Quantitative analysis of diffraction and infra-red spectra of composite cement/BaSO4/Fe3O4 for determining correlation between attenuation coefficient,structural and optical properties

To better understand the structural and optical properties of composite cement/BaSO₄/Fe₃O₄ for various amount of BaSO₄/Fe₃O₄, the X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy have been used to investigate the correlation between their structural and optical properties. The structural properties including crystallite size, micro strain, stress and energy deformation were analyzed from the quantitative analysis of XRD spectra by using size-strain plot (SSP) methods. The refractive index (n), extinction coefficient (k), dielectric functions (ε), and energy loss function (Im (−1/ε)) were analyzed from the quantitative analysis of FTIR spectra by using kramers-kronig (K–K) relations. The corresponding structures for high amount of BaSO₄/Fe₃O₄ in composite cement/BaSO₄/Fe₃O₄ become less stable which consistent with the distance between the wavenumber of transversal and longitudinal optical phonon vibration mode become shorter. For all composites cement/BaSO₄/Fe₃O₄ in this study, we found that the distance wavenumber (Δ) between longitudinal optical (LO) and transversal optical (TO) phonon vibration decrease with increasing the crystallite size and linear attenuation coefficient. Our results indicated that the FTIR spectra could be useful for determining the optical phonon vibration, dielectric function, and energy loss function of composite cement/BaSO₄/Fe₃O₄.     

Four-phases characterization of synthesised CeO2 thin films: Effect of molarity on structural,optical, physical properties and gamma-ray attenuation parameters

A group of novel CeO₂ thin films were synthesised using ultrasonic spray pyrolysis process. The composition ratios of these films were modified to investigate changes in their optical, surface, electrical, and structural characteristics. Absorbance spectra in the range 300–900 nm was acquired. Transmittance in the visible area was determined to be 50%. The optical band gap was reported to vary between 3.38 and 3.52eV using absorbance spectra. X-ray diffraction was used to analyse the films' structure, while atomic force microscopy was used to determine the surface roughness values. Spectroscopic ellipsometry and the Cauchy–Urbach model were used to calculate the thicknesses. Electrical resistivity values were determined using a four-probe system. CeO₂ thin film X-ray diffraction patterns validated the polycrystalline cubic fluorite structure. According to the data, the deposited films expand preferentially in the (2 0 0) direction. The films were found to have a high resistivity of 10⁶ Ω cm. We also evaluated the nuclear radiation shielding properties of CeO₂ thin films in the 0.015–15 MeV photon energy range. The results indicated that CeO₂ thin film exhibits promising half value layers of 0.00169 cm, 0.14055 cm, 1.62665 cm, and 2.30273 cm, respectively, for 0.015 MeV, 0.15 MeV, 1 MeV, and 15 MeV CeO₂ films have been determined to be worth working on and may be promising materials for optoelectronic and nuclear security applications.     

Structural,magnetic and optical properties of Ce substituted BiFeO3 nanoparticles

Ce substituted Bi_1−xCe_xFeO₃ (x=0.03, 0.05, 0.07 and 0.10) nanoparticles were prepared by a tartaric acid based sol–gel route. X-ray diffraction patterns and Raman spectra revealed a structural phase transition from rhombohedral to orthorhombic phase for x=0.10 sample. Room temperature magnetic measurements showed weak ferromagnetic ordering and enhancement in magnetization with increasing Ce concentration. The improved magnetic properties due to the breaking of spin cycloid with Ce substitution have been observed from electron spin resonance (ESR) study. The measured g-values for all samples are greater than 2 and the ESR lines shift towards higher g-value with increasing Ce concentration, indicating ferromagnetic nature of these samples. UV–visible diffuse reflectance spectra showed a sharp absorption in the visible region with two d–d and three charge transfer (C-T) transitions. Prominent red shift in the band gap indicates a significant change in the band structure of the doped nanoparticles.     

The role of Pb and annealing temperature on the structural,magnetic, optical and dielectric properties of W-type hexaferrite nanostructures

In this paper, W-type Sr_1-xPb_xCo₂Fe₁₆O₂₇ nanostructures were synthesized by auto-combustion sol-gel method. Then, the effects of annealing temperature and Pb contents on the structural, magnetic, optical, and dielectric properties of Sr_1-xPb_xCo₂Fe₁₆O₂₇ nanostructure were investigated. First, a gel of metal nitrates with a specific molar ratio with x different was prepared and then the gel was annealed at different temperatures for 4?h. To determine the annealing temperature of the samples, the prepared gel was examined by thermogravimetric analysis and differential thermal analysis. The morphology and crystal structure of the prepared samples were characterized by field emission scanning electron microscopy (FESEM) and X-ray diffraction pattern (XRD). The results of XRD patterns indicated that the annealing temperature of synthesized Sr_1-xPb_xCo₂Fe₁₆O₂₇ was reduced by increasing Pb contents. In addition, FESEM images showed that the microstructure of the samples was homogeneous and uniform, but since the samples have a magnetic property, the particles were aggregated. Fourier transform infrared analysis (FT-IR) was used to confirm the phase formation. The FT-IR results of the samples indicated that the tetrahedral and octahedral sites, which are the important attributes of hexaferrites, were formed. The magnetic properties of the samples were measured by vibrating sample magnetometer (VSM). The VSM results of the samples showed that because of increasing Pb content, the amount of saturation magnetization and that of magnetic coercivity decreased from 81.29 to 10.23?emu/g and 2285–477?Oe, respectively. The optical properties of the samples were investigated by ultraviolet–visible spectroscopy, which revealed that the energy gap decreases and the absorption peaks move towards longer wavelengths by increasing Pb content. The dielectric properties of the samples were investigated by the LCR meter. It was found that by increasing frequency, the dielectric constant (ε^′) and the dielectric loss (?) of the samples were decreased.     

Effect of calcination temperature on structural and morphological properties of bismuth ferrite nanoparticles

Bismuth Ferrite (BiFeO3) is one such materials which has shown very promising multiferroic and excellent optical properties. In this paper, we report effect of annealing temperature on the structural, morphological and optical properties of BiFeO₃ nanoparticles synthesised through sol-gel auto-combustion method. Nanoparticles prepared were calcined at three different temperatures, 400 °C, 500 °C and 600 °C, and named as BFO1, BFO2 and BFO3, respectively. X-ray diffraction confirmed the rhombohedral structure with R3c space group as a primary phase. However, a secondary phase Bi₂Fe₄O₉ was also observed which decreases with increasing temperature. The crystallite sizes were found to increase with increasing temperature with BFO2 as anomaly. Field emission scanning electron microscopy (FESEM) shows clear grain formation for all the samples. TEM micrographs and SAED patterns show crystalline grains with rhombohedral structure. All the functional groups observed in the Fourier infrared spectroscopy (FTIR) measurement are indexed. The FTIR spectra shows presence of two prominent vibrational modes in the wave number range 447 and 560 cm^-1 corresponding to the stretching of Fe-O bonds. Raman analysis shows presence of a peak at ~527 cm^-1 for (BFO3) which was absent in other two samples. Also, the intensity of the A₁-1 mode was found stronger than that of A₁-2 mode in all the samples which confirmed the stability of the structure, except for BFO1.     

X-ray diffraction (XRD) profile analysis and optical properties of Klockmannite copper selenide nanoparticles synthesized via microwave assisted technique

In this study, copper selenide (CuSe) nanoparticles (NPs) were prepared using the microwave irradiation technique. The effect of the irradiation time on the structural properties of CuSe NPs was investigated. The XRD results confirms the formation of the hexagonal (Klockmannite) structure of CuSe NPs. Different X-ray diffraction profile analysis techniques comprising strain-size plot (SSP), Scherer’s method (S-M), Monshi-Scherer’s method (MSM), Halder-Wagner (H–W) technique, and Williamson-Hall technique (WHM) were employed to examine the effect of irradiation time on the particle size as well as intrinsic strain of CuSe NPs using XRD peak broadening analysis. Uniform deformation model, uniform stress deformation model, as well as uniform energy density deformation model of Williamson-Hall technique were used to calculate the average crystallites size of CuSe NPs. Essential physical variables involving stress and energy density were also computed. Also, field emission scanning electron microscope (FESEM) in addition to atomic force microscopy (AFM) were further used to determine the mean particle size of CuSe NPs depending on varying irradiation time. The obtained results were found to be in agreement and comparable with the results of XRD profile analysis methods. Raman spectroscopy revealed three vibrational bands which are ascribed to the CuSe vibrational modes. Furthermore, the optical characteristics of the synthesized CuSe NPs were also investigated. The result obtained revealed a decrease in the optical bandgap from 2.43 to 2.71 eV with increase in irradiation time. Photoluminescence study revealed two peaks at 530, and 610 nm respectively. Therefore, it can de deduced that inclusion of intrinsic strain play an important role on the estimation of CuSe NPs size and microstrain of CuSe NPs synthezed vi microwave assisted synthesis technique.     

Influence of high energy ball milling on structural,microstructural and optical properties of TiO2 nanoparticles

The influence of high-energy ball milling on structural, microstructural, and optical properties of TiO₂ by modifying the nanoparticle size was studied. Five samples were extracted at different milling times (0, 2, 4, 8, and 13 h). The average particle sizes estimated by dynamic light scattering (DLS) were 205, 155.8, 116.8, 82.9, and 82.7 nm at 0, 2, 4, 8, and 13 h, respectively. X-ray diffraction analysis confirmed progressive broadening of the peaks as the milling time elapsed. Besides, a correlation was found between d spacing and the average crystal size. The UV–Vis diffuse reflectance spectra of TiO₂ revealed a decrease in reflectance due to particle size reduction. Similarly, an alteration of the bandgap transition energy was presented, whose values gradually decreased from 2.966 eV to 2.861 eV for the sample without and with the maximum duration milling performed (13 h), respectively. Likewise, the SEM analysis showed a distribution in nanoparticle size that became more homogeneous and smaller average grain size as the milling duration was longer.     

Facile synthesis and optical properties of polymer-laced ZnO-Au hybrid nanoparticles

Bi-phase dispersible ZnO-Au hybrid nanoparticles were synthesized via one-pot non-aqueous nanoemulsion using the triblock copolymer poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) as the surfactant. The characterization shows that the polymer-laced ZnO-Au nanoparticles are monosized and of high crystallinity and demonstrate excellent dispersibility and optical performance in both organic and aqueous medium, revealing the effects of quantum confinement and medium. The findings show two well-behaved absorption bands locating at approximately 360 nm from ZnO and between 520 and 550 nm from the surface plasmon resonance of the nanosized Au and multiple visible fingerprint photoluminescent emissions. Consequently, the wide optical absorbance and fluorescent activity in different solvents could be promising for biosensing, photocatalysis, photodegradation, and optoelectronic devices.     

Improved optical and structural properties of cadmium sulfide nanostructures for optoelectronic applications

In this study, the effect of ZnO seed layer on the growth of uniform CdS nanostructures was investigated using chemical bath deposition technique. Besides, the influence of molar concentration of reagents on the surface morphology, structural and optoelectrical properties of the deposited CdS thin films were examined. The CdS nanostructures were grown on bare glass and ZnO/glass substrates with different reagent molar concentrations. The results indicated an improvement in the homogeneity and uniformity of the grown CdS nanostructures on ZnO seed layer which can be due to the low lattice mismatch between ZnO and CdS structures. The CdS/ZnO samples were optimized by changing the molar concentration of reagents. A three–dimensional intersecting vertical nanosheet morphology with hexagonal structure was obtained when modified chemical concentration of 0.5 M was applied. The XRD pattern of CdS nanosheets indicated the hexagonal phase of CdS which were strongly orientated along (002) plane. The elevated intensity of dominant peak related to this sample confirmed the improved crystal quality of this CdS nanostructure comparing to the other samples. The UV–Vis spectrum demonstrated a high absorption coefficient for CdS intersecting nanosheets which might be due to the high specific surface area and light trapping behavior of this sample. The photoluminescence study also showed an improvement in optical properties of optimized CdS nanostructures. In order to study the optoelectrical properties of CdS nanostructures, metal–semiconductor–metal photodetectors were fabricated with different CdS samples and their current–voltage characteristics were analyzed. The results indicated an enhancement in photosensitivity, responsivity, and speed of photodetectors based on optimized CdS nanostructures.     

Enhancement of optical,dielectric and transport properties of (Sm,V) co-doped ZnO system and structure-property correlations

In this work, V-doped and (Sm, V) co-doped ZnO samples have been synthesized using ball milling method followed by heat treatment. The dependence of structural, optical, electrical and dielectric properties of V:ZnO samples on the Sm doping concentration has been explored. The structural properties have been studied by means of X-ray diffraction (XRD) and Rietveld refinement. Oxidation states of the elements present in the samples are determined using X-ray photoelectron spectroscopy. Raman spectra of the samples further verified the observations obtained from XRD. The crystallite size and microstrain have been estimated from the Williamson-Hall analysis. Microstrain increases from 0.814 × 10^?3 to 1.01 × 10^?3 with increase in the Sm doping level. The morphology of the grains is significantly affected by the Sm doping. The enhancement of defect density with Sm doping is responsible for the observed red shift (3.29–3.19 eV) in the band gap. The frequency dependence of the dielectric properties has been studied at various fixed temperatures ranging from 25 to 350 °C. The increase in real dielectric constant with dopant content indicates the enhancement of energy storage capacity. The ac conductivity follows Jonscher's power law and it increases up to 1 mol% Sm concentration. Further increase in Sm extent leads to the decrease in ac conductivity. The impedance spectroscopy has been performed to understand electrical behavior of samples and Cole-Cole plots are fitted against the equivalent circuit model. The electrical activation energy values for conduction and relaxation vary in the range: 0.281–0.269 eV and 0.260–0.243 eV, respectively.     

Effect of Gd doping on structural,optical properties,photoluminescence and electrical characteristics of CdS nanoparticles for optoelectronics

Synthesis of pure and 0.1 to 5?wt.% Gd-doped CdS nanoparticles (NPs) was achieved through a modified domestic microwave-assisted route in a short timespan at 700?W power. The formation of hexagonal CdS NPs was verified via X-ray diffraction analysis, and no structural variation was observed except for lattice variation. The size of the crystallites (D), dislocation concentration, and lattice strain were calculated, and the D was in the range of 3–6?nm. Fourier transform-Raman analysis confirmed the presence of 1LO, 2LO, and 3LO modes at 294.76, 590, and 890?cm^?1, respectively, in all the synthesized nanostructures, with minute variations in their positions due to doping; however, no new mode was observed. The position of the vibration modes was red shifted compared to that of the bulk material, indicating a confinement effect. Scanning electron microscopy (SEM) mapping/energy-dispersive X-ray spectroscopy revealed homogeneous doping of Gd and the presence of all the constituents in the final products. The morphology of the synthesized materials was tested via field-emission SEM, which revealed spherical NPs with small dimensions. Additionally, high-resolution transmission electron microscopy was performed to visualize the shape and size of the prepared 0.1% Gd:CdS NPs. The energy gap was calculated using the Kubelka–Munk theory and found to be in the range of 2.31–2.41?eV. The photoluminescence emission spectra exhibited two green emission peaks at 516?±?2?nm and 555?±?2?nm and showed the reduction of defects with Gd doping in terms of intensity quenching. The dielectric constant (${\epsilon }^{\text{'}}$), loss, and alternating-current electrical properties were studied in the high-frequency range. The values of ${\epsilon }^{\text{'}}$ were in the range of 17–27. An enhancement of these values was observed for CdS when it was doped with Gd. The electrical conductivity exhibited frequency power law behavior.     

Effect of Nd and Nb co-doping on the structural,magnetic and optical properties of multiferroic BiFeO3 nanoparticles prepared by sol-gel method

BiFeO₃, BiFe_0.95Nb_0.05O₃ and Bi_1−xNd_xFe_0.95Nb_0.05O₃ (x=0.0, 0.05, 0.10, 0.15 and 0.20) nanoparticles are successfully synthesized via a tartaric acid-assisted sol-gel technique for the first time. The effect of Nd and Nb co-doping on the structure, morphology, and magnetic and optical properties is investigated. X-ray diffraction (XRD) and Raman measurements demonstrate that Nd³⁺ ions and Nb⁵⁺ ions co-doping at A and B-sites of BiFeO₃ can result in a structural transformation (from single rhombohedral phase (R3c) to two coexisting phases (R3c and Pbam)). The morphology of the nanoparticles seems to be approximately cubic, and by the co-doping, the size of the nanoparticles decreases from ~132 to ~35 nm. Notable improvement in the remanent magnetization of the sample with x=0.15 is observed with a value of 0.285 emu/g, being 20 times higher than that of the undoped sample (BiFeO₃). A decrease in the optical band gap is also observed in the Nd and Nb co-doped nanoparticles, indicating their favorable potential in photocatalytic applications.     

Effect of Ni2+ substitution on structural,magnetic, dielectric and optical properties of mixed spinel CoFe2O4 nanoparticles

Nanoparticles of Co_1−xNi_xFe₂O₄ with x=0.0, 0.10, 0.20, 0.30, 0.40 and 0.50 were synthesized by co-precipitation method. The structural analysis reveals the formation of single phase cubic spinel structure with a narrow size distribution between 13–17 nm. Transmission electron microscope images are in agreement with size of nanoparticles calculated from XRD. The field emission scanning electron microscope images confirmed the presence of nano-sized grains with porous morphology. The X-ray photoelectron spectroscopy analysis confirmed the presence of Fe²⁺ ions with Fe³⁺. Room temperature magnetic measurements showed the strong influence of Ni²⁺ doping on saturation magnetization and coercivity. The saturation magnetization decreases from 91 emu/gm to 44 emu/gm for x=0.0–0.50 samples. Lower magnetic moment of Ni²⁺ (2 µ_B) ions in comparison to that of Co²⁺ (3 µ_B) ions is responsible for this reduction. Similarly, overall coercivity decreased from 1010 Oe to 832 Oe for x=0.0–0.50 samples and depends on crystallite size. Cation distribution has been proposed from XRD analysis and magnetization data. Electron spin resonance spectra suggested the dominancy of superexchange interactions in Co_1−xNi_xFe₂O₄ samples. The optical analysis indicates that Co_1−xNi_xFe₂O₄ is an indirect band gap material and band gap increases with increasing Ni²⁺ concentration. Dispersion behavior with increasing frequency is observed for both dielectric constant and loss tangent. The conduction process predominantly takes place through grain boundary volume. Grain boundary resistance increases with Ni²⁺ ion concentration.     

Comparative structural and optical studies on pellet and powder samples of BaTiO3 near phase transition temperature

In order to investigate the possible effect of inter-granular strain on the physical properties of Barium titanate (BaTiO₃), comparative studies have been carried out on the polycrystalline pellet and its corresponding powder samples. For this purpose, the polycrystalline pellet sample of BaTiO₃ has been prepared via conventional solid-state reaction route and powder is obtained by crushing the part of the prepared BaTiO₃ pellet. The comparative room temperature structural studies, temperature dependent optical and Raman spectroscopy measurements have been carried out on the prepared pellet and powder samples. Room temperature X-ray diffraction and Raman analysis confirms the presence of extra amount of strain in pellet sample compared with that of the powder sample. Temperature dependent Raman analysis also suggests the difference in the high temperature tetragonal to cubic transition temperature in both cases. Temperature dependent optical absorption properties measured in terms of Urbach energy (E_U), Urbach focus (E₀) and Urbach relaxation clearly indicates the significant change in these quantities for both types of samples on BaTiO₃. Present results strongly reveal the difference in structural, optical and vibrational properties of BaTiO₃ especially across phase transition in pellet and its corresponding powder which clearly shows the importance of inter-granular strain at the grain boundaries.     

Dynamic properties of magnetorheological elastomers based on iron sand and natural rubber

In this study, magnetorheological elastomers (MREs) based on iron sand and natural rubber were prepared. The Taguchi method was employed to investigate the effect of a number of factors, namely, the iron sand content, iron sand particle size, and applied magnetic field during curing on the loss tangent (tan δ) and energy dissipated during cyclic loading. Tan δ was measured through dynamic mechanical analysis over a range of frequency (0.01–130 Hz), strain amplitude (0.1–4.5%), and temperature (?100 to 50°C). The energy dissipated was measured with a universal tester under cyclic tensile loading. The data were then statistically analyzed to predict the optimal combination of factors, and finally, experiments were conducted for verification. It was found that the iron sand content had the greatest influence on tan δ when measured over a range of frequency, and the energy dissipated during hysteresis tests. However, none of the factors showed a significant influence on tan δ when measured over a range of strain amplitude. Furthermore, the iron sand content and magnetic field were also found to influence the width of the peak in tan δ as a function of the temperature. The morphological characteristics of the MREs were also examined with scanning electron microscopy. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41506.     

Hydrothermal synthesis of Li co-doped Zn0.98Mg0.02O nanoparticles and their structural,optical and electrical properties

Zn_0.98−xMg_0.02Li_xO (x=0.0, 0.01, 0.02, 0.03) nanoparticles were synthesized by the hydrothermal method. The structural, optical and electrical properties of the samples were analyzed by X-ray diffraction (XRD), Scanning Electron Microscope (SEM), Diffuse Reflectance UV–vis spectroscopy, and Hall effect measurements. XRD results showed that Zn_0.98−xMg_0.02Li_xO with wurtzite structure are obtained without impurities and additional phases. The lattice parameters (a, c) initially decrease, but they increase with further Li doping. The optical measurements exhibited blue-shift of optical band edge and widening of the band gap. Temperature dependent transport measurements using Van der Pauw method showed that Li doping increased the resistivities and charge carrier density, while it decreased the Hall mobility.     

Influence of molybdenum oxide on structural,optical and physical properties of oxychloride glasses for nonlinear optical devices

The unconventional Heavy Metal Oxide Glasses (HMOG) are characterized by a low phonon energy, large infrared range transmission, high refractive index and nonlinear optical properties. Ternary glasses have been synthesized and studied in the Sb₂O₃– MoO₃-ZnCl₂ system. Further, the glass formation compositional limits are reported and some glass samples with the formula: (90-x)Sb₂O₃ -xMoO₃–10 ZnCl₂ (10 ≤ x ≤ 50, mole%) were elaborated. Thermal properties have been measured and indicating that the glass transition temperature decreases with increasing proportions of molybdenum oxide. The evolution of density, microhardness and elastic modulus has been studied as functions of parameter x and Raman spectra measurements have been shown the partial conversion of MoO₆ octahedral units into MoO₄ tetrahedral.     

Effects of aluminium doping on structural and photoluminescence properties of ZnO nanoparticles

Structural and optical properties of Al doped ZnO nanoparticles prepared by the thermal decomposition method are presented. X-ray diffraction studies confirmed the substitution of Al on Zn sites without changing the hexagonal structure of ZnO. Also, lattice parameters, the crystallite size and other physical parameters such as strain, stress and energy density were calculated from various modified forms of W–H equation and their variation with the doping of Al is discussed. A blue shift in the energy band gap attributed to increase in carrier concentration (Burstein Moss Effect) is observed by absorption spectra. Photoluminescence studies show a strong and dominant peak corresponding to the near band edge emission in ultraviolet range and a broad band in the range 420–520 nm corresponding to defects and oxygen vacancies. Phonon modes were studied by FTIR measurements. The tunability of the band gap of ZnO nanoparticles could eventually be useful for potential optoelectronic applications.