 in various compositions. The prepared nanocrystallites were characterized using X-rays diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM) and impedance analyzer. XRD patterns of all prepared samples were analyzed to confirm the phase of the materials and determine the lattice constant, crystallite size and X-rays density. The lattice parameter value varied between 8.3501 and 8.3549 Å. The average crystallite size was ∼15 nm. The FTIR spectral analysis was used to investigate the M-O stretching vibrational bands. FTIR spectra showed the stretching vibrational bands of Fe-O at octahedral and tetrahedral sites. After structural and spectral investigations, the prepared nanocrystallites were subjected to room temperature magnetic measurements by vibrating sample magnetometry (VSM) technique. The magnetic parameters were investigated from the VSM data. The magnetic parameters suggested the possible utilization of these nanocrystalline ferrites for various advanced technological applications like switching devices and high-frequency devices. The dielectric parameters were also investigated using an impedance analyzer.

Study of structural, electrical and hyperfine properties of Dy doped YFeO3

Investigations on effect of Dysprosium (Dy) on structural and electrical properties of polycrystalline Yttrium Iron Oxide (YFeO3) are presented in this paper. Y1xDyxFeO3(x = 0,0.2,0.4,0.6,0.8) samples are prepared through sol-gel process. Rietveld refined XRD plots confirms formation of mono phase orthorhombic structures. From the Rietveld data, lattice parameter values are found to increase with increase in Dy concentration. Raman spectroscopic study enables us to understand the subtle changes occurring in crystal structure due to Dy doping and also confirms the pure phase of samples. When Dy+3 is doped in place of Y+3, Raman bands are seen to be shifted to lower frequencies, which indicates an increase in lattice constants in the samples. SEM morphology investigations demonstrate that grains are not homogeneous in size and are irregular in shape. Up to x = 0.4, J-E graphs indicate a rise in leakage current density but however on further substitution of Dy, leakage current is found to decrease. From ln J vs ln E plots, it is observed that Ohmic conduction dominates the whole electric field range. Room temperature 57Fe Mössbauer studies dismiss any existence of magnetic impurities and confirm that samples have magnetic ordering.

Evaluation of the Structural Deviation of Cu/Cu2O Nanocomposite Using the X-ray Diffraction Analysis Methods

We successfully synthesized Cu/Cu2O nanocomposites using the wet chemical synthesis method. All X-ray diffraction (XRD), Reference Intensity Ratio (RIR), and Rietveld refinement methods confirmed that the compounds Cu and Cu2O are free of impurities. Scanning Electron Microscope (SEM) and Transmission electron microscopy (TEM) images show the morphology and interactions of Cu and Cu2O in the structure. The formation mechanism is also explained by five stages: precursor, nucleation, growth, aging, and reduction. The changes in crystallization parameters under variations in reaction temperature (Tv) and stirring speed (Sv) were confirmed by agreement with the XRD database. The lattice constant in the crystal of nanocomposite increases with rising temperature in the reaction, leading to unit cell expansion, while increasing the stirring—rate leads to a random size distribution of the lattice parameter. Due to the imperfect growth of the crystal, the induced crystallite size was calculated using the Williamson-Hall model, and the precise lattice parameter values were calculated using the Nelson-Riley function.

Impact of erbium (Er) doping on the structural and magnetic properties of Ni-Cu (Ni0.1Cu0.9Fe2O4) nanoferrites

Rare earth erbium (Er) doped spinel Ni-Cu nanoferrites having chemical composition Ni0.1Cu0.9ErxFe2-xO4 (x = 0.00, 0.010, 0.015, 0.020, 0.025 and 0.030) were prepared by standard citrate-gel auto combustion (CGAC) technique. X-ray diffraction spectroscopy (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), UV–visible spectroscopy, and vibrating sample magnetometer (VSM) were used to characterize the structural, optical, and magnetic properties of these ferrites. X-ray diffraction spectra clearly revealed that the pure Ni-Cu ferrite shows a tetrahedral distortion due to John Tellar ion (Cu2+) subsequently erbium doping transformed the tetragonal phase in to the cubic spinel phase with minor traces of impurity phase. Using Scherer's equation, the average crystallite size was found to be between 7.39 and 27.78 nm. The average crystallite size (7.39–27.78 nm) obtained from XRD and average grain size (64.84–83.36 nm) measured from FESEM confirmed the nano structure of prepared samples. Energy dispersive analysis X-ray (EDAX) spectra with elemental analysis verified the existence of Ni, Cu, Er, Fe, and O elements without any impurities. Two prominent absorption bands detected in FTIR spectra within the wave number range of 575.54–586.73 cm−1 (υ1) and 370.24–372.53 cm−1 (υ2) indicate the stretching vibrations of Fe3+-O2− complexes in tetrahedral and octahedral sites of spinel structure respectively. TG and DTA techniques were used to analyze the thermal behavior of the composition x = 0.030. It was observed that exhibiting a rapid loss in weight after 900 °C promotes the formation of pure phase nanoferrite. Direct and indirect optical band gap values were computed from UV absorption studies with Tauc plots. The obtained band gap values revealed the semiconducting behavior of the prepared samples. VSM was used to explore the magnetization of samples as a function of field at temperatures of 15 K and 300 K. The maximum saturation magnetization (Ms) was observed for x = 0.030 composition and it was estimated as 31.18 emu/g at 15 K and 26.80 emu/g at 300 K temperatures. The experimental and theoretical values of lattice parameter and room temperature magnetic moment are good agreement with suggested cation distribution.

Influence of neodymium doping in tuning microstructural, optical and magneto-dielectric properties of nickel ferrite nanoparticles

The present work reports the successful synthesis of pure and doped nickel ferrite (NFO) nanoparticles by a sol-gel technique using nitrates salts as precursors. A systematic investigation is done to study the impact of rare earth Neodymium (Nd) doping for modulating the microstructural, optical, electrical and magnetodielectric properties of NFO. Shifting of diffraction peaks towards higher glancing angles by Nd doping is confirmed through X-ray analysis. The Nelson-Riley extrapolation method evaluates the average value of lattice parameters. Scanning electron microscopy confirms noticeable morphological changes in doped NFO. Polycrystallinity arising in higher doping concentrations is visualized from transmission electron microscopy. Uv–visible spectroscopy demonstrates the redshift phenomenon in Nd-doped NFO due to the shrinkage of the band structure. Electric modulus and impedance studies show a higher frequency shift of relaxation peaks for doped samples. The enhancement of magnetodielectric response and the operational frequency is achieved with the effect of Nd ions doping.

Synthesize and analyze pureandmyrtaceaedopedkh2po4 crystals

Slow evaporation method at constant temperature was used to generate optically better-quality clove and pure doped Potassium Di-hydrogen Phosphate crystals, which were then characterized. If the optimum conditions are adequately attained, the slow evaporation method can be used to produce crystals with low solubility. FTIR spectra are used to assess the reality of crystal efficient groups qualitatively. To investigate the dopants effect on the ideal appearances of Potassium Di-hydrogen Phosphate, an X-ray diffraction investigation was carried out. The tetragonal design of KDP and incapacitated crystals was discovered via powdered X-ray diffraction. The lattice parameter values were determined using X-ray diffraction on a single crystal. UV-Visible spectroscopy was used to examine the generated clove doped (1:1) KDP crystals. The TG and DTA analysis were utilized to examine the constancy and breakdown of unpolluted and clove doped KDP crystals. ND-YAG laser was utilized to notice the SHG. Clove doped KDP crystals outperformed pure KDP crystals in terms of relative generation of second harmonics productivity. The effect of dopants on the exterior morphology of KDP crystals was investigated using a scanning electron microscope (SEM). EDAX was utilized to have a better understanding of the elements found in crystals.

Crystallization of dl-methionine polymorphs in the presence of structurally compatible additives

In general, amino acid additive is a key factor in controlling the crystallization of polymorphs. The effect of dl-leucine (dl-leu) on the growth mechanism of dl-methionine (dl-met) crystals was investigated under aqueous medium by varying the additive concentrations at ambient temperature. However, when the additive concentration was gradually increased, the disappearance of the prominent face of β-form (200) was observed with the emergence of (100) facets of α-form, which obviously indicates the change in the type of nucleation induced by the additive dl-leu. On the other hand, concomitant polymorphism (α and β-form) was identified at low (x = 0.001 mol/lit) additive concentration. Instead, for all other concentrations, α-form morphology was observed. Therefore, increasing the quantity of dl-leu (0.001 < x < 0.1 mol/lit) strongly influences the stability of the metastable state corresponding to α-form. Moreover, the lattice parameter values and the distinguished peaks ((600) and (113) planes) obtained from XRD analysis confirms the occurrence of α and β-form morphologies, respectively. Differential scanning calorimetry analysis indicates that the crystal undergoes a solid-state phase transformation from β form to α form. Hence, the overall premise is that addition of dl-leu to dl-met in aqueous medium is a promising technique to acquire pure α-form at ambient temperature.

Neutron-γ discrimination with organic scintillator crystal: 9-Phenylcarbazole (9-PCz) grown by Bridgman – Stockbarger method

Organic scintillator crystal 9-Phenylcarbazole (9-PCz) has been grown using Bridgman -Stockbarger technique. The crystal structure, lattice parameter and bond angle values are measured from single-crystal X-ray diffraction (SXRD) analysis. C–H inplane bending and out of plane bending and skeletal vibrations of 9-PCz molecule were identified from vibrational spectral analysis. UV–visible NIR spectral study shows that the crystal exhibits around 50% of transmittance in the infrared region and the direct optical bandgap energy is calculated to be 3.36 eV. Thermal properties of grown 9-PCz material were measured using thermogravimetric and differential thermal analyses (TG-DTA). The photoluminescence (PL) measurements show two emission bands with a maximum peak at 365 nm and a shoulder peak at 381 nm. X-ray induced luminescence spectrum of 9-PCz crystal exhibits a maximum emission peak at 381 nm. Scintillation decay time measurement shows the major component of 18 ns decay time. The pulse shape discrimination (PSD) capability of the grown crystal sample was studied for the signals induced by α-particles and γ-rays from 241Am and 137Cs sources, respectively. The figure of merit (FOM) is found to be 2.69. The preliminary results showed that the present studied organic crystal (9-PCz) scintillator can be considered in the field of fast neutron detection application.

Ab Initio Computational Details With Facile High-Temperature Synthesis of Pure and Alloyed CsPbI3 With Inherent Stability Analysis for Optoelectronic Applications

In this article, wee have performed a density functional theory-based computational experiment to gain insight into stability issues in host CsPbI <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> and attempted doping Mn as a dopant element to stabilize its phase. The obtained results throw light on various useful parameters like lattice structure, electronic band, absorption coefficient, and photoluminescence (PL). The optimized lattice parameter values of parent CsPbI <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> quantum dots (QDs) show a diminution in its value after introducing Mn on the Pb site in the crystal structure from 6.28 to 6.15 Å. This result is following the values of the lattice parameter obtained from experimentally observed X-ray diffraction (XRD) plot (6.25 to 6.15 Å) and high-resolution transmission electron microscopy (6.29 to 6.13 Å). Incorporation of Mn in parent CsPbI <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> QDs leads to phase stability, which can be seen in XRD, PL, and absorption spectra. The PL intensities can be preserved up to 30% and 80% in the case of host and Mn-alloyed CsPbI <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> QDs, respectively. The phase of host CsPbI <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> can be preserved up to five days, while the phase of Mn-alloyed CsPbI <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> QDs can be maintained up to 28 days, which can be seen in XRD plots. In addition, an increment in bandgap from 1.426 to 1.513 eV can be observed after Mn performing alloying in CsPbI <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> QDs from the theoretically calculated band structure plot, which can be further validated with the obtained bandgap values from the Tauc plot (1.76 to 1.81 eV) extracted using UV-visible spectrum.

The Effect of Y3+ Addition on Morphology, Structure, and Electrical Properties of Yttria-Stabilized Tetragonal Zirconia Dental Materials.

Zirconia (ZrO2), a widely known material with an extensive range of applications, is especially suitable for dental applications. This kind of dental material is produced in the form of blocks or discs (mostly discs—depending on CAD/CAM machines) by cold isostatic pressing (CIP). Such discs are subsequently milled by CAM/CAD technology into a desirable form. Due to the application of CIP, the resulting discs consist of different yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) powders, additives and pigments. The diverse composition of the discs (e.g., different Y3+ content) governs material properties, such as hardness, toughness and translucence. The aim of this work was to investigate the impact of Y3+ addition on the grains and grain boundaries, on the ZrO2 phases lattice parameter values and on the electrical equivalent circuit parameters of the prepared Y-TZP samples. The disc-shaped samples were prepared by using CAM/CAD technology. It was observed that the grain size and the grain density were increased by Y3+ addition. The sample with the lowest Y3+ content was characterized by the highest portion of the tetragonal phase, whilst the disc with the highest Y3+ addition consisted mainly of the cubic phase. It was also observed that at the higher Y3+ ion concentrations, these ions mainly incorporated the tetragonal phase. Furthermore, conductivity investigations showed that the resistivity of the grains in the samples with the higher Y3+ concentrations was decreased as these ions were mainly trapped in the grain boundary. On the other hand, the Y3+ trapping increased the capacitance of the grain boundary.

Superconducting properties of (Bi,Pb)2Sr2Ca2Cu3Ox (BSCCO-2223) superconductor ceramics prepared by conventional solid-state reaction and co-precipitation methods

The (Bi,Pb)2Sr2Ca2Cu3Ox (BSCCO-2223) samples were prepared by conventional solid-state reaction and co-precipitation methods. The crystal size, cell parameter, and crystal structure were identified from X-ray diffraction (XRD). The peaks drawn by co-precipitation have higher intensities and the width of peaks were narrower compared to the sample prepared by solid-state method. Slight difference in the value of lattice parameters between the samples were also noticeable. Concentration of defects increased the distortion of crystal lattice that cause the changes in these parameters. The electrical properties of the superconductors were investigated by using cryogenic four-point probe and AC susceptibility. The sample prepared by co-precipitation method was able to reach higher critical temperature, TC at 106 K compared to the other sample, TC at 97 K. Meanwhile Scanning Electron Microscope (SEM) micrographs for solid-state method sample showed more random grain alignment and porous structures. The microstructures and grain growth results of Bi-2223 were reflected to the heat and temperature applied during sintering process. In short, the research work reveals that co-precipitation method produces better quality of high temperature superconductor compared with solid-state method due to higher homogeneity resulted by chemical reactions.

Improvement of Mechanical Properties with Non-Equimolar CrNbTaVW High Entropy Alloy

CrNbTaVWx with (x = 1 and 1.7) high entropy alloys have been devised for thermal barriers between the plasma-facing tungsten tiles and the copper-based heat sink in the first wall of fusion nuclear reactors. These novel materials were prepared by ball milling and consolidated by Upgrade Field Assisted Sintering Technology at 1873 K under an applied pressure of 90 MPa for 10 min. In this work, the structural and mechanical properties of these materials were evaluated. Consolidated samples presented a major phase with a bcc-type structure with lattice parameter value of 0.316 nm for CrNbTaVW and CrNbTaVW1.7 compositions. Moreover, observation of the microstructures evidences also two minor phases: Ta-Nb-Cr and Ta-V rich (in which carbon is detected). Despite the similarity in the structural properties of these two alloys, their mechanical properties are distinct. The flexural stress for the sample with higher amount of W (CrNbTaVW1.7) is higher by 50% in the 298–873 K range, with an increased strain to fracture, which can be associated with reduced brittleness caused by the additional W incorporation.

Superparamagnetic hematite spheroids synthesis, characterization, and catalytic activity

The leaf extract of Muntingia calabura is being first reported to be used for the synthesis superparamagnetic hematite nanoparticles by following the green-chemistry approach. Field Emission – Scanning Electron Microscopic image revealed the formation of irregular nano spheroids averaging at 48.57 nm in size and characteristic of Fe and O atoms, as revealed by Energy Dispersive X-Ray spectrum. X-ray diffraction analysis results proved the crystallinity of hematite diffraction planes with crystallite sizes averaging at 30.68 nm. The lattice parameter values stayed concordant with the literature. The superparamagnetic nature was attested by the high value of saturation magnetism (2.20 emu/g) with negligible coercivity and retentivity. Fourier Transform Infrared Spectroscopy results affirmed numerous moieties involved in the synthesis of hematite nanoparticles and the existence of signature Fe–O bands. Thermogravimetric analysis studies portrayed the thermal behavior nanoparticles with 28% weight loss and thermal stability was attained after 700 °C. X-ray photoelectron spectroscopy analysis confirmed the valence states of Fe and O in the hematite nanoparticles and ascertained the purity. The mesoscopic structure was revealed by Brunauer–Emmett–Teller studies with considerable surface area (112.50 m2/g). The Fenton-like catalysis mediated by the nanoparticle sample was demonstrated by degrading methylene blue dye. The remarkable degradation efficiency of 93.44% was obtained and the kinetics was conformed to a second-order model with a high R2 value. Therefore, the highly crystalline and mesoporous superparamagnetic hematite spheroids prepared using the leaf extract of M. calabura would find promising applications in various catalysis processes.