X-ray Diffraction Patterns Research Articles

Exploring the Impact of Elevated Pressure on the Structural Dynamics of TlInS2 Crystal (I): A First-Principles Investigation with XRD, Raman, and Hirshfeld Topology

The structural dynamics of Thallium Indium Disulfide (TlInS2) crystal under elevated pressures were comprehensively investigated using a combination of X-ray diffraction (XRD), Raman spectroscopy via first-principles calculations, and Hirshfeld surface (HS) analysis. This study aims to elucidate pressure-induced modifications in the crystal structure and their associated properties of TlInS2 crystal. The findings reveal significant structural transformations as pressure increases, with XRD patterns indicating lattice compression and a critical transition from semiconductor to conductor at pressure P=6.25GPa [42]. The calculations predict a reduction in bond lengths, specifically S1-In1 and S1-Tl2, alongside a corresponding decrease in lattice parameters and unit cell volume. Raman spectroscopy corroborates these changes through shifts in phonon modes. The HS analysis provides further insights into pressure-dependent alterations in intermolecular interactions, revealing changes in voids and surface characteristics. The data gained from TlInS2's structural behavior under pressure, contributing to the optimization of its functional properties for pressure-tunable applications in high-performance electronic and optoelectronic devices.

CeO2/NH2-MIL-88B(Fe) composites with peroxidase-like activity for colorimetric detection and photo-enzymatic synergetic degradation of ciprofloxacin hydrochloride

Photocatalysis combined with enzyme catalysis for wastewater treatment is now a promising and challenging process. Therefore, it is necessary to synthesize a material with both photocatalytic and enzyme-catalyzed functions. CeO2/NH2-MIL-88B(Fe) composites with peroxidase-like activity (referred to as CNF-X, where X is the molar ratio of Ce to Fe) were prepared using a solvothermal method. The composites can be used for colorimetric detection, the limit of detection (LOD) was 0.029µM in the range of 50-200µM of ciprofloxacin hydrochloride (CIP). Using a combination of photocatalytic and enzymatic reactions, light excites enzyme activity to achieve highly efficient and selective chemical reactions. In addition, H2O2 activation promotes redox cycling reactions between Ce and Fe, providing more active sites and facilitating photo-enzymatic synergetic catalysis. Under the conditions of 0.01g CNF-5, pH = 3.5, and 25 °C, more than 92.8% of CIP (20mg/L solution) was degraded within 80min, and the photo-enzyme synergistic catalysis mechanism was examined. The stable enzymatic activity and good reusability of the material were confirmed by cycling experiments and X-ray diffraction (XRD) patterns before and after the reaction. The contribution ratio of radicals and non-radicals in the degradation of CIP was analyzed. Density functional theory (DFT) calculation was applied to predict possible degradation pathways. Simulation results stemmed from Toxicity Estimation Software Tool (T.E.S.T) showed an overall reduction in the toxicity of the intermediates. This study provides important application value and theoretical guidance for peroxidase-like materials in environmental detection and remediation.

Influence of LaMnO3 Nanocrystallite Size on its Optical and Raman Spectra

: In the current study, nanocrystalline LaMnO3 perovskite was prepared by combustion method and annealed at different annealing temperatures. The X-ray diffraction (XRD) patterns provided evidence that the structure formed has a Rhombohedral structure with R3 ̅c space group. The remarkable growth in the crystallite size, reduction in microstrain, and dislocation density were observed with annealing temperature. Ultraviolet-visible spectroscopy was used to determine the optical band gap by the Tauc-plot method. The optical band gap was found to be 3.5 ± 0.4eV and 2.9 ± 0.5eV for 600°C and 1200°C annealed samples, respectively. The observed results were influenced by crystallite size. Raman spectra of the LaMnO3 nanocrystallites revealed five Raman-active modes, like out-of-phase rotation modes and bending mode of MnO6 octahedra. Moreover, the intensity of vibrational modes also varied significantly with annealing temperature.

EFFECTS OF SYNTHESIS TEMPERATURE ON THE STRUCTURAL AND OPTICAL PROPERTIES OF CaAl2O4: Eu2+, Dy3+NANOPARTICLES

Calcium aluminate phosphor nanomaterials co-doped with europium and dysprosium (CaAl2O4: Eu2+, Dy3+) were prepared using a facile solution combustion technique. The structural and optical properties were investigated. The X-ray diffraction (XRD) results confirmed the presence of the monoclinic phase in all the samples, with few impurity phases in the samples synthesized at 300°C and 400°C. The Fourier-transform infrared analysis gave the expected chemical combustion results of the final product with few traces of Ca3Al2O6 impurities at low and very high synthesis temperatures. The XRD patterns displayed diffraction angles of the major peaks shifting to higher 2 theta as the synthesis temperature increased. This is attributed to an increase in particle sizes, which led to an increase in lattice parameters. The intensity of the prominent peak increased up to 500°C due to improved crystal quality. The crystallite sizes of the as-prepared samples were determined using the Debye-Scherrer equation. It was noted that there is variation in the crystallite sizes with synthesis temperature. The UV-Vis graph shows that absorption edges also shifted to lower wavelengths with an increase in synthesis temperature. It was noted that the band gap increased with an increase in synthesis temperature up to 500°C, but at temperature of 1000°C, the band gap was observed todecrease. Scanning electron microscope micrographs showed that the samples had irregular shapes with pores and cracks. The study provides a simple route to synthesize CaAl2O4: Eu2+, Dy3+ phosphors with optimum synthesis temperature, producing the most crystalline sample for use in lighting devices.

HTXRD based lattice thermal expansion and specific heat capacity modelling of C15-Fe2Zr Laves phase

Crystallographic phase pure C15-Fe2Zr was obtained through arc melting technique. X-ray Diffraction (XRD), scanning electron microscope (FESEM) along with energy-dispersive X-ray analysis (EDS) and differential scanning calorimetry (DSC)were employed to study the single phase in Fe-33.3at.% Zr alloy. Rietveld refinement of the high-temperature XRD patterns (from 298K-873 K) revealed the average linear and volumetric coefficients of thermal expansion of the alloys as αai= 0.3643 × 10−5 K−1 and αVi = 1.0916 × 10−5 K−1, respectively. The experimental heat capacity and enthalpy increment of the C15-Fe2Zr phase from 310K to 890K was modelled employing Quasi-harmonic Debye Grüneisen theoretical modelling by identifying the vibrational, electronic, anharmonic and magnetic contributions. Curie temperature(~625K) was determined from the magnetic contribution of the heat capacity.

Synthesis and antifungal efficacy of chitosan nanoparticles against notorious mycotoxigenic phytopathogens

Pathogenic fungi such as Fusarium verticillioides, Alternaria alternata, and Macrophomina phaseolina pose significant threats to agriculture and human health due to their production of carcinogenic mycotoxins. This study explores the antifungal potential of chitosan nanoparticles (ChNPs) against these fungi. ChNPs, synthesized via an ionic gelation method, exhibited a prominent UV-visible absorption peak at 250 nm, confirming successful nanoparticle formation. X-ray diffraction patterns revealed their amorphous structure, while FTIR analysis identified key functional groups, including hydroxyl and amine groups, with an average particle size of 50 nm. Antifungal assays demonstrated that ChNPs inhibited fungal growth in a concentration-dependent manner. Specifically, for F. verticillioides, ChNPs reduced growth by 20-60% at concentrations ranging from 0.03 to 0.15%, achieving complete inhibition at 0.21%. Similarly, A. alternata exhibited a MIC of 0.24%, and M. phaseolina reached a MIC of 0.26% for complete growth suppression. Higher concentrations of ChNPs caused pronounced structural alterations in the fungi, including discoloration, fragmentation, and distortion of hyphae and conidia/sclerotia, which were linked to significant metabolic changes within the fungal cells. This study highlights the effectiveness of ChNPs as robust antifungal agents, demonstrating their ability to disrupt fungal morphology and enzyme activities

Effect of anisotropy field on the resonance frequency and reflection loss shift characteristics of barium hexaferrite ceramics

Abstract For this study, a modified barium hexaferrite based microwave and radar absorbing material was used. Synthesis and characterization of BaFe(12−2x)(MnTi) x O19 (0.1 ≤ x ≤ 1.0) have been prepared by solid state reaction method. The x-ray diffraction patterns reveal that all samples only crystallized into M-type barium hexaferrite after calcination at 1200 °C. Surface morphology images show that the hexagonal flake-like particle is formed at the initial stages of the Mn-Ti substitution level. The magnetic properties measurement reveals that the variation of magnetization values may vary based on preferable site occupation of Mn4+-Ti2+ cations to replace Fe3+ cations. The significant decrease in coercive field (H c) from 3.18 kOe to 0.51 kOe with the increase of Mn-Ti substitution affected the lowering values of anisotropy field (H a ). The maximum reflection loss (RL) positions of BaFe(12−2x)(MnTi) x O19 compositional series are shifted to lower frequency range following the H a trendlines. The maximum RL value equals to 98.42% microwave absorption at 10.5 GHz has been obtained in x = 1.0 (BaFe10Mn0.5Ti0.5O19) composition.

Novel Syntheses of Wide-Band Gap Semiconducting CdxZnx−1Co2O4 of Spinel Nanostructure: Characterization and Optical Properties

AbstractCadmium doped zinc cobaltite spinel structure in the form of CdxZnx-1Co2O4 (0 ≤ x ≤ 1) are synthesized by sol-gel method. The energy dispersive X-ray spectra confirm the synthesis of pure ZnCo2O4 and Cd doped samples nanoparticles. Scanning and transmission electron microscopes images of Cd ZnCo2O4 samples show the cubic crystal structure of the nanoparticles. A good crystallinity of the ZnCo2O4 and its dopants samples are indicated by the sharpness and strong peaks of X-ray diffraction patterns. The particle size is independent of the ratio of incorporated Cd into the ZnCo2O4 matrix. The FT-IR transmission spectrum of each Cdx Zn1-xCo2O4 complex shows two strong vibration peaks that are ascribed to the spinel structure’s octahedral and tetrahedral. The absorption spectra reveal three distinct absorption characteristics for Cdx Znx-1Co2O4 peaking at 268, 532 and 778 nm due to the photoexcitation of electrons from O 2p to Co 3d transitions and d-d transition of Co 3d. N2 adsorption–desorption isotherms for Cdx Znx-1Co2O4 indicate are carried out.

Comparison of ZnO Nanoparticles Prepared by Spray Pyrolysis and Consecutive Method for UV-Driven Photocatalytic Degradation of Methylene Blue

ZnO is a semiconductor material that is widely used for many applications in industries such as solar cells, dye-sensitized solar cells, food packaging, photocatalytic, anti-microbial, light-emitting diode devices, and gas sensors. In this study, ZnO nanoparticles (NPs) have been successfully synthesized using two methods, namely spray pyrolysis and a consecutive method. The consecutive method is a combination of sol-gel and spray drying methods. The objective of this study is to investigate the photocatalytic performance of ZnO fabricated using those methods. Both methods used the same precursor, zinc acetate dehydrate as a source of zinc, but with different solvents and additives. Based on the X-ray diffraction pattern, the ZnO NPs synthesized using spray pyrolysis and a consecutive method exhibited similar polycrystalline hexagonal wurtzite structures. The large crystal sizes of ZnO NPs were obtained using a consecutive method, sol-gel followed by spray drying, in comparison with those from the ZnO spray pyrolysis. In contrast, the particle size of ZnO prepared by the consecutive method was in a smaller range. The SEM analysis implied that the ZnO structures had surface defects. In the UV-driven photocatalytic degradation of methylene blue, ZnO produced by the consecutive method exhibited slightly higher degradation performance than ZnO spray pyrolysis. This performance was attributed to the larger crystal size of ZnO NPs, which provided a longer carrier movement at semiconductor surfaces and reduced electron-hole recombination. Additionally, ZnO NPs produced using the consecutive method underwent agglomeration that leads to a smaller contact surface with methylene blue, obstructing the degradation process.

Effect of Annealing Temperature on the Structural Properties and Performance of ZnO/SnO<sub>2</sub> Nanostructure of AZO-Based Humidity Sensor

Advanced research in metal oxide-based nanotechnology has led to its broad applications, which include humidity sensors as well as electronic devices. Meanwhile, zinc oxide (ZnO)/tin oxide (SnO2) composite nanostructure has established a presence in many electronic devices, and their performance can be further enhanced by electrospraying at high annealing temperatures. This paper explores how annealing temperature influences the structural properties and performance of ZnO/SnO2 nanostructures in AZO-based humidity sensors. The ZnO/SnO2 nanostructures were fabricated on AZO glass utilising electrospraying and then subjected to annealing at various temperatures: 100°C, 200°C, 300°C, 400°C as well as 500°C. The structural characteristics of the synthesized films were analysed utilising Field-Emission Scanning Electron Microscopy (FESEM) as well as X-ray Diffraction (XRD). Additionally, the humidity sensing performance of the films was evaluated based on their response time, sensitivity as well as recovery time. Following the results, a higher annealing temperature resulted in smaller crystallites and smaller diameters within the 71.6–91.9 nm range. Besides, the XRD patterns demonstrate a shift in the (002) peaks towards a higher angle value with incremental annealing temperature. In terms of the humidity sensing performance, the sensitivity level increased with increasing annealing temperature, while the recovery period and response time were reduced. In summary, the annealing temperature significantly influenced the performance of the ZnO/SnO2 composite nanostructures, which recorded the best sensitivity of 173.10, 234 seconds response time, and 80 seconds recovery time after annealing at 500°C.

Combining graph deep learning and London dispersion interatomic potentials: A case study on pnictogen chalcohalides.

Machine-learning interatomic potential models based on graph neural network architectures have the potential to make atomistic materials modeling widely accessible due to their computational efficiency, scalability, and broad applicability. The training datasets for many such models are derived from density-functional theory calculations, typically using a semilocal exchange-correlation functional. As a result, long-range interactions such as London dispersion are often missing in these models. We investigate whether this missing component can be addressed by combining a graph deep learning potential with semiempirical dispersion models. We assess this combination by deriving the equations of state for layered pnictogen chalcohalides BiTeBr and BiTeI and performing crystal structure optimizations for a broader set of V-VI-VII compounds with various stoichiometries, many of which possess van der Waals gaps. We characterize the optimized crystal structures by calculating their x-ray diffraction patterns and radial distribution function histograms, which are also used to compute Earth mover's distances to quantify the dissimilarity between the optimized and corresponding experimental structures. We find that dispersion-corrected graph deep learning potentials generally (though not universally) provide a more realistic description of these compounds due to the inclusion of van der Waals attractions. In particular, their use results in systematic improvements in predicting not only the van der Waals gap but also the layer thickness in layered V-VI-VII compounds. Our results demonstrate that the combined potentials studied here, derived from a straightforward approach that neither requires fine-tuning the training nor refitting the potential parameters, can significantly improve the description of layered polar crystals.

Synergistic Integration of α-Ag2WO4 into PLA/PBAT for the Development of Electrospun Membranes: Advancing Structural Integrity and Antimicrobial Efficacy.

The rising resistance of various pathogens and the demand for materials that prevent infections drive the need to develop broad-spectrum antimicrobial membranes capable of combating a range of microorganisms, thereby enhancing safety in biomedical and industrial applications. Herein, we introduce a simple and efficient technique to engineer membranes composed of polylactic acid (PLA) and polybutylene adipate terephthalate (PBAT) biopolymers and α-Ag2WO4 particles using an electrospinning technique. The corresponding structural, thermal, mechanical, and antimicrobial properties were characterized. X-ray diffraction (XRD) patterns confirmed the integration of crystalline α-Ag2WO4 within the polymer matrix. Scanning electron microscopy (SEM) and Raman confocal microscopy revealed uniformly dispersed α-Ag2WO4 particles in the electrospun fibers, influencing their diameter and surface roughness. Thermal analysis indicated adjustments in the thermal stability and crystallinity of the composites with an increasing α-Ag2WO4 content. Dynamic mechanical analysis (DMA) highlighted variations in storage modulus and glass transition temperatures due to interactions between α-Ag2WO4 and polymer chains, with tensile tests showing an increase in elastic modulus and ultimate tensile strength as the α-Ag2WO4 content increased. Antimicrobial assessments revealed that PLA/PBAT membranes with α-Ag2WO4 showed pronounced antibacterial activity, forming inhibition halos across all samples against Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, and Mycobacterium smegmatis (a surrogate for Mycobacterium tuberculosis). These membranes also exhibited potent antiviral activity against bacteriophage phi 6, a surrogate for SARS-CoV-2, suggesting potential applications in combating infections caused by enveloped viruses. The antimicrobial activities are attributed to the generation of reactive oxygen species (ROS) and the controlled release of Ag+ ions. This work underscores the multifaceted capabilities of α-Ag2WO4-enhanced PLA/PBAT membranes in combating bacterial and viral growth, where both durability and microbial resistance are critical. Taken together, our findings provide a solution for obtaining advanced materials to be applied in a wide range of industrial applications, such as filtration systems, food preservation, antimicrobial coatings, protective textiles, and cleaning products.

Structural, magnetic and dielectric properties in double perovskite La2-xScxCoMnO6 (x = 0.0, 0.1, and 0.2)

The effect of Sc doping on structural, magnetic, and dielectric properties of double perovskite La2CoMnO6 synthesized by solid-state method was investigated. Crystal structure of La2-xScxCoMnO6 (x = 0.0, 0.1, and 0.2) compounds confirmed through X-ray diffraction patterns (XRD). Rietveld refinement of the XRD revealed the monoclinic phase with P21/n space group and the structural properties such as lattice parameter, bond lengths, and bond angles were obtained. Field emission scanning electron microscopy images revealed a uniform grain distribution, and the grain size was increased with increasing Sc content. The elemental mapping confirms the stoichiometry of the compounds. The room temperature Raman spectra confirm the monoclinic crystal structure and reveal two broad peaks viz., Ag, and Bg which were attributed to specific vibrational modes within the (Co/Mn)O6 octahedra. Magnetic measurements show that Curie temperature (Tc1) decreases with Sc substitution of 206 K for x = 0.0–193 for x = 0.2 due to the Co2+-Mn4+ FM coupling and it follows Curie–Weiss law in the paramagnetic region. Impedance spectroscopy studies show that the conductivity in these materials is predominantly due to the intrinsic bulk grains.

Investigating antibacterial activity of biosynthesized silver oxide nanoparticles using Phragmanthera Macrosolen L. leaf extract

The crude leaf extract of Phragmanthera macrosolen L. has been utilized for the first time as an effective reducing, capping and stabilizing agent to synthesize silver oxide nanoparticles (Ag2O NPs) through a green approach. The prepared Ag2O NPs were analyzed by scanning electron-microscopy (SEM), High Resolution Transmission electron microscope (HR-TEM), X-ray diffractions (XRD), Fourier transforms infrared (FTIR) spectroscopy, energy dispersive spectroscopy (EDS), and Ultra-violet visible spectrometry (UV-Vis). The biosynthesized Ag2O NPs applied on gram-positive (S. aureus) and gram-negative (E. coli) bacterial types. FTIR spectral peaks indicate that the phytochemicals in the extract are responsible for the formation of Ag2O nanoparticles. The XRD result shown, poly-crystalline nanoparticles and the average crystalline size calculated was 45.8 nm. UV-Vis analysis shows absorbance existed at 590.5 nm, and the energy band gap calculated through the Tauc relation was 2.1 eV. The SEM images gave a globular and some rod like morphology with diameter of particle obtained between 20.11 and 46.50 nm with some hollow cubic microstructure of Ag2O NPs which makes it suitable for antimicrobial application. The EDS confirms the elemental composition and existence of Ag and O2. The HR-TEM images, specific area electron diffraction (SAED), and XRD patterns confirmed the morphology of Ag2O NPs mean 45.84 nm and polycrystalline nature of the nanoparticles. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were 15 and 30 µl respectively for the samples tested. In this study, it was observed that Ag2O NPs highly sensitive to E. coli than s. aureus. The present study revealed that the possible use of green synthesized Ag2O NPs as potential antibacterial agent.

Synthesis and Characterization of Cu-Co Substituted Strontium Hexaferrite for Magnetic Applications

In this study, the structural and magnetic characterizations of a series of SrCoxCuxFe12-2xO19; 0.0 ≤ x ≤ 0.5 samples, which were produced by the conventional ceramic method, were carried out. The structure was examined by X-ray diffraction (XRD) technique and optical microscopy. A vibrating sample magnetometer (VSM) was used to characterize the ferrimagnetic properties. XRD patterns confirmed the presence of a single phase as Sr-hexaferrite while there were not any peaks of unreacted Fe2O3 phase. The densities varied between 92 – 98 %. XRD patterns of the Sr-hexaferrite samples were slightly modified because of the co-substitution of Cu-Co; however, the magnetic properties changed remarkably. The sample with Cu-Co of x = 0.1 content had the highest saturation magnetization (33.52 emu/g), remanence (19.74 emu/g), and coercivity (4.3 kOe). The synthesized magnetic samples were found to be suitable for the development of attractive ferrimagnetic properties for the current ferrite magnets.

NaW2S4 and RbxWS2: Alternative Sources for 2M-WS2 and 1T'-WS2 Monolayers.

With the recent strive to develop novel quantum materials, including two-dimensional nanosheets, alkali-layered intercalated materials have found a new purpose as starting materials for such compounds. Enriching the library of alkali materials, we present a solid-state synthesis for preparing NaW2S4 (P1̅, No. 2) and RbxWS2 (C2/m, No. 12). Solving their crystal structure from their powder X-ray diffraction patterns, we show that both materials are layered, the former being a slightly distorted version of the latter. We compare the two structures and find that the main difference is the interlayer spacing in the a-direction. We further show that, like their cousin, KxWS2, both compounds can be deintercalated with dilute acid to form superconducting 2M-WS2, with structural and property characterization showing similar behavior, regardless of the starting material. Lastly, we find that both materials can be exfoliated in the same manner as KxWS2 to form superconducting 1T'-WS2 monolayers. We describe an easy one-step method for preparing two new layered materials and, thus, provide more opportunities to access valuable superconducting materials.

∼2 μm broadband luminescence in Tm3+/Ho3+/Er3+-doped tellurite glass

Improving the broadband luminescent properties in ∼2 μm band has always been a serious challenge. This paper proposed a Tm3+, Ho3+ and Er3+ doped combination in tellurite glass, which was synthesized through melt-quenching and characterized by a series of physical and spectral tests. Firstly, tellurite glass of Tm3+–Ho3+ co-doping produced a ∼2 μm broadband luminescence ranging from 1570 to 2200 nm with FWHM (full width at half maximum) of 379 nm under 808 nm pumping. This broadband luminescence originated from 3F4 to 3H6 level transition of Tm3+ and 5I7 to 5I8 level transition of Ho3+. Furthermore, after adding an appropriate amount of Er3+, the luminescent intensity was improved by 116 %, mainly attributed to the direct or indirect energy transfers from Er3+ to Tm3+ and Ho3+ ions. Calculations of Judd-Ofelt spectroscopic parameters and gain cross-sections supported the results obtained from Tm3+/Ho3+/Er3+ doped tellurite glass in ∼2 μm band. In addition, DSC (differential scanning calorimetry) curves exhibited excellent thermal stability, XRD (X-ray diffraction) patterns and Raman spectra disclosed the non-crystalline and network structural units of the synthesized tellurite glasses. The findings in this work demonstrate that tellurite glass with Tm3+, Ho3+ and Er3+ combination is an efficient strategy which can be applied in ∼2 μm band ultra-short pulse lasers and broadband amplifiers.

Study of Pure and Mixed-Phase TiO2 Nanomaterials Synthesized via a Modified Solvothermal Method and Their Optical Properties

The modified-solvothermal method has been used to synthesize pure anatase and anatase-rutile mixed-phase TiO2 nanomaterials using titanium isopropoxide, sodium hydroxide, and triethylamine as primary sources with different calcination temperatures (500 °C and 700 °C). The effect of the precipitating agent, capping agent, and calcination temperatures on the properties, such as structural, morphological, and optical of the resultant nanomaterials has been investigated through several techniques including X-ray diffraction (XRD), Raman spectroscopy, Transmission electron microscopy (TEM), UV–Vis absorption spectroscopy, Scanning electron microscopy (SEM), selected area electron diffraction (SAED), and high-resolution transmission electron microscopy (HRTEM). XRD and Raman spectra confirmed the pure anatase and anatase-rutile mixed structures of the prepared nanomaterials at 500 °C and 700 °C. Furthermore, the Raman active modes confirmed the formation of TiO2. It is noticed that the crystallite size of the nanomaterials increased with increasing calcination temperature of the XRD pattern. The morphologies of the prepared samples were displayed using SEM and TEM micrographs, which are almost the same in shape (cubic and cubic rod mixed). The particle size increased with an increase in calcination temperature and was found to be between 10 and 20 nm, which is similar to the crystallite size. The lattice fringes (d) from HRTEM images are assigned to the XRD plane (101) and (110) plane of anatase and anatase-rutile TiO2, respectively. The SAED exhibited well crystalline nature and confirmed the polycrystalline nature of the prepared nanomaterials by the bright points and the ring patterns. The optical band gap decreased with an increase in temperature and the optical properties are affected by calcination temperature and triethylamine.

Comprehensive approach on La1-xPbxMnO3 (0.2 ≤ x ≤ 0.5) perovskites synthesized by solid state reaction technique

We have synthesized Pb concentrated La manganites La1-xPbxMnO3 (0.2 ≤ x ≤ 0.5) using solid state reaction route to investigate several physical properties such as structural, thermal, magnetic, electronic and elastic properties via both the experimental characterizations and the first principles calculations under the framework of density functional theory (DFT). The structures of the studied perovskites are examined by X-ray diffraction (XRD) pattern and also compared with the crystallographic data obtained by computations. The crystallization and formation of the studied phase of manganites are confirmed by analyzing the thermogravimetric (TG) curve. The temperature dependence of magnetization of all the samples exhibits a ferromagnetic metal phase with the Curie temperatures TC ranging from 334 to 338 K. Although a metal-semiconductor transition is expected at around TC for the measurement of electrical resistivity with temperature but we observe semiconducting behavior because of the resistivity data started from room temperature. The calculated energy dispersion of all the manganites shows metallic conduction in conformity with the available experimental results. All the studied perovskites under investigation possess mechanical stability, malleability as well as anisotropy. The calculated Debye temperatures of all the Pb-doped La manganites show excellent correspondence with the other thermophysical parameters like melting point, phonon thermal conductivity and hardness as well.

Variations in the optical and thermoelectric behavior of ZnCo2O4 nanostructures as a function of synthesis temperature

Zinc cobalt oxide nanostructures were synthesized by electrochemical deposition of zinccobalt alloy at various bath temperatures (15, 30, 45 and 60 ˚C) and its hydrothermal oxidation at 100 ˚C. X-ray diffraction pattern and Raman spectroscopy data reveals the formation of spinal structure of ZnCo2O4. Photoluminescence spectra of the samples exhibit broad peaks with a red shift in the emission energy. Diffused reflectance spectroscopy measured the band gap of the synthesized materials; band gap is 3.06, 3.03, 3.02 and 2.99 eV, for samples electrodeposited at 15, 30, 45 and 60 ˚C, respectively. Optical conductivity of synthesized materials decreases with increasing deposition layers while reflectance shows opposite trend. Thermoelectric set up measures the change in potential difference through synthesized materials when different temperatures are applied and an increment in potential were observed. Seebeck co-efficient and power factor are also studied as function of bath temperature.