Williamson-Hall Plot Method Research Articles

Facile combustion-synthesis, structural, morphological, vibrational, photoluminescence, dielectric, and electrical properties of ZnFe2O4 nanostructures: an effect of citric acid concentrations

In the current report, we have facilely synthesized the ZnFe2O4 nanoparticles (ZFO NPs) using the flash combustion route at 600 °C with various concentrations of citric acid (CA). The structural, vibrational, and elemental/homogeneity analyses through XRD, Raman, and energy dispersive X-ray spectroscopy/Scanning electron microscopy e-mapping confirmed the cubic phase and composition of synthesized ZFO NPs. The crystallite size was estimated using Scherrer and Williamson-Hall plot methods and noticed to be reduced with an increasing amount of CA in ZFO and found between 15 and 30 nm, which was also supported by scanning electron and transmission electron microscopic studies. X-ray photoelectron spectroscopy analysis confirmed the synthesis of ZnFe2O4. The ZFO NPs were excited at 417 nm to record the luminescence spectra and found the emission peaks at 456±2, 530±3, and 625±5 nm. The dielectric constant was found to be between 147 and 165 with low loss values, and the electrical conductivity was found to be enhanced with CA content in ZFO NPs. The magnetic properties were also studied at 300 K and disused. These outcomes indicate that the properties of ZFO NPs have been greatly influenced by crystallite/grain size variation, which resulted from different CA concentration-assisted synthesis of ZFO and possess the potential for optoelectronic and energy storage devices.

Piezoelectric, structural, vibration and optical properties of lead free based 0.5Ba(Ti0.8Zr0.2)O3-0.5(Ba0.7Ca0.3)TiO3 ceramic sample

The single-phase solid solution of 0.5 {Ba (Zr0.2Ti0.8) O3}− 0.5 {(Ba0.7Ca0.3) TiO3} ceramic sample was prepared by solid state method. The X-ray diffraction study confirmed the mixed phases of tetragonal and rhombohedral crystal structure. The average crystallite size was ∼ 90 nm measured from the Williamson Hall plot method. An estimated average grain size ∼ 4.2 µm is obtained from scanning electron microscopy and well-defined grains separated by clear grain boundaries. The band gap for the sample was found ∼2.8 eV from absorption spectra. The red shifting of vibration B1/E(TO3)/E(LO2) mode at low temperature causes the phase transition from tetragonal to rhombohedral and the band E(TO)+A1(TO) at ∼523 cm−1 becomes more broadening and disappears above 300 °C. So sample transfer from tetragonal to cubic phase. The absence of A(LO1) and the softening of A(TO3) modes are attributed to transfer from tetragonal to rhombohedral above − 100 °C at low temperature. The temperature dependence of permittivity value further supports the phase transition from orthorhombic-tetragonal ∼50° C and tetragonal–cubic ∼ 250 °C. The PL spectra revealed disorder and three distinct green peaks (2.85 eV, 2.75 eV, 2.65 eV and 2.54 eV) evidence of rhombohedral structure. P∼E loop exhibits a soft and ferroelectric in nature. A maximum strain of 0.45% field-induced and a large d33 value ∼ 870 pm/V in the ceramics sample.

Radio-frequency controlled crystalline phase transformation of MoS2 thin film fabricated by unique vapour-plasma mixing technique

Successful fabrication of molybdenum disulfide thin films on silicon substrates by a unique vapour-plasma mixing technique at a relatively low temperature of 300 °C is reported. This mixing technique involves simultaneous sputtering of a molybdenum target and thermal evaporation of sulphur flakes to form MoS2 molecules. Raman studies confirm the formation of MoS2 with characteristic E12g and A1g modes observed at ∼384 and ∼408 cm−1. The effects of radio frequency (RF) power on the physical properties of MoS2 film at a constant sulphur evaporation rate are investigated. The Raman and X-Ray photon spectroscopy reveal that a controlled crystalline phase transition between metallic tetragonal (1 T-MoS2) and semiconducting hexagonal (2H–MoS2) has been successfully achieved upon variation of the RF power. Furthermore in X-Ray diffraction analysis, Scherrer's, Williamson-Hall and Size-Strain Plot methods are used to extract relevant correlations between structural properties (viz. Crystallite sizes, strains) and the thin film growth controlling parameters.

Growth of CuO nanoparticles using one step chemical bath deposition under microwave heating and their characterizations

Abstract Varied morphologies of crystalline copper oxide nanoparticles were synthesized using one step chemical bath deposition under microwave heating of prepared growth solution at 1200 W microwave power for a very short duration of 2–8 min. The structure and crystallinity of the as grown copper oxide nanoparticles were studied by wide angle X-ray diffractometer analysis. The particle size values obtained from Scherrer’s relation and the Williamson–Hall plot methods are in the 16–18 nm range. The approximate size of as grown copper oxide nanoparticles evaluated from field emission scanning electron microscopic images are in the range of approximately 15–20 nm. The presence of copper and oxygen was verified by energy dispersive X-ray spectroscopy analysis. Their weight % and atomic % exhibits the rich amount of development of copper oxide nanoparticles in a 1:1 stoichiometric ratio. The optical properties of as grown copper oxide nanoparticles were examined by assessing absorption spectra of the sample in ultraviolet–visible range. The significant peak of absorption spectra is seen near 340 nm wavelength which explains the mono-dispersion behaviour of nanoparticles. Evaluation of Urbach energy of copper oxide nanoparticles reveals that the nanomaterial has microstructural lattice disorder. These characterizations of as synthesized copper oxide nanoparticles explain the feasibility and potential of such nanomaterial to be incorporated in a wide range of utilities.

Frustrated microstructures composite PbS material’s size perspective from XRD by variant models of Williamson–Hall plot method

Frustrated microstructures composite PbS material’s size perspective from XRD by variant models of Williamson–Hall plot method

Crystal structure determination, XRD peak profile analysis and morphological study of double perovskite SrNdFeTiO6

In this work we have proclaimed the synthesis, structural and morphological characterization of the double perovskite oxide SrNdFeTiO6. The material has been synthesized by conventional solid-state reaction technique. X-ray diffraction pattern and Rietveld refinement results have confirmed that the prepared structure crystallizes in orthorhombic phase. The positions of various elements present in the prepared sample have been corroborated by 2D and 3D electron density maps. Peak profile analysis of this double perovskite was carried out by calculating crystallite size using two different methods viz. Debye-Scherrer equation and Williamson-Hall plot method. Both the methods revealed that the crystallite size is in nanometers, however results differ from each other. Microstructural analysis revealed that the synthesized sample has uniform distribution of grains.

Characterization of PbS nanoparticles synthesized using sodium lauryl sulfate at room temperature

Synthesis of lead sulfide (PbS) nanomaterials was carried out via an anionic surfactant-assisted co-precipitation route at room temperature. The anionic surfactant used in this process was Sodium Lauryl Sulfate (SLS). X-ray diffraction (XRD) was carried out for characterizing the synthesized PbS nanoparticles. Peak broadening analysis was done to investigate crystallite size using Scherrer, Williamson-Hall, modified Scherrer, and Size-Strain method. Uniform Deformation Model (UDM) was assumed to calculate lattice strain for all peaks of XRD data of PbS nanoparticles via the Williamson-Hall plot method. The Size-Strain method was also used to estimate strain more accurately. The surface structures of the synthesized PbS nanoparticles were studied by Scanning Electron Microscopy (SEM). The synthesized PbS sample was also analyzed by Fourier Transform Infrared Spectroscopy (FTIR) to ascertain the phases. It was observed that the Size-Strain method gives the most adequate approximation of average particle size having a diameter of 21.29 nm for PbS synthesized with 0.01 M SLS concentration at room temperature.

Phase transition and optical characteristics of Mg doped CuAlO2 synthesized by facile thermal decomposition process

Phase formation, phase composition and structure analysis are essential in understanding the properties of the mixture. This work presents the phase formation and transition of delafossite CuAlO2 with Mg incorporation (0–10 mol%), prepared by a thermal decomposition synthesis. Due to various operating temperatures and dopant concentrations, the X-ray diffraction (XRD) analysis exhibited a phase difference, observed as CuAlO2, CuAl2O4 and CuO. Pristine CuAlO2 preparation was achieved at a firing of 1200 °C for 6 h. Crystallite size and micro-strain of obtained products were approximated by Williamson-Hall and size-strain plot method. Morphology transformation was examined by scanning electron microscope (SEM), showing a surface roughness change depending on the phase composition. Fourier transform infrared spectroscopy (FT-IR) detected Cu-O and Al-O bonding vibration spectral bands, confirming CuAlO2 formation. The energy bandgap (Eg) was found in the range 3.87–3.98 eV as Mg adding 0–10 mol%. The effect of dopant incorporation and phase transition causes the variation of Eg. Photoluminescence spectroscopy (PL) exhibited the near band-edge emission (NBE) at 311 nm (3.99 eV), observing Mg interstitial defect state at 340 nm (3.65 eV) and deep oxygen defect state at 558 nm (2.22 eV). The optical characteristics associating with the dopant and phase component are also discussed.

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.

Temperature dependent micro strain analysis of Lanthanum oxide nanoparticle using Williamson-Hall and size-strain plot methods

Lanthanum oxide nanoparticles are prepared by chemical co-precipitation method using Lanthanum chloride and Ammonium carbonate as starting materials. DNA and STARCH is used as capping agent to maintain the particle size within the nanometer range. Elemental analysis of the sample is carried out through Energy Dispersive X-ray Analysis (EDAX). The structural characterization is carried out through XRD analysis. To confirm the formation of body centered cubic La2O3NPs, the Rietveld profile matching analysis is also done. The XRD peak broadening due to the intrinsic strain associated with particle size have been investigated using W-H and SSP methods. From the different models in W-H method, the micro structural parameters like strain, stress and energy density are calculated. To understand the temperature dependent nature of the samples, compare the results of the different samples obtained at different annealed temperatures 600 °C, 700 °C and 900 °C.

Evaluation of spectral, optoelectrical, dielectric, magnetic, and morphological properties of RE3+ (La3+, and Ce3+) and Co2+ co-doped Zn0.75Cu0.25Fe2O4 ferrites

Present work reports the synthesis of RE3+ (La3+, and Ce3+) and Co2+ co-doped Zn0.75Cu0.25Fe2O4 samples powder using sol-gel auto combustion process. Rietveld refinement established the spinel matrix with the space group (F d -3 m) and suggests that the uniform distribution of cations at the tetrahedral and octahedral lattice sites. The comparative study of crystallite size (D) was found using the Scherrer's relation, Scherrer's plot, Williamson-Hall (W–H), and Size-Strain (SS) plot methods for the as-prepared ferrites. The absorption band analysis confirmed the characteristic band absorptions lie in the frequency range of (577.82–418.84) 102 × m−1. Moreover, the electrical resistivity (ρ) measurements showed that the Co–Ce doped ZCF sample is highly resistive as compared to the other samples. The dielectric measurements revealed a dispersion pattern at lower frequencies and an almost frequency-independent pattern at higher frequencies. The field dependence of the dM/dH curve shows a magnetically well stable state and good crystallization cubic matrix of all the samples.

Theoretical comparison of lattice parameter and particle size determination of pure tin oxide nanoparticles from powder X-ray diffraction

SnO2 is an n-type semiconductor and a transparent conducting oxide and has apt properties in a gas sensing material, photovoltaic cells, fuel cells, batteries etc., Nanocrystalline tin oxide (SnO2) powders with different grain sizes were prepared by chemical co-precipitation method. Synthesised nanopowder XRD data were analyzed with different tools. X-ray diffraction (XRD) analysis mainly used to determine the crystal structure of nanomaterials such as ZnO, CuO, CdO and SnO2, etc., Pure SnO2 test conditions were set to be Cu-Kα XRD source, accelerating voltage 40 kV, acceleration currency 40 mA, scan range 20–80° with Ni filter (λ = 0.154056 nm). The pure SnO2 sample was exhibiting different crystalline peaks from the powder XRD study. The diffraction peak of pure tin oxide nanoparticles possesses a tetragonal rutile structure with space group P42/mnm. The FULLPROF Suite program was used for Rietveld–type analysis for pure SnO2powder diffraction data. The resultant data were compared with Nelson-Riley, Williamson-Hall plot, and Debye-Scherer methods. The lattice parameters and particle size of pure SnO2were agreed with the ICDD.No.01-077-0447data. The main advantages of these methods are low angle regions and a small number of peaks needed.

Facile in-situ synthesis, microstructural, morphological and electrical transport properties of polypyrrole-cuprous iodide hybrid nanocomposites

In this study, polypyrrole cuprous iodide (PPy-CuI) hybrid nanocomposites were synthesized in an aqueous medium via an in-situ chemical oxidation route with ammonium persulphate as an oxidizing agent to report the microstructural, morphological, and electrical properties of as-synthesized specimens. By using an in-situ oxidative polymerization method, sonochemically synthesized γ-CuI nanocrystals were mixed with a PPy matrix in varying weight percentages (10–40 ​%). The purity, crystallinity and structure of hybrid nanocomposites were determined using X-ray diffractometry. The average crystallite size of hybrid nanocomposites was calculated using the Debye-Scherrer, Williamson-Hall and Size-Strain plot methods. All specimens' intrinsic strain was estimated using the Williamson-Hall plot and the Size-Strain plot methods. The field emission scanning microscopy revealed that the surface morphology changed from granular to overgrown clusters as the weight percent of CuI nanocrystals is increased from 10 to 40 ​% in PPy-CuI hybrid nanocomposites. The Fourier transform infrared spectroscopy indicates the formation of PPy and successful insertion of γ-CuI nanocrystals into the PPy matrix. The room temperature dc electrical conductivity is found to decrease from 6.3 ​× ​10−2 Scm−1 to 1.70 ​× ​10−3Scm−1as the wt% of γ-CuI nanocrystals increases from 10 to 40 ​% in hybrid nanocomposites. Furthermore, the increasing trend of dc conductivity with temperature is due to all samples' semiconducting nature. In the temperature range of 200–300 ​K, the measured experimental data followed the Arrhenius and Mott's 3d variable range hopping (VRH) model. The values of average activation energy, average hopping energy, density of states at Fermi level, average hopping distance and Mott's characteristic temperature of PPy-CuI (40 ​%) hybrid nanocomposites at 300 ​K were estimated to be ~60 ​meV, ~29 ​meV, 6.36 ​× ​1022 ​cm−3eV−1, 5.06 ​Å and 1901 K, respectively.

Structural and spectroscopic analysis of green glowing down-converted BYO:Er3+ nanophosphors for pc-WLEDs

An energy efficient solution combustion technique was selected for fabricating a series of energy-efficient novel down-converted Ba3Y4O9:Er3+ nanoparticles with green emission. Crystal structure engineering along with the morphological aspects was investigated via certain advanced characterizations such as Rietveld refinement and powder X-ray diffractometry (PXRD) procedure, microscopic practices like scanning and transmission electron microscope techniques, photoluminescence and diffuse reflectance spectroscopic analysis. Average crystallite size (65.71 nm–74.15 nm) and micro strain (0.0012) of the optimum powder nanomaterial were analyzed from high quality XRD data using Williamson-Hall (W–H) plot method. Alluring spectroscopic features were realized by photoluminescent (PL) spectra recorded upon excitation via near ultraviolet (NUV) source of 381 nm; displaying an intense emission peak (562 nm) situated in the visible region that is solely responsible for the green glow of the prepared phosphor. PL analysis witnessed a bright green emission via a reliable emanation transition (4S3/2 → 4I15/2) of Er3+ ions. Excellent colorimetric parameters of optimized nanophosphor like CIE coordinates (0.3420, 0.6064), 5356K CCT and 79.02% color purity validated its advanced photonic and optoelectronic applications for cool light emitting WLEDs, lasers, optical sensors, solar and photovoltaic cells.

X-Ray Peak Profile Analysis of Materials M1 and M2 by Williamson-Hall and Size-Strain Plot Methods

In this work, we have studied the Kaolin M1 and M2 by the X-ray diffraction method, and we have focused on mullite phase which is the main phase present in common in both products. An update of the program of the method of Stokes was carried out, it was necessary to the microstructural analysis. The completed version is less sensitive to the choice by excess of the number of coefficients of Fourier with regard to the effect of truncation and the office plurality of the errors. The determination of the symmetry of the cell of the principal phase (mullite) in the studied fritted Kaolins was carried out. In Kaolin M1, the size of crystallites of the dominant phase varies between 80 to 170 Å. In Kaolin M2, the size of the crystalline grains of mullite varies between 100 to 400 Å. The size of crystallites was confirmed by the joint method of Williamson-Hall. A distribution of sizes of crystallites was carried out. It shows a dominance of the size of approximately 140 Å for the principal phase of Kaolin M1 and a dominance of the size of approximately 230 Å for the same principal phase of Kaolin M2. By the study of the profiles of line by DRX, it appears very clearly that the principal phase of the various sintered Kaolins, mullite, is free from internal microstrains. It is the case of the mixtures fritted not only at low temperature (1100℃) during 1 hour but also the case of the mixtures of the type ‘chamotte’ cooks with 1350℃ during very long times.

Sequel of divalent zinc substitution on structural, electrical and thermal properties of bismuth ferrite ceramics

Polycrystalline ceramic samples of BiFe1−xZnxO3 (x = 0.00 and 0.05) have been prepared by sol–gel synthesis method. The formation of the compound has been checked by the X-ray analysis and confirmed the observed data by matching with the standard data (ICSD-97591). The Rietveld analysis confirmed the rhombohedral symmetry with space group R3c. The average crystallite size calculated by the Scherrer method is well matching with that calculated by Williamson–Hall plot method and is of the order of nanometre range. The two- and three-dimensional surface morphology has been measured using atomic force microscopy. The dielectric parameters, including dielectric constant, impedance, etc., have been measured and explained using the universal dielectric response model. The electrical modulus study explains the transport behaviour of the materials. The activation energies calculated by the dc conductivity measurement and the I–V characteristics indicate that both the materials show semiconducting behaviour. Thermal analysis has been used to check the high temperature phase transition and thermal stability of the materials. The room temperature FTIR spectra measured in the fingerprint region (750 cm−1 to 400 cm−1) explains the molecular symmetry of the materials. All the results have been discussed in detail.

Facile synthesis and characterization of conducting polymer-metal oxide based core-shell PANI-Pr2O–NiO–Co3O4 nanocomposite: As electrode material for supercapacitor

Metal oxide nanoparticles and their composites with conducting polymers, specifically Polyaniline (PANI) were utilized for fabricating nanoscale supercapacitor (SC) electrode materials. In the present study, we have synthesized pristine Pr2O3, NiO, Co3O4 nanoparticles, binary PANI-Pr2O3, PANI-NiO, PANI-Co3O4, ternary Pr2O3–NiO–Co3O4, and quaternary PANI-Pr2O3–NiO–Co3O4 spherical core-shell nanocomposite using co-precipitation and ultra-sonication methods. The grown samples were characterized with different analytical techniques. The XRD pattern revealed that the as-synthesized products were crystalline with Pr2O3 hexagonal phase, NiO cubic phase, and Co3O4 cubic phase in pure and nanocomposites. The Williamson-Hall, Scherrer, and size-strain plot methods were employed to study the crystalline development and contribution of micro-strain. FTIR pattern exhibited the metal-oxygen and PANI bond vibrations. FE-SEM images shown the spherical core-shell shape morphology of quaternary nanocomposite. EDX evident the presence of praseodymium, cobalt, and nickel in synthesized samples. UV–vis spectroscopy confirmed the absorption in the visible region. The IV graphs showed a higher conductivity of quaternary nanocomposite. The cyclic voltammetry results revealed that the quaternary nanocomposite has a higher specific capacitance 500 Fg-1 as compared to binary nanocomposites 134 F g−1 (PANI-Pr2O3), 143 F g−1 (PANI-Co3O4), 256 F g−1 (PANI-NiO), and PANI (90.8 F g−1) at a scan rate of 5 m Vs−1. The GCD results also showed that the quaternary nanocomposite has a higher specific capacitance of 905 F g−1 at current density 1 A g−1 with maximum energy density and power density of 87.99 kWhkg-1 and 2.6 k W kg−1, respectively. The EIS curve also confirmed that the quaternary nanocomposite has a lower polarization resistance (Rp) and solution resistance (Rs). The higher capacitance of quaternary nanocomposite can facilitate ion transfer, and the formation of its core-shell structure flourish to enhance surface-dependent electrochemical properties. Furthermore, this study gives a novel research idea to manufacture electrode materials for supercapacitors.

Room temperature multiferroic properties of BiFeO3–MnFe2O4 nanocomposites

The novel functionalities of multiferroic magneto-electric nanocomposites have spawned substantial scope for fast-paced memory devices and sensor applications. Following this, herein we report the development of nanocomposites with soft ferromagnetic MnFe2O4 and ferroelectric BiFeO3 to fabricate a system with engineered multiferroic properties. A modified sol-gel route called Pechini method is demonstrated for the preparation of the (1-x) BiFeO3-x MnFe2O4 (x = 10%, 30%, 50%, 70%) nanocomposites. The crystallographic phase, structure, and morphology are characterized by XRD, FESEM, and HRTEM. The accurate crystallite size and lattice strain are determined by Williamson-Hall plot method and a comparative study with Scherer's equation is carried out. TEM image evidences the interface between BiFeO3 and MnFe2O4 nanoparticles in the composite. The room temperature magnetic response reveals the strong dependence of magnetic saturation, remanent magnetization, and coercivity of the nanocomposites on MnFe2O4 addition. The dielectric response and impedance analysis of the prepared nanocomposites are observed. The electrical performance of the composite is affected by grain, grain boundaries, and oxygen vacancies. The unsaturated P-E loops exhibit the leaky ferroelectric behavior for the nanocomposite. The intrinsic magnetoelectric coupling between ferroelectric BiFeO3 and ferromagnetic MnFe2O4 has been determined by varying Hdc/Hac and its maximum coupling coefficient (α) is found to be 25.39 mV/cmOe for 70% BiFeO3 -30% MnFe2O4 nanocomposite. These distinctive and achievable characteristics of the nanocomposite would enable the designing of magnetic field sensors, spintronic devices, and multiferroic memory devices.

Multiferroic Bismuth ferrite nanocomposites as a potential photovoltaic material

Bismuth ferrite (BFO) is one of the few materials which is multiferroic (antiferromagnetic and ferroelectric) at 25°C. In this work, we synthesized multiferroic BFO via sol-gel method and observed its structural and optical properties. While synthesizing BFO, the annealing temperature was at 550°C. X-ray diffraction (XRD) analysis exhibited a rhombohedral crystal structure. Rietveld refinement via MAUD software has been employed to obtain the structural parameters of BFO. Williamson-Hall (W-H) plot method is used to analyze the XRD data. We obtained crystallite size of 37.61 nm through W-H plot analysis. Using the crystallographic information file, we measured the bond angle and bond length of BFO nanoparticles. BFO nanoparticles with both uniform distribution and spherical shape was observed in Field Emission Scanning Electron Microscopy (FESEM). The average particle size of 157 nm was measured from FESEM analysis. The atomic % of Bismuth (Bi), Oxygen (O) and Iron (Fe) elements in BFO was obtained from Energy dispersive spectroscopy. The optical bandgap energy (Eg) of BFO was calculated using UV-Vis-NIR, and we found the bandgap energy of 2.04 eV for BFO annealed at 550°C. This bandgap energy makes BFO a potential photovoltaic material.

Structural, morphological, and magnetic study of low temperature synthesized Co0.75Ni0.25Fe1.95Dy0.05O4 nano ferrite

The nanoparticles of Co0.75Ni0.25Fe2−zDyzO4 (z = 0.0 and 0.05) were prepared by the sol-gel auto-combustion method. The cation distribution was calculated from the Rietveld refinement of the XRD pattern to confirm a mixed inverse spinel structure. The crystallite size was calculated by the Debye–Scherrer method, modified Scherrer method, Williamson Hall plot method, and size-strain plot method for prepared samples. The variation in crystallite size was observed due to the contribution of lattice strain on line peak broadening. From Fourier transform infrared (FT-IR) spectrum the absorption bands appeared at 574.79 cm−1 and 414.70 cm−1 reveals spinel ferrite structure for Co0.75Ni0.25Fe1.95Dy0.05O4. The particle size from a high-resolution scanning electron microscope (HR-SEM) the image was found to be 46.99 nm for Co0.75Ni0.25Fe1.95Dy0.05O4. Energy-dispersive X-ray spectrum (EDS) was confirmed the purity of the sample with good stoichiometry. The coercivity, retentivity, and saturation magnetization were estimated at 841.97 Oe, 30.95 emu g−1 and 61.80 emu g−1 respectively for Co0.75Ni0.25Fe1.95Dy0.05O4. The squareness ratio for Co0.75Ni0.25Fe1.95Dy0.05O4 nanoferrite was found to be 0.5 which is the ideal Stoner—Wohlfarth value. The experimental estimated net magnetic moment () per formula was less than the theoretical value calculated from Neel’s two sublattice model for prepared samples.