Williamson-Hall Plot Research Articles

Correction to: One-step hydrothermal synthesis of Sb2WO6 nanoparticle towards excellent LED light driven photocatalytic dye degradation

Pristine Antimony tungstate nanoparticles prepared via a simple hydrothermal process showcase interesting photocatalytic efficiency, degrading Methylene Blue (MB) completely in 180 min under visible light. In this study, the impact on crystalline quality and related optical properties as well as photocatalytic efficiency of antimony tungstate due to temperature variation during hydrothermal synthesis are explored. While X-ray diffraction (XRD) shows the polycrystalline nature of all synthesized samples, however a systematic increase in crystallite size is revealed by analysing the XRD peak broadening. XRD spectra are further examined by Rietveld analysis showing a change in unit cell volume. Additionally, the overall changes in the corresponding grain size and micro-strain developed in the crystals are determined using the Williamson-Hall plot. Moreover, significant variations in few Raman modes are observed with increasing synthesis temperature. A notable modification in the optical band gap as determined from the absorbance of the UV-Vis spectra is perceived with the change in synthesis temperature within the range of ~2.38-2.57 eV. Further, the photoluminescence measurement indicates that the synthesized antimony tungstate is weak luminescent material with a band-to-band emission at ~468 nm. Finally, photocatalytic efficiencies of the samples are ascertained to change with the synthesis parameter, estimated by decomposing methylene blue (MB), highest degradation rate constant (k) value is observed as 0.015 min -1 for the sample prepared at 180 o C. While the sample with the highest efficiency is also applied for degrading the Rhodamine B (RhB) and Potassium Dichromate (K 2 Cr 2 O 7 ) under visible light irradiation.

In vivo toxicity and antibacterial assessment of Bi2Se3/GO/PVA nanocomposite synthesized via hydrothermal route

Theranostic nanoparticles which incorporate therapeutic and diagnostic properties in a single dose have the potential to advance personalized therapy in biomedical area. In this research work, a nanotheranostic agent i.e., nanocomposites of Bismuth Selenide (Bi2Se3) and Graphene Oxide (GO) in the presence of poly (vinyl) alcohol (PVA) has been fabricated via hydrothermal route. The XRD pattern confirmed the formation of Bi2Se3/GO/PVA nanocomposites showing rhombohedral structure. The crystallite size and lattice strain were calculated by Scherrer formula, Williamson-Hall and Scherrer plot methods. Average crystallite size measured by these methods was 13.06 nm, 12.6 nm and 12.76 nm. UV–Vis spectroscopy was used to study the optical properties such as absorption regions and band gap of the prepared nanocomposites. FTIR and EDAX analysis also confirmed the successful fabrication of Bi2Se3/GO/PVA nanocomposites. SEM revealed sheet-like morphology of prepared nanocomposites. The antibacterial activity of the nanocomposites was studied against two gram-negative bacteria ‘Escherichia coli’ and ‘Pseudomonas’ at 15 μg/ml and 25 μg/ml concentrations by disk diffusion technique. The zone of inhibitions against E. coli at 15 μg/ml and 25 μg/ml were 13 mm and 17 mm while against Pseudomonas were 15 mm and 18 mm. Also, the in vivo toxicity of the prepared Bi2Se3/GO/PVA nanocomposites was investigated on Swiss Albino mice with a high dose of 20 mg/kg at a time period of 2, 7, 14 and 30 days by analyzing hematological, biochemistry and pathological tests. No severe damage was observed in mice during whole treatment time which ensures that the synthesized nanocomposites were non-toxic. Moreover, p-value was calculated which shows that our nanoparticles are safe and that the manufactured nanoparticles have no significant effect on mice. This research work shows that Bi2Se3/GO/PVA nanocomposites are biocompatible and can be further studied for different biomedical applications like CT imaging, Photoacoustic imaging as well as Photothermal therapy.

Photocatalytic performance of KCoPO4 for the methyl violet oxidation

KCoPO4 was elaborated by hydrothermal route at 453 K and the photocatalytic properties were reported for the first time. The compound crystallizes in a hexagonal symmetry with the lattice constants: a = 18.206 (0) Å and c = 8.513 (5) Å. The average crystallite size determined from the Williamson Hall plot (21 nm) is half of that obtained from the XRD peak broadening (40 nm) and is characteristic of a nanomorphology. The diffuse reflectance gives an optical transition at 1.82 eV, directly permitted due to the degeneracy lifting of Co2+: 3d7 in tetrahedral site. The SEM image displayed a hexagonal section of regular grains where the elements of the sample are given by the EDX analysis. The phosphate is stable at neutral pH and is successfully tested for the oxidation of methyl violet (MV). The flat band potential 0.62 VSCE was determined from the capacitance-potential graph in Na2SO4 medium. The valence band deriving from O2–: 2p character (2.24VSCE / 6.99 eV) has a strong oxidizing ability to mineralize the dye by OH radical. More interesting, we optimized the experimental conditions like the catalyst dose, pH and radiation sources. The best result with a degradation of 97 % was reached for a solid / liquid ratio (2:1) while 94 % is obtained for pH 10. Under solar irradiation (23 mW/ cm2), a total MV photodegradation is observed within 2.5 h. The as-prepared material shows relatively a good stability and reusability after three consecutive tests.

One-step hydrothermal synthesis of Sb2WO6 nanoparticle towards excellent LED light driven photocatalytic dye degradation

Pristine Antimony tungstate nanoparticles prepared via a simple hydrothermal process showcase interesting photocatalytic efficiency, degrading Methylene Blue (MB) completely in 180 min under visible light. In this study, the impact on crystalline quality and related optical properties as well as photocatalytic efficiency of antimony tungstate due to temperature variation during hydrothermal synthesis are explored. While X-ray diffraction (XRD) shows the polycrystalline nature of all synthesized samples; however, a systematic increase in crystallite size is revealed by analysing the XRD peak broadening. XRD spectra are further examined by Rietveld analysis showing a change in unit cell volume. Additionally, the overall changes in the corresponding grain size and micro-strain developed in the crystals are determined using the Williamson-Hall plot. Moreover, significant variations in few Raman modes are observed with increasing synthesis temperature. A notable modification in the optical band gap as determined from the absorbance of the UV–Vis spectra is perceived with the change in synthesis temperature within the range of ~ 2.38–2.57 eV. Further, the photoluminescence measurement indicates that the synthesized antimony tungstate is weak luminescent material with a band-to-band emission at ~ 468 nm. Finally, photocatalytic efficiencies of the samples are ascertained to change with the synthesis parameter, estimated by decomposing methylene blue (MB), highest degradation rate constant (k) value is observed as 0.015 min−1 for the sample prepared at 180 °C. While the sample with the highest efficiency is also applied for degrading the Rhodamine B (RhB) and Potassium Dichromate (K2Cr2O7) under visible light irradiation.

Polypyrrole-bismuth selenide (PPY-Bi2Se3) composite-thermoelectric characterization and effect of nickel doping

Conducting polymer based thermoelectric composites have received an increasing attention due to their inexpensive process, low thermal conductivity, durability and flexibility in last few years. Compositing polymer with chalcogenides imparts enhancement of properties by suitable choice of dopant. The performance of Polypyrrole-bismuth selenide (PPYBS) and polypyrrole-nickel doped bismuth selenide (PPYBSN) composites synthesized solvothermally followed by chemical oxidative in situ polymerization technique for thermoelectric applications are compared. X-ray diffraction (XRD) pattern confirms the uniform growth of polypyrrole (PPY) matrix on Bi2Se3 nanoplates. Williamson-Hall (W-H) plots give crystallite size 26.3 and 22.9 nm for PPYBS and PPYBSN respectively. Comparative results for both the samples are further analysed employing density functional theory (DFT) to explore the underlying electronic structure and charge transfer processes in the nanocomposites which shows that after forming the composites with Bi2Se3 and nickel doped Bi2Se3density of state increases compared to pure PPY and hence conductivity increases from 1250 S/m to 1782 S/m and 2370 S/m respectively. Temperature variations of thermoelectric performance are measured in temperature range 303–373 K. Thermoelectric figure of merit (ZT) are 0.0108 and 0.0149 for PPYBS and PPYBSN respectively at room temperature.

Dry Reforming of Methane on Ni/Nanorod-CeO2 Catalysts Prepared by One-Pot Hydrothermal Synthesis: The Effect of Ni Content on Structure, Activity, and Stability

The nanorod morphology of the CeO2 support has been recognized as more beneficial than other morphologies for catalytic activity in the dry reforming of methane. Ni/nanorod-CeO2 catalysts with different Ni contents were prepared by one-pot hydrothermal synthesis. Samples were characterized by X-ray diffraction (XRD), H2-temperature-programmed reduction (H2-TPR), H2-temperature-programmed desorption (H2-TPD), field emission scanning electron microscopy/energy dispersive spectroscopy (FE-SEM/EDS), Brunauer–Emmet–Teller (BET) and Barrett–Joyner–Halenda (BHJ) analysis. The effect of Ni content on the size and the intrinsic strain of ceria was analyzed by the Size–Strain plot and Williamson–Hall plot of XRD data. The average Ni particle size and Ni dispersion were determined by H2-TPD. XRD and H2-TPR analysis revealed a strong Ni–support interaction that limited nickel sintering. The activity for the dry reforming of methane was tested with the stoichiometric mixture CO2:CH4:N2:He = 20:20:20:140, gas hourly space velocity (GHSV) = 300 L g−1 h−1, and temperatures in the range of 545–800 °C. The turnover frequency (TOF) value increased linearly with the average Ni particle size in the range of 5.5–33 nm, suggesting the structure sensitivity of the reaction. Samples with Ni loading of 4–12 wt.% showed high H2/CO selectivity and stability over time on stream, whereas the sample with a Ni loading of 2 wt.% was less selective and underwent rapid deactivation. Only a small amount of nanotubular carbon was observed by FE-SEM after the time-on-stream experiment. Deactivation of the low-Ni-content sample is ascribed to the easier oxidation of the small Ni particles.

Effect of Li+, Mg2+, and Al3+ Substitution on the Performance of Nickel Ferrite-Based Hydroelectric Cells

Defect engineering in nickel ferrite has been performed to enhance the power output of the hydroelectric cell (HEC). Oxygen vacancies can be tuned in the ferrite using different valence element substitutions to enhance water dissociation by hydroelectric cells. In this work, Li+, Mg2+, and Al3+ substituted at the nickel site in nickel ferrite (NiFe2O4) are synthesized and studied for hydroelectric cell devices. Introducing these Li+, Mg2+, and Al3+ substituents (of a different atomic radius and valence charge state) in nickel ferrite leads to the generation of oxygen vacancy differently, which is discussed thoroughly in this work. In comparison to Mg and Al, lithium substitution lowers the overall cationic charge in nickel ferrite, leading to formation of a high number of oxygen vacancies for overall ionic charge compensation. Lithium-substituted nickel ferrite (NLFO) has a high number of defects (oxygen vacancies, etc.) compared to Mg-substituted (NMFO) and Al-substituted (NAFO) nickel ferrite, confirmed by X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL) spectroscopy. The highest peak area of oxygen vacancies in the O 1s core-level spectra has been obtained for the case of NLFO among NLFO, NMFO, and NAFO. These vacancy sites provide a large number of adsorption sites for water molecule adsorption and dissociation. A high lattice strain (9.83 × 10–4) is induced in NLFO calculated by the Williamson–Hall plot. The porous nature of all samples has been confirmed from FESEM and BET analysis. The charge transfer processes in dry and wet HECs have been analyzed by fitting an equivalent RC circuit in the Nyquist spectra. The lithium-substituted nickel ferrite HEC with rich oxygen vacancies generates a high short-circuit current of ∼58.7 mA, which is ∼2 times higher than that of NMFO HEC and ∼3 times higher than that of NAFO HEC.

Phase recognition, structural measurements and photoluminescence studies of reddish-orange-emissive YAlO3:Sm3+ perovskite nanophosphors for NUV energized WLEDs

Orthoaluminate perovskite-type YAlO3:xSm3+ (x = 0.01 to 0.04 mol) nanocrystalline materials were synthesized successfully through solution combustion (SC) synthetic method. The prepared nanomaterials were characterised by means of X-ray diffraction (XRD) assisted Rietveld refinement, energy dispersive X-ray (EDX) spectroscopy, fourier-transform infrared (FTIR) spectroscopy and photoluminescence (PL) studies along with photometric parameters. The XRD pattern displayed that the diffraction lines were very well matched with JCPDS # 38-0222 and confirmed the phase purity of phosphors. Rietveld refinement of representative Y0.96AlO3:0.04Sm3+ phosphor showed that the prepared materials were crystallized into orthorhombic crystal system having space group pbnm (62), crystallographic constrains α = β = γ = 90o, formula units (Z) = 4 and refinement parameters Rp = 5.65%, Rwp = 7.44 and χ2 = 3.25 %. FTIR spectra indicated the presence of characteristics vibrations of functional groups in phosphors. Transmission electron microscopy (TEM) studies represents the presence of irregularly sized particles with spherical morphology. Crystallite size of the doped phosphors was estimated by Scherrer's formula followed by Williamson-Hall (W-H) plot. The strongest emission accredited to 4G5/2 →6H7/2 transition was found to be at 604 nm, which accountable for their reddish-orange emission. The strongest excitation line was observed at 405 nm corresponding to 6H5/2→6P3/2 intraconfigurational f-f transition which quantified that the phosphor could be proficiently applied in NUV (near visible ultraviolet) energized LED applications.

Exploration of spectroscopic, surface morphological, structural, electrical, optical and mechanical properties of biocompatible PVA-GO PNCs

The studies carried out in this paper are directed towards preparation of nanocomposite films of PVA (polyvinyl alcohol)-GO (graphene oxide) with variable wt% of GO by simple solution mixing technique and exploration of spectroscopic, surface morphological, structural, optical, electrical, and mechanical properties. In this article, the detailed molecular structure of PVA-GO polymer nanocomposites (PNCs) was optimized by using the Gaussian code (B.01 version). Experimentally, the structural information was gathered by using the X-ray diffractometer and determined the crystalline size (varying from 12. 82 nm to 24.62 nm for 1–5 wt% of GO in PVA/GO PNCs) and micro-strain (varying between 7.21 × 10−3 and 42.12 × 10−3) produced in the samples through Williamson-hall plot. The existence of the functional groups with their role in the nanocomposites was also examined with the help of FTIR technique. In order to identify the Raman bands (availability of D and G bands at ~1340 and 1595 cm−1, respectively, while the 2D band at ~2910 cm−1) and corresponding structural changes were studied by Raman spectrometer (with the usage of 532 nm laser). The study of surface morphology was performed by utilizing the AFM and FESEM (with EDAX) techniques and effect of GO on the surface roughness of the nanocomposite film was studied. The r.m.s. roughness of the films were set up to be 90.375 nm, 96.449 nm, 98.120 nm, 99.006 nm and 99.891 nm for GO of 1–5 wt%, respectively. The optical properties were determined using UV–Vis-NIR spectrophotometer and tuning of optical bandgap (varied from 3.56 eV to 2.45 eV with 1–4 GO wt%) was investigated. The resulting variation due to GO concentration was also confirmed with structural information. The electrical characteristics (capacitance, dissipation factor and electrical conductivity) were also investigated. The DMA analysis of the nanocomposites was performed to measure the mechanical property (Young's Modulus varying from 2 GPa to 16 GPa for 1–5 GO wt%) and found that the nanofillers (GO) plays an important role to enhance the various abovementioned properties.

MnO2-SnO2 Based Liquefied Petroleum Gas Sensing Device for Lowest Explosion Limit Gas Concentration

In this work, MnO2-SnO2 nanocomposite based below lower exposure limit (0.5–2.0 vol%) sensing device for liquefied petroleum gas (LPG) is reported. The synthesized material is highly crystalline with an average crystallite size of 16.786 nm, confirmed by the X-ray diffraction pattern. Williamson-Hall plot shows that the induced strain of 2.627 × 10−4, present in the nanocomposite, lies between the induced strains of both of its constituents. The XRD pattern of nanocomposite contains the cubic phase of MnO2 and the tetragonal phase of SnO2. Tauc plot shows the optical energy band gap of MnO2, SnO2, and MnO2-SnO2 of 3.407 eV, 3.037 eV, and 3.202 eV respectively. The surface morphological investigation shows the brush-like structure which enhances sensor performance by providing activation sites. The energy dispersive X-ray (EDS) spectrum found that materials are highly pure because other peaks are not observed. The functional group analysis by using FTIR found to be Sn–O and Mn–O both vibration bands existed. The highest sensor response was found to be 2.42 for 2.0 vol% whereas for a lower concentration of 0.5 vol% the sensor response was observed to be 1.44. The fast response and recovery of this sensing device were found to17.30 and 23.25 s respectively for 0.5 vol% of LPG.

Structure refinement, microstrains and crystallite sizes of Mg-Ni-phyllosilicate nanoscroll powders

The morphology and structure of (Ni x Mg1−x )3Si2O5(OH)4 synthetic phyllosilicate nanoscrolls have been studied by means of electron microscopy and X-ray powder diffraction. Scrolling of phyllosilicate layers originates from size differences between octahedral and tetrahedral sheets. This strain-energy-driven process raises a number of questions, including the preferred direction of scrolling (along the a or b axis) and the presence of residual microstrain. In order to clarify these points, the structure of (Ni x Mg1−x )3Si2O5(OH)4 phyllosilicates (x = 0, 0.33, 0.5, 0.67, 1) was first described by a monoclinic Cc (9) unit cell, whose parameters decrease with increasing Ni concentration. The Williamson–Hall plots constructed for x = 0 and 0.67 reveal the absence of microstrain, which suggests that scrolling is an effective means of stress relaxation. The sizes of the crystallites were determined by using Rietveld refinement with predefined needle-like models and fundamental parameter fitting with crystallites of arbitrary form. Both approaches show qualitative and quantitative correlation, in terms of aspect ratio, with electron microscopy data. At the same time, the phyllosilicates studied do not demonstrate one preferred direction of scrolling: instead, there might be a mixture of chirality vectors codirected with the a or b axis, with the proportion altering with Ni concentration.

The modified Williamson-Hall plot and dislocation density evaluation from diffraction peaks

Diffraction peak profiles were calculated numerically for dislocation ensembles with different spatial arrangements and correlations between the Burgers vector signs. The latter property determines the stored elastic energy in the crystal and the width of the diffraction peaks. It is shown that within the approximation of the asymptotic line-profile theory the relationship between peak breadth and the magnitude of the diffraction vector in the modified Williamson-Hall (mWH) plot is linear. The slope of the line is proportional to the arrangement parameter M0.3 and to the square root of the dislocation density. The only rigorous way for determining M is the asymptotic Fourier method. Therefore, the evaluation of the dislocation density from the mWH-plot alone is impossible and should be avoided. The mWH plot however, is very useful in practice. Its linearity indicates a consistent asymptotic line-profile analysis.

HIGHLY LUMINESCENT CU DOPED SNO2 NANOCOMPOSITES AND THEIR PHOTOCATALYTIC APPLICATION AS EXCELLENT METHYLENE DYE REMOVAL

Cu doped SnO2 nanostructures were grown using hydrothermal method. The solution was obtained by dissolving stannous chloride in distilled water (DW) with ammonium as surfactant followed by irradiation with ultrasonic vibrations. Obtained samples were characterized by structural, morphological and optical studies. All the peaks in the Xray diffractograms are identified and indexed as structure. In pure form of Cu nanoparticles shows crystalline structures and in high concentration of Cu in SnO2 nanoparticles shows the disappearing of peaks occurring as the pH increases. Negative slope of Williamson–Hall plots indicates compressive strain. Particle size of Cu doped SnO2 nanostructures decreases with increasingthe doping concentration. An optical study shows good luminescence in visible region. A strong quantum effect was evident from the far blue shifted optical direct and indirect band gap. 80% of MO dye removed from waste water.

Investigation on Structural Properties of BiFeO3–SmFeO3 Ceramic

This work is mainly focused of Perovskite types of ceramic-composites of BiFeO3–SmFeO3 (BFO-SFO) that have been synthesized using solid-state reaction route. The polycrystalline samples of rare-earth ferrite-modified bismuth ferrite (i.e., (BiFeO3)1-x + (SmFeO3)x with x = 0.0, 0.1, 0.2) were synthesized by a high-temperature solid-state reaction route. The ceramic-composite powders were characterized by powder X-Ray diffraction (PXRD) to confirm the existence of mixed crystallographic phases. The induced strain upon loading SmFeO3 (SFO) in BiFeO3 (BFO) matrix has been computed with the aid of Williamson-Hall (W-H) plot. Surface morphologies of ceramic-composite powders have been studied using Field Emission Scanning Electron Microscope (FESEM) images. The overall results obtained have been discussed in detail.

Enhanced dielectric and optical performance of (Cu, Ag) co-doped ZnO nanostructures for electronic applications

ABSTRACT Pure and Cu/Ag co-doped ZnO nanoparticles were synthesised by the co-precipitation method. The phase and structural analysis of ZnO nanoparticles were examined by using XRD and Williamson-Hall plots. XRD spectra revealed that prepared samples exhibit hexagonal wurtzite structure of ZnO. The change in lattice parameters, bond length, dislocation density and strain indicates that Cu and Ag were successfully incorporated. UV vis studies indicated the red shift in the absorption band attributed to defects induced after dopant additions. The dielectric measurements showed that the dielectric constant was found to increase and the dielectric loss decreases with increase in dopant percentage. Additions of Cu and Ag in ZnO lattice may lead to supplement grain boundary defects which can increase polarisation. The relatively higher values of ac conductivity were also found due to modulation of charge carrier density after dopant additions which suggest that the diffusion controlled charge carrier hopping mechanism is involved.

Electrospinning and characterization of magnetoelectric NdFeO3–PbZr0.52Ti0.48O3 Core–Shell nanofibers

A core–shell nanofiber with a neodymium orthoferrite (NdFeO3) core and lead zirconium titanate (PbZr0.52Ti0.48O3) shell was prepared in this study using the sol-gel electrospinning method. Structural properties of the nanofiber were analysed using the X-ray diffraction (XRD) method, which revealed that a perovskite structure was formed. The strain was calculated using Williamson-Hall (W–H) plot. Functional groups of the nanofiber were studied using Fourier transform infrared (FTIR) spectroscopy. Morphological studies revealed the core diameter of the nanofiber to be 65 nm and its shell diameter to be 128 nm. The elemental analysis of core-shell nanofiber was made using Energy Dispersive X-ray Spectroscopy (EDS) which proved the formation of NdFeO3 and PbZr0.52Ti0.48O3 composite in the stoichiometric ratio. Topography analysis using atomic force microscopy found the average fibre diameter to be 135 nm. The nanofiber exhibited antiferromagnetic behaviour, with a saturation magnetization of 0.48 emu/g. Dynamic contact electrostatic force microscopy (DC-EFM) studies revealed that the nanofiber showed domain-switching behaviour. The ferroelectric hysteresis plots showed that the nanofiber exhibited a maximum polarization of 5.45 μC/cm2 at 20 kV/cm. Also, its dielectric constant was 268 at 100 Hz. The leakage current study revealed a butterfly-shaped J-E loop, which further proved the ferroelectric behaviour of the nanofiber. The mechanism behind the leakage current was identified to be the Schottky emission. The P-E loops recorded under external magnetic fields of different strengths exhibited variations in the polarization, indicating the presence of cross-coupling between electric and magnetic order parameters. Because of the high dielectric constant displayed by the magnetoelectrically active NdFeO3–PbZr0.52Ti0.48O3 core–shell nanofiber, it can be a promising candidate for a number of applications, such as data storage devices, multimedia devices, spintronics and magnetic field sensors.

Optical and Structural Studies of Tin Disulfide (SnS2) Synthesized by Facile Hydrothermal Method

Transition metal dichalcogenides (TMDCs) have found diverse applications for intrinsic semiconducting and tunable electronic properties mediated via the van der Waals interaction between the adjacent chalcogen planes. Therefore, the large-scale production of TMDCs without compromising the material properties is the major challenge at the present moment. We follow a simple, cost-effective, and environmentally friendly hydrothermal technique for synthesizing tin disulfide (SnS2). The optical properties are investigated using UV-visible, photoluminescence (PL), Raman, and FTIR spectroscopy. The UV-visible absorption spectra of pure SnS2 show a broad absorption peak located at 340 nm, and the corresponding optical band gap energies are estimated to be 2.14 and 4.02 eV, respectively. The PL spectra display a sharp emission peak at 561 nm due to the radiative recombination of bound excitons for the excitation wavelength of 340 nm. FTIR is used to observe the existence of functional groups in the material. The absorption peak observes at 625 cm-1 corresponds to the vibration of the Sn-S bond. From Raman spectra, a sharp peak appears at 314 cm-1, corresponding to the A1g mode of pure SnS2, which occurs due to the out-of-plane stretching vibration of sulfur atoms in the SnS2 material. The XRD is used to identify structural phases. The sharp diffraction peaks at 2Ɵ = 15.17ᴼ and 28.55ᴼ corresponds to (001) and (100) planes, respectively, that suggest the hexagonal phase of pure SnS2. Interplanar spacing is estimated using Bragg’s law, and the value is found to be 5.83 Å. The average crystallite size is estimated to be 28 nm from the Williamson-Hall plot, which is comparable with the crystallite size calculated from Scherrer’s formula.

Influence of dislocation structure on electrical and spectroscopic properties of MoOx/p-CdTe/MoOx heterostructures

The defective structure of p-CdTe:Cl single crystals and MoOx/p-CdTe/MoOx heterostructures were investigated by high-resolution X-wave diffractometry methods. Different models of dislocation systems were used and the dislocation densities were estimated from the Williamson-Hall plot. It is noted that significant deformations of the mismatch in the transition layer negatively affect the current–voltage characteristics of heterostructures.

The role of lanthanum in the structural, magnetic and electronic properties of nanosized mixed manganese ferrites

Manganese ferrite nanoparticles with either Fe3+ or Mn2+ substitution by La3+ (MnFe2O4, La0.125MnFe1.875O4 and La0.125Mn0.875Fe2O4) were obtained by sol–gel method. A single phase corresponding to inverse spinel crystal structure was detected. Lattice parameter increases by incorporating La3+. Microstrain and crystallite size (∼9 nm) were obtained by Williamson-Hall (W-H) plots and field emission scanning electron microscopy (FE-SEM), respectively. Lanthanum ions promote a superparamagnetic behavior at 300 K, while at low temperature ferrites acquire a typical ferromagnetic behavior according to the blocking temperature (TB) detected by zero-field-cooled and field-cooled (ZFC/FC) magnetization measurement. Lanthanum modifies slightly the chemical environment and the cation distribution, promoting the Fe partial reduction and the subsequent Mn oxidation. Experimental results were compared with those obtained by Density Functional Theory (DFT) calculations. The band gap energy (Eg) of MnFe2O4 at 0 K is 1.109 eV (DFT) and no significant change was observed by incorporating lanthanum, while at 300 K (UV–visible diffuse reflectance spectroscopy, UV–vis), Eg is 1.796 eV and increases up to 1.835 and 1.842 eV due to the substitution, by La3+, of Fe3+ and Mn2+, respectively. The role of lanthanum in the Mn-ferrite is the decrease in the magnetic properties by substituting either Fe3+ or Mn2+ due to the electronic transition from the high spin to low spin configuration by the presence of this rare earth element located at the octahedral sites.

Physio-chemical characterizations and antimicrobial properties of nano-sized Mg-Zn ferrite particles for biomedical applications

ABSTRACT The nano-sized magnesium doped zinc ferrite (MgxZn1-xFe2O4 for x = 0.2 and 0.6) has been synthesised for biomedical application through two different routes (sol–gel and hydrothermal). The x-ray diffraction pattern showed the single phase of ferrite. The crystallite sizes and lattice parameters of Mg-Zn ferrite were obtained by three different methods viz. Scherrer formula (X’pert high score), Maud analysis (Rietveld refinement software), and Williamson Hall Plot. The field emission scanning electron microscopy revealed the near-spherical and dumbbell-shaped morphology of Mg-Zn ferrite. The vibrating sample magnetometer showed the increasing magnetic properties on increasing Mg doping. The elemental dispersive spectroscopy analysis revealed the presence of desired elements. The antimicrobial assay against E. coli (gram-negative) and S. aureus (gram-positive) bacteria showed a clear zone of inhibition. The Mg-Zn ferrite showed good magnetic and antimicrobial properties synthesised via the sol–gel route, which can be further used for possible drug delivery applications.