Williamson-Hall Plot Research Articles

Zn-Mg-La nanoferrites for storage and high frequency devices with augmenting the photocatalytic performance

Crossbred photocatalysts with dielectric and magnetic are crucial by its vantage of being convenient in sundry applications. In this paper, lanthanum with large percentages doped zinc magnesium ferrite (Zn0.8Mg0.2LaxFe2-xO4) (ZML) nanoparticles with x ranging from 0.0 to 0.5 prepared via a combustion method. The spinel structure of ZML nanoparticles is asserted with further La3+ substitution. The lattice parameter is found to increase from 8.379 to 8.433 Å with a monotonic shift in diffraction peak (311) toward lower degree angles (2θ = 35.28ο to 34.0°). Williamson-Hall plots established increasing demeanor for crystallite size (28–49 nm) and lattice tensile strain for ZML nanoparticles. FE-SEM depicts spongy or carded wool-like structure with porous nature. EDX spectra revealed the presence of all chemical elements. HRTEM and SAED micrographs confirmed the nanosized polycrystalline nature of samples. The finger print ferrite FTIR absorption bands were obtained. The crystallite size role and magnetocrystalline anisotropy property of La3+ are the substantial reasons for the peculiar demeanor of coercivity. The increasing attitude of dielectric constant as well as conductivity and decreasing one for tangent loss are based on the effective role of porosity and crystallite size of samples. Tauc’s plots introduced direct allowed Eg for ZML nanoparticles with a red shift from (1.92 eV at x = 0.0–1.66 eV at x = 0.5); owing to three factors. The degradation efficiency of RhB over ZML photocatalyst is improved comparing with that of pure RhB reaches (84.43% for x = 0.5 in 270 min). The optimum features of the nanoferrite Zn0.8Mg0.2La0.5Fe1.5O4; high coercivity, dielectric constant, conductivity, photodegradation percentage, besides low loss and energy gap make it advisable for various applications as storage and high frequency devices and photocatalyst for disposing effluents from water.

Synthesis and magnetic interaction on concentrated Fe3O4 nanoparticles obtained by the co-precipitation and hydrothermal chemical methods

In this work, a comparative study of the synthesis and magnetic properties of Fe3O4 nanoparticles obtained by the co-precipitation and hydrothermal methods with the adding of the sucrose as a chelating agent is reported. The analysis of transmission electron microscopy (TEM) show that particles are spherical-like with an average particle size ranging of 3 ≤d≤ 10 nm. Magnetization measurements as a function of an applied magnetic field and temperature are consistent with a superparamagnetic behavior with small TB values. The analysis of the MvsH loops measured at T = 2 K and Zero-Field-Cooled and Field-Cooled (ZFC−FC) curves allows us to estimate the average diameter of Fe3O4 nanoparticles. These results are in good agreement with those obtained through X-ray diffraction (XRD) data (by using Scherrer equation and Williamson-Hall plot) and slightly smaller than those estimated using TEM images. Finally, ZFC−FC data are also used to evaluate the effective anisotropy constants, which are similar to those values found in literature considering the average sizes values estimated by different techniques.

Synthesis, Characterization, Optical and Electrical Properties of Citrate Mediated Terbium Doped ZnO Nanoparticles for Multifunctional Applications

Terbium doped ZnO nanoparticles were synthesized via co-precipitation method using sodium citrate as a capping agent to study optical and electrical properties. The crystalline structure and the unit cell parameters were refined by the Reitveld analysis, infers that the nanomaterials crystallized in hexagonal zincite structure. The calculated grain size using Scherrer’s equation and the Williamson hall plot is found to be similar in values. Ensuing particle gives green emission due to the transitions from the excited 5D4 to the lower 4f energy levels. From the dielectric study, it is confirmed that the synthesized nanocrystal is useful for higher frequency applications.

Comparison of Ag and Zr substitution on the structural and optical behaviour of ZnO nanoparticles

Silver (Ag) and zirconium (Zr) doped ZnO (Ag-doped ZnO and Zr-doped ZnO) nanostructures were prepared utilizing the co-precipitation method, and the physical properties of all prepared samples were characterized utilizing X-ray diffractions, energy dispersive X-ray, and UV-Vis spectroscopy. Ag-doped ZnO and Zr-doped ZnO exhibit the hexagonal wurtzite structure, and the elemental analysis shows that the Ag and Zr concentrations on the samples were 3 atomic percent (at.%). The grain sizes of both samples were examined using Williamson-Hall plots with three different approaches using the uniform deformation model. The band gap energy of the prepared samples investigated using Kubelka-Munk analysis showed a red-shift to a lower energy compared to the band gap of ZnO nanoparticles, and the Zr-doped ZnO shows the lowest band gap energy. The red-shift of the band gap energy from Ag-doped ZnO and Zr-doped ZnO is probably due to the decreased grain size of both samples.

Low temperature synthesis and influence of rare earth Nd3+ substitution on the structural, magnetic behaviour of M-type barium hexa ferrite nanomaterials

The (Nd3+) substituted M-type Barium hexaferrite (BaFe12-x NdxO19) with (Nd3+) concentration (x = 0, 0.25, 0.50, 0.75, 1.00) is prepared using citrate precursor based sol gel process. The X-ray intensity pattern confirms that synthesized nanomaterials were in the pure phase and they possess hexagonal crystal structure having P63/mmc space group. Crystallite size and lattice strain values decreased with increment in concentration of Nd3+ in Barium Hexaferrite lattice. The Williamson-Hall plot is utilized for calculating these structural parameters. The Saturation Magnetization and Anisotropy values are highest for (0.25) mole (Nd3+) in Barium Hexaferrite lattice. All the prepared nanomaterials shows pure phase with good magnetization (43.11 emu/g–56.90 emu/g), retentivity (21.41 emu/g–29.02 emu/g) at room temperature. Curie temperature was found to be shifted to 429 °C from 446 °C with respect to increasing molar concentration of Neodymium.

Synthesized vanadium doped ZnO through the co-precipitation method

In this study, vanadium modified ZnO nanoparticles were synthesized using the co-precipitation method. The amount of vanadium content was varied from 5, 8, and 16 atomic percentages (at.%). The structural properties of the prepared samples were characterized using X-ray diffraction (XRD). The results show that all the prepared samples had a hexagonal wurtzite structure from ZnO nanoparticles. The grain size and lattice strain were calculated using Williamson-Hall plots with a uniform deformation model approach. The elemental analysis characterized using energy dispersive X-ray measurement indicated that the total vanadium concentrations of the samples were about 5, 8, and 16 at.%. In addition, the UV-Vis reflectance analyses show that the reflectance spectra of vanadium doped ZnO decreased in visible light region with increased vanadium content.

New Co-MnO based Nanocrsytallite for photocatalysis studies driven by visible light

ABSTRACT A proficient, eco-friendly, and cost-effective catalyst for remediation of organic contaminants in the environment is a burning issue in recent decades. In the present study, the cobalt doped MnO (Co-MnO) photocatalyst was synthesized via cost-effective and environmentally friendly reverse micelle route. The X-ray diffraction (XRD) results confirmed the synthesis of well-defined cubic-phased MnO and Co-MnO. XRD structural parameters and Williamson-Hall plot of MnO and Co-MnO samples were also explained in detail. Optical band gap analysis revealed an enhanced red-shift of 2.16 eV for Co-MnO photocatalyst as compared to pristine MnO (2.81 eV). The remediation efficiency of pristine MnO and its cobalt doped sample was also was tested using an organic contaminant crystal violet (CV) dye. Excellent synergistic effects of adsorption and photocatalysis at normal conditions, simple degradation mechanism, impressive kinetic investigation, and the low dose utilization proved that the newly synthesized Co-MnO photocatalyst might have commercial applications for environmental applications.

Preparation of NiCrAlY/nano-CeO2 powder with the core-shell structure using high-velocity oxy-fuel spraying process

In this study, NiCrAlY/nano-CeO2 feedstock powders with core-shell structure were prepared via ball-milling process and subsequent direct spraying of the powder into the water using high-velocity oxy-fuel (HVOF) spraying method. X-ray powder diffraction, scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDS), Atomic absorption spectroscopy (AAS) and Ultraviolet–visible spectroscopy (UV–Vis) tests were utilized for characterization of the processed powders. Results indicated that powders with core-shell structure were successfully prepared using this method. In this regard, each core-shelled particle consisted of a relatively homogeneous and uniform nanocomposite layer (shell) including dispersed CeO2 nanoparticles on the surface of NiCrAlY together with ultra-fine grained structure. Furthermore, the absorbance spectra of the core-shelled powder is different from the ball-milled powder due to the homogenizing and stabilizing effect of CeO2 nanoparticles in the shell after direct HVOF spraying. The consequences of the Williamson-Hall plot analysis demonstrated that the core-shelled NiCrAlY/nano-CeO2 powder has smaller crystallite size and also has a considerable lattice strain compared to the conventional NiCrAlY powder owing to the rapid melting and solidification during direct HVOF spraying into the water.

Structural, opto-electronic and photoelectrochemical properties of tin doped hematite nanoparticles for water splitting

For application in photoelectrochemical water splitting, pristine and Sn doped (1%, 3% and 5%) hematite nanoparticles were prepared hydrothermally via a two step heating process. XRD results showed that the products match the rhombohedral crystal system. The peak broadening of hematite nanoparticles due to small crystallite size and strain were analyzed by Scherrer's equation and Williamson Hall plot method respectively. A decrease in crystallite size and an increase in lattice strain is observed with dopant addition. Structural change from nanorods to nanocorals is seen for the Sn doped hematite products. Selected Area Diffraction patterns reveal crystallinity of both the doped and undoped powders. Sn 3d XPS peak analysis reveals that Sn has been doped into the hematite lattice. Linear Sweep Voltammetry and Electrochemical Impedance Spectroscopy analysis confirm that 1% Sn doped hematite has the highest photocurrent density (3 mA/cm2 at 1 V vs. Ag/AgCl) and least charge transfer resistance among the doped products. UV-VIS, Photoluminescence and Mott-Schottky analysis further show that optimum optical and electrical properties are observed for hematite doped with 1% Sn.

Electrochemical, structural, compositional and optical properties of Cuprous Selenide thin films

This work focussed the electrochemical growth, structural, compositional and optical properties of Cuprous Selenide thin films. An electrochemical route has been used to prepare Cuprous Selenide thin films on different non transparent and transparent conducting substrates. Cyclic voltammetry has been carried out to find out the range of potential of the deposited films. X-ray diffraction shown that the deposited films possess polycrystalline nature. Structural parameters such as crystallite size, strain, dislocation density and stacking fault probability has been determined by the method of Williamson Hall plot analysis. Scanning electron microscopy with Energy dispersive X-ray analysis shown that the deposited films exhibited smooth surface with well defined stoichiometry. Ultraviolet Visible spectroscopic measurements showed that the band gap value around 2.84 eV for the deposited films.

Comprehensive structural analysis and electrical properties of (Cu, Al and In)-doped SnO2 thin films

The undoped, Cu, Al and In (2 at. %) doped SnO2 thin films are deposited on the glass substrate by spray pyrolysis. The effect of Cu, Al and In doping on the structural properties of SnO2 films are investigated by X-ray diffraction (XRD) method. All structural parameters including crystallite size, lattice strain, stress and energy density values are determined from three different models based on Williamson-Hall (W-H) and size-strain plot (SSP) methods. The obtained results reveal that strain values are almost the same but crystallite size, stress and energy density values of the films are greatly affected by dopant atoms. Surface morphologies are analyzed using atomic force microscopy (AFM) measurements. The electrical properties are investigated by Hall effect measurements at room temperature. The number of valance electrons of dopant atoms are less than Sn, as a result the decrement in electrical conductivity and the compensation of n-type conductivity are observed.

Annealing effect on bandgap energy and photocatalytic properties of CeO2–SiO2 nanocomposite prepared by sol-gel technique

CeO2–SiO2 nanocomposites were prepared by sol-gel, a very suitable method for large-scale production. The formation of cubic fluorite structure of CeO2–SiO2 nanocomposites was confirmed by XRD, FTIR and TEM. The average nanocrystalline size has been calculated as 0.5, 1.5 and 2.5 nm using Debye-Scherrer formula for different annealed samples. The calculated nanocrystalline sizes were compared with Williamson-Hall plot and TEM histograms. The FTIR spectroscopy provides the valuable information and identification of different chemical group/bonds present in the prepared samples. The absorption spectra and corresponding band gap energies emphasized a red shift with annealing. The photocatalytic activity was studied through the degradation of Rhodamine 6G under visible light exposure. The nanocomposite annealed at 900 °C has the highest photocatalytic efficiency may be due to small band gap energy. Effect of annealing on mechanism of photodegradation has been discussed in detail. It seems that the crystallinity of the nanopowder is responsible for its higher efficiency because of increase in oxygen vacancies and defect states with annealing which causes narrow bandgap.

Crystallite size and microstrain: XRD line broadening analysis of AgSiN thin films

Purpose This paper aims to determine the crystallite size and microstrain values of AgSiN thin films using potential approach called approximation method. This method can be used as a replacement for other determination methods such as Williamson-Hall (W-H) plot and Warren-Averbach analysis. Design/methodology/approach The monolayer AgSiN thin films on Ti6Al4V alloy were fabricated using magnetron sputtering technique. To evaluate the crystallite size and microstrain values, the thin films were deposited under different bias voltage (−75, −150 and −200 V). X-ray diffraction (XRD) broadening profile along with approximation method were used to determine the crystallite size and microstrain values. The reliability of the method was proved by comparing it with scanning electron microscopy graph and W-H plot method. The second parameters’ microstrain obtained was used to project the residual stress present in the thin films. Further discussion on the thin films was done by relating the residual stress with the adhesion strength and the thickness of the films. Findings XRD-approximation method results revealed that the crystallite size values obtained from the method were in a good agreement when it is compared with Scherer formula and W-H method. Meanwhile, the calculations for thin films corresponding residual stresses were correlated well with scratch adhesion critical loads with the lowest residual stress was noted for sample with lowest microstrain and has thickest thickness among the three samples. Practical implications The fabricated thin films were intended to be used in antibacterial applications. Originality/value Up to the knowledge from literature review, there are no reports on depositing AgSiN on Ti6Al4V alloy via magnetron sputtering to elucidate the crystallite size and microstrain properties using the approximation method.

Antibacterial efficacy of green synthesized α-Fe2O3 nanoparticles using Sida cordifolia plant extract

The aim of the work is to synthesize iron oxide (α-Fe2O3) nanoparticles using Sida cordifolia plant extract along with evaluation of its antibacterial activity. The presence of phytochemicals in Sida cordifolia methanolic plant extract was investigated by HPTLC and LC-MS/TOF. The probable mechanism for formation of α-Fe2O3 nanoparticles in mediation with plant extract was demonstrated. The green synthesized iron oxide nanoparticles (α-Fe2O3 NPs) were characterized by using X-ray diffraction, scanning, and transmission electronic microscopy, TG-DTA, FTIR, and UV spectroscopy. The crystallite size of prepared α-Fe2O3 nanoparticles estimated via Debye-Scherrer formula and Williamson-Hall plot was around 20 nm which is in accordance with particle size in TEM images. The S. cordifolia mediated iron-oxide nanoparticles (α-Fe2O3 NPs) hold potent antibacterial activity against various gram positive and gram negative bacteria.

Effect of Flux Boric Acid (H3BO3) on Yttrium Silicate Y2SiO5:Dy3+ (9 mol%) Nanophosphors Its Characterization and Luminescence Studies

Flux Boric acid (H3BO3) doped on Y2SiO5:Dy3+ phosphors were synthesized by auto ignition based low temperature Solution Combustion Synthesis (SCS) using Oxalic acid dihydrate (ODH) as fuel. Powder X-ray diffraction (PXRD) patterns confirm the nano sized particles corresponding to JCPDS card 36-1476. The crystallite size of the samples estimated from Scherer's formula and Williamson-Hall (W-H) plots was found to be in the range ˜21 nm and 26 nm respectively. Scanning electron Microscope (SEM) micrographs infer addition of flux gives the enhanced grain growth and it attains smooth surface improves the crystallinity and particle morphology of the sample. Fourier transform Infrared (FTIR) data reveals the presence of M–O bonds and Y–O bonds and also the bands at 642 cm–1, 655 cm–1, 668 cm–1, 697 cm–1, 719 cm–1 are ascribed due to the B–O–B linkage in the borate network. Addition of flux on Thermoluminescence (TL) glow curves from 0.5 KGy–4 KGy acts as a sensitizer and the peak appearing at 185 °C is quite stable and can be named as "dosimetric peak" to use in TL phosphor. The kinetic parameters estimated by Chen's peak shape method was found to be second order with activation energy 0.82.

A New Explanation for the Effect of Dynamic Strain Aging on Negative Strain Rate Sensitivity in Fe-30Mn-9Al-1C Steel.

In this study, the evolution of the mechanical properties of Fe–30Mn–9Al–1C steel has been determined in tensile tests at strain rates of 10−4 to 102 s−1. The results show that the strain rate sensitivity becomes a negative value when the strain rate exceeds 100 s−1 and this abnormal evolution is attributed to the occurrence of dynamic strain aging. Due to the presence of intergranular κ-carbides, the fracture modes of steel include ductile fracture and intergranular fracture. The values of dislocation arrangement parameter M were obtained using a modified Williamson–Hall plot. It has been found that once the strain rate sensitivity becomes negative, the interaction of dislocations in the steel is weakened and the free movement of dislocation is enhanced. Adiabatic heating promotes the dynamic recovery of steel at a high strain rate.

Effect of pH on the crystallite size, elastic properties and morphology of nanostructured ZnS thin films prepared by chemical bath deposition technique

Zinc Sulphide thin films have been fabricated on glass substrate via chemical bath deposition technique using zinc acetate, thiourea as the precursor of zinc and sulfur and ammonia for varying pH. The X-Ray diffraction patterns indicate the nanocrytalline nature of the films with broadening of diffraction peaks. Effective Mass Approximation, Scherrer Method and Williamson-Hall plots have been employed for determining crystallite size. The calculated crystallite sizes correlate well with the estimated crystallite sizes from High Resolution Transmission Electron Microscopy images. The HRTEM images show clear lattice fringes of nanocrystallites overlapping each other with random orientations. The elastic properties such as lattice strain, stress and energy density of ZnS thin films have been calculated from the modified form of Williamson-Hall analysis namely Uniform Deformation Model, Uniform Stress Deformation Model, and Uniform Deformation Energy Density Model. The Scanning Electron Microscope images indicate the granular texture of synthesized ZnS thin film at pH 9.6 and coagulation of granules into larger one with increase of pH. The results reveal the obvious effect of ammonia concentration on the optical properties, crystallite size, elastic properties and morphology of the surface of the films.

Multi metal oxide NiO-CdO-ZnO nanocomposite–synthesis, structural, optical, electrical properties and enhanced sunlight driven photocatalytic activity

In this article, ternary oxide NiO-CdO-ZnO nanocomposite along with pure NiO, CdO and ZnO were prepared by the homogeneous co-precipitation method. The XRD pattern confirmed the formation of nanocomposite with NiO (cubic)–CdO (cubic)–ZnO (hexagonal). The volume fractions were 38% NiO, 6% CdO and 56% ZnO phase in nanocomposite determined by direct comparison method. Crystallite size and lattice strain were calculated using Scherrer plot, Williamson-Hall and Size-Strain plot methods. The UV–vis was used to study optical properties such as bandgap (Eg), refractive index (n), extinction coefficient (k), optical conductivity (σopt) and dielectric constants (εr, εi). FTIR and Raman analyses have confirmed the successful formation of NiO-CdO-ZnO nanocomposite. The current-voltage measurements revealed that nanocomposite has high electrical response. SEM images shown that nanocomposite has roughly spherical morphology and EDX described that Zn has higher concentration than Ni and Cd. PL spectra of nanocomposite demonstrated the emission bands associated with new energy levels induced by defects. The photocatalytic activity of grown nanocomposite against rhodamine B (RhB) and methylene blue (MB) dyes under sunlight revealed high degradation efficiency 99% for RhB and 98% for MB in 60 and 90 min illumination respectively, indicated that grown nanocomposite is a propitious sunlight-driven photocatalyst to eliminate organic toxins.

DSC analysis on AA2219 plates processed by cryorolling and coldrolling

Phase transformation in AA2219, is essential in order to understand its strength enhancement especially through precipitation. In this study, Differential scanning calorimetry studies were conducted at different heating rates on AA2219 plates rolled at cryogenic and cold rolling to characterize the reactions that take place in the rolled material. The precipitates evolved at different temperatures were identified and energy stored during the rolling process was also calculated. Cryorolled material showed higher stored energy and therefore enhanced precipitation kinetics compared to the cold rolled sample. The activation energy for precipitation and dislocation density under different conditions were determined from Kissinger and Williamson Hall plots respectively. The lower activation energy for the precipitate formation and the excess dislocation density exhibited by the cryorolled samples are identified as the cause for their superior precipitation kinetics.

Bismuth-substituted hydroxyapatite ceramics synthesis: Morphological, structural, vibrational and dielectric properties

New hydroxyapatite (HAp) ceramics substituted with 10, 30 and 50 at.% of bismuth were synthesized by conventional solid state reaction at high temperature T = 1300 °C, and characterized via X-ray diffraction, scanning electron microscopy, Fourier transform infrared and Raman spectroscopies; dielectric properties were also investigated. The hydroxyl groups observed in infrared spectra confirmed the HAp phase in the studied samples. The crystallite size was estimated by Scherrer's formula and the Williamson–Hall plot, while lattice parameters and the unit cell volume of the samples were measured according to Bi content.Scanning electron microscope images revealed the presence of grains with irregular sizes developed within larger aggregations. Measured relative dielectric permittivity and dielectric loss are slightly affected by Bi content, while the alternating current conductivity increases with a rise frequency, and decreases at increasing of Bi content. The HApBi50% sample presents the optimal dielectric properties.