Decrease In Gap Research Articles

Investigation of Structural, Dielectric and Optical Properties of Polyaniline-Magnesium Ferrite Composites.

A study on the influence of magnesium ferrite nanoparticles on the optical and dielectric attributes of Polyaniline has been conducted. Magnesium nano Ferrite powder is synthesized by the self-propagating solution combustion method. Polyaniline-Magnesium nano ferrite composites are synthesized by chemical oxidative polymerization of aniline with the addition of Magnesium nanoparticles. The samples are characterized with XRD and UV-Vis spectrometer, in the wavelength range of 200-800 nm and studied for optical properties. Dielectric properties are studied in the frequency range of 50 Hz to 5 MHz. X-ray diffraction reveals single phase formation of Magnesium ferrite, whereas Polyaniline shows an amorphous nature. In the XRD of the composites, we see the crystalline peaks of ferrite becoming more intense with the addition of ferrite and whereas the peak of Polyaniline diminishes. The crystallite size is quantified with the Debye-Scherrer formula, and it increases as the content of ferrite in the composites increases. The micro-strain decreases in the composites as the percentage of ferrite enhances in the composites. In the UV-Vis absorption spectra of composites, the peaks of Polyaniline shift to higher wavelength and there is also an absorption band in the spectra of composites corresponding to that of Magnesium ferrite particles. Both direct and indirect band gaps are calculated with the Tauc plot, and both the optical band gap decrease as the percentage of ferrite increases in the composite. The dielectric loss and dielectric constant both decrease with frequency in all the samples, and the dielectric response are in good agreement with Maxwell-Wagner model. Ferrite-polymer composites with both conducting and magnetic properties are considered useful for electromagnetic shielding and microwave absorption.

From gender equality to household earnings equality: The role of women’s labour market outcomes across OECD countries

We assess the impact that full gender equality in the labour market would have on earnings inequality between households, and then decompose that impact by looking separately at the roles played by gender gaps in employment, hours, and pay. We do this by applying a reweighting method to LIS data for 22 OECD countries, across North America, Europe, and Australia. We find that full equality in earnings and employment between women and men would reduce household earnings inequality considerably, with the most substantial reductions coming from closing the gender gap in employment as opposed to closing the gaps in pay and hours worked. A 10% counterfactual decrease in the gender employment gap (relative to the country baseline) is associated with an average 0.6% decline in the Gini for household earnings inequality. Reducing the gender employment gap is thus the pathway through which greater gender equality may most strongly mitigate overall earnings inequality among households: these two key goals for contemporary societies can be pursued simultaneously.

Influence of nano-hydroxyapatite particles on the mechanical and antibacterial properties of polycarbonate films

In the present research, eco-friendly composite films of polycarbonate (PC)/nano-hydroxyapatite (nHAP) have been successfully prepared using the solution casting method with a concentration of (3, 5, 10 and 15% PS/PC with 1.6 nHAP). These films were characterized to investigate the influence of nano material upon the Ultraviolet (UV)-wethering of the mechanical properties employing tensile test, thermal properties utilizing Lee disk, and antibacterial properties utilizing culture method. From the tests, it was observed that the nano hydroxyapatite led to a reduction in the degradation and an increase in the thermal conductivity. The antibacterial studies manifested that the toxicity was severely decreased via the incorporation of nano hydroxyapatite and became highly antibacterial. Optical constants have been analyzed using UV–vis spectroscopy.Results reveal the decrease in band gap and enhancement in optical constants. FESEM images of 10% PS/PC and 10% PS/PC+1.6 nano particles exhibit a high degree of particle dispersion homogeneity within the 10% PS/PC matrix. The contact angle tests elucidated that the prepared films were highly hydrophobic with a hydrophobocity of 99%, which aids in the antibacterial capabilities and hence they can be used as packaging materials.

Electrical investigation and enhancement of optical, structural, and dielectric properties of flexible PVDF/LiZnVO4 nanocomposites

Thin polymeric films of poly(vinylidene fluoride) (PVDF) containing variable mass fractions of nanoparticles (LiZnVO4) were successfully synthesized via the ordinary solution casting method. X-ray diffraction (XRD), Fourier transform infrared (FT-IR), and ultraviolet–visible spectroscopy were used to explore the role of LiZnVO4 on the structural and optical characteristics of synthesized nanocomposites. In addition, dielectric permittivity (ε' and ε") and dielectric modulus (M' and M") were investigated. The XRD spectral data reveals the crystalline nature of pure LiZnVO4 with rhombohedral structure with an average size of 83 nm calculated using the Scherrer’s equation and W-L plot. The interaction between PVDF and LiZnVO4 was approved through the shift in characteristics in some IR bands. The decrease in band gap energies with increasing LiZnVO4 was attributed to the change of density in the localized states within the PVDF matrix. The effect of both frequency and temperature on the AC parameters was also investigated. Both ε' and ε" had their maximum values at low frequencies and decreased as the frequency and temperature increased. The results from XRD and FT-IR were correlated with changes in the dielectric characteristics at the maximum level value of LiZnVO4, suggesting the potential of these materials as basic components for lithium-ion batteries.

Outcomes and Prognostic Factors of Balloon Eustachian Tuboplasty Combined With Ventilation Tubes Insertion in Children: A Retrospective Study.

Objective: To evaluate the efficacy and safety of balloon eustachian tuboplasty (BET) combined with ventilation tube (VT) insertion in pediatric population and to identify the predictive factors for symptom recurrence. Methods: We conducted a retrospective study between August 2018 and February 2022 at Shenzhen Children's Hospital. The study analyzed the data of pediatric patients who underwent BET + VT insertion, as well as the data of pediatric patients who underwent VT insertion alone. The outcomes were efficacy, safety, and predictive factors of BET combined with VT. Kaplan‒Meier curves were used to examine the failure-free survival rate. A multivariate Cox regression model was used to identify the independent predictors of BET failure. Results: We evaluated the data of 29 pediatric patients (48 ears) who underwent BET with VT insertion (BET + VT group) and the data of 29 pediatric patients (46 ears) who underwent VT insertion alone (VT group). The total effectiveness rates at the first follow-up after VT removal and at 12 months in the BET + VT group were 90.9% and 84.6%, respectively. The decrease in the air-bone gap (ABG) was more significant in the BET + VT group at 12 months (13.7 ± 10.8 vs 6.4 ± 15.3, P < .05). The subgroup analyses did not show any significant difference between the groups in high-risk. For non-high-risk patients, the decrease in the ABG was more significant in the BET + VT group (14.2 ± 10.6 vs 4.3 ± 13.1, P < .05) at 12 months. The multivariate analysis showed that a history of VT insertion was independently associated with a higher rate of recurrence in the BET + VT group (hazard ratio 3.177; 95% CI, 1.027-9.826; P < .05). Conclusions: BET + VT insertion is an effective procedure to decrease the ABG in pediatric patients with eustachian tube dysfunction (ETD) who have no risk factors for conventional therapy failure. Treatment of patients with ETDs who have coexisting risk factors remains a challenge that warrants further high-quality prospective research.

Composite of graphitic carbon nitride and TiO2 as photo-electro-catalyst in microbial fuel cell.

The widespread application of surfactants and their subsequent discharge in the receiving water bodies is a very common issue in developing countries. In the present investigation, a composite of graphitic carbon nitride (GCN) and TiO2 was used as a photo-electro-catalyst in a microbial fuel cell (MFC)-based hybrid system for bio-electricity production and simultaneous pollutant removal (organic matter and sodium dodecyl sulphate, SDS). The GCN: TiO2 composite with a ratio of 70:30 (by wt. %) revealed a better electrochemical response; thus, it was used as a photo-electro-catalyst in MFC. Additionally, the photochemical characterization indicated a decrease in the band gap and charge recombination of GCN-TiO2 composite compared to standalone TiO2, which indicated a conducive effect of GCN addition. Further, on the actual use as a photo-electro-catalyst, the GCN-TiO2 catalysed MFC attained 58.2 ± 9.6% and 86.5 ± 7.1% of COD and SDS removal; while simultaneously harvesting a maximum power density of 1.07 W m-3, which was higher than standalone TiO2-catalysed MFC. The follow-up treatment in the charcoal bio-filter and photo-cathodic chamber of the hybrid system further improved the overall COD and SDS removal efficiency to 92.1 ± 2.7 and 95.6 ± 1.5%, respectively. The electro-catalytic performance of the GCN-TiO2 can be attributed to the presence of nitrogen-active species in the composite. The results of this investigation demonstrated a potential MFC-based hybrid system for the simultaneous secondary and tertiary treatment of municipal wastewater. Consequently, the outcome of this investigation indicates an innovative research direction in the field of photo-electro-catalyst, which can fit into the role of a photo-catalyst as well as an electro-catalyst.

Effect of calcination temperature on phase composition and optical properties of Al-ZnO nanocrystalline films

Nanocrystalline Al-ZnO films were successfully synthesized by thermal decomposition method. The method includes two stages: synthesis from the melt of organic salts and the films production. The effect of the calcination temperature varying from 600 to 800 °C on the crystallite sizes, phase composition and optical properties of the synthesized films was also investigated. X-ray diffraction (XRD) showed the formation of a hexagonal wurtzite crystal structure with a distorted lattice upon the introduction of Al3+ ions. Based on calculations and scanning electron microscopy (SEM) images, the crystallites size increased from 18 to 28 nm with the calcination temperature increasing. Optical properties of Al-ZnO films were studied by optical transmission spectra. An increase in the calcination temperature leads to a decrease in the ZnO band gap. It was shown that the proposed method makes it possible to obtain optically transparent Al-ZnO films consisting of nanocrystallites. By varying the calcination temperature, the optical properties can be adjusted, which will significantly expand the application range of these materials.

The Influence of Halide Ion Substitution on Energy Structure and Luminescence Efficiency in CeBr2I and CeBrI2 Crystals.

This study aims to determine the optimum composition of the CeBr1-xIx compound to achieve the maximum light output. It is based on calculations of the band energy structure of crystals, specifically taking into account the characteristics of the mutual location of local and band 5d states of the Ce3+ ions. The band energy structures for CeBr2I and CeBrI2 crystals were calculated using the projector augmented wave method. The valence band was found to be formed by the hybridized states of 4p Br and 5p I. The 4f states of Ce3+ are located in the energy forbidden band gap. The conduction band is formed by the localized 5d1 states, which are created by the interaction between the 5d states of Ce3+ and the 4f0 hole of the cerium ion. The higher-lying delocalized 5d2 states of Ce3+ correspond to the energy levels of the 5d states of Ce3+ in the field of the halide Cl0 (Br0) hole. The relative location of 5d1 and 5d2 bands determines the intensity of 5d-4f luminescence. The bottom of the conduction band is formed by localized 5d1 states in the CeBr2I crystal. The local character of the bottom of the conduction band in the CeBr2I crystal favors the formation of self-trapped Frenkel excitons. Transitions between the 5d1 and 4f states are responsible for 5d-4f exciton luminescence. In the CeBrI2 crystal, the conduction band is formed by mixing the localized 5d1 and delocalized 5d2 states, which leads to quenching the 5d-4f luminescence and a decrease in the light output despite the decrease in the forbidden band gap. CsBr2I is the optimum composition of the system to achieve the maximum light output.

SYNTHESIS OF Pd NPs VIA LASER ABLATION IN LIQUID ASSISTED WITH MAGNETIC FIELD ON SILICON NANOSTRUCTURE FOR GAS SENSOR

In this work, palladium nanoparticles (Pd NPs) are synthesized by laser ablation in liquid (PLAL) with wavelength 532[Formula: see text]nm (second harmonic Nd:YAG laser) at different laser energies 360, 660, and 800[Formula: see text]mJ with 200 pulses and an electric coil is used to generate a magnetic field. The resulting nanosolution was deposited on the previously prepared PS. The morphological and structural properties of the prepared substrates (Pd NPs/PS) are calculated by X-ray diffraction (XRD) pattern, Atomic Force Microscope (AFM), and Transmission Electron Microscopy (TEM). Their results showed that with the increase in the energy of laser pulse, the average particle size was 30.73, 22.60, and 18.01[Formula: see text]nm. Optical properties of Photoluminescence (PL) spectra show decrease of energy band gap at 2.38, 2.43, and 2.47[Formula: see text]eV with an increase in the energy. The sensitivity of application samples Pd NPs/PS/Si gas sensors for NO2 and H2S gas was also investigated with respect to temperature variations. Pd NPs/PS/Si gas sensors have a maximum sensitivity of NO2 gas around 52.6% at [Formula: see text]C for sample prepared at energy 360[Formula: see text]mJ but the highest sensitivity of H2S gas was 31.2% at [Formula: see text]C for energy of 660[Formula: see text]mJ. The effects of the operating temperature on reaction and recovery durations for various laser ablation energies are also discussed.

Optical characterization of PVDF/PMMA/OMMT hybrid polymer nanocomposite films for futuristic optoelectronic devices

Hybrid polymer nanocomposite (HPNC) films based on poly(vinylidene fluoride) (PVDF)/poly(methyl methacrylate) (PMMA) blend (80/20 wt/wt%) host matrix and organo-modified montmorillonite (OMMT) nanoclay filler (concentrations 0.0, 2.5, 5.0, and 10 wt%) are prepared by the homogenized solution casting method. The X-ray diffraction (XRD) and scanning electron microscopic (SEM) studies revealed the formation of intercalated and exfoliated OMMT structures in the prepared composites. The detailed optical characterization of these HPNC films is carried out with measurements of absorbance spectra by employing a dual beam ultraviolet-visible (UV-Vis) spectrophotometer of wavelength range 200–800 nm. The varying amounts of dispersed OMMT into the PVDF/PMMA blend matrix leads to a gradual decrease in the direct energy band gap of the host matrix from 5.12 eV to 4.54 eV and also shows semiconductive characteristics of 3.83 eV wide band gap at higher nanofiller concentrations. The band gap values of these HPNC films are compared and discussed with other composites of different polymer blend matrices dispersed with a variety of nanofillers. The increase of OMMT concentrations enhanced the range of refractive index (1.85–2.65), extinction coefficient (1.14–10.69 × 10–4), optical range dielectric permittivity (3.44–7.07), and optical conductivity (1.32–17.14 × 1011 s−1) of these HPNC films, at a fixed wavelength of 500 nm, which further changes largely with the alteration in wavelength of incident photons. The nanofiller concentration controllable optical parameters of these PVDF/PMMA/OMMT based HPNCs reveal that they could be promising performance and multipurpose optical materials in the advances of futuristic flexible-type optoelectronic devices.

Effects of Fe and Ni Doping on the Electronic Structure and Optical Properties of Cu2ZnSnS4

This study evaluated the electronic structure and optical properties of Fe-doped, Ni-doped, and (Fe,Ni)-co-doped Cu2ZnSnS4 through the first-principles pseudopotential plane-wave method based on density functional theory. The results indicated that Fe single-doping and Ni single-doping Cu2ZnSnS4 can reduce the charge transfer number of adjacent S atoms, enhancing covalent bonding in Fe–S and Ni–S bonds and reducing the bond length, lattice constants a and c, and unit cell volume v. The formation energies for Fe-doping, Ni-doping, and (Fe,Ni)-co-doping were 1.0 eV, 0.58 eV, and 0.78 eV, respectively. Both Fe and Ni-doping introduced 3d electrons near the Fermi level, resulting in new impurity levels and a gradual decrease in the band gap of Cu2ZnSnS4 from 0.16 eV. The conduction band density of Cu2ZnSnS4 was primarilycontributed by Sn 5s, Sn 5p, and a portion of S 3p orbital electrons, whereas the valence band density mainly stemmed from Cu 3d, Sn 5p, and S 3p orbital electrons. Fe and Ni-doping also partly contributed to the 3d layer electrons. In the case of (Fe,Ni)-co-doping, the maximum static dielectric constant was 100.49, and the dielectric peak shifted toward the low-energy direction in the presence of both Fe and Ni. Within the visible light range, Fe-doping, Ni-doping, and (Fe,Ni)-co-doping in Cu2ZnSnS4 exhibited absorption coefficients greater than 104 cm−1, with the maximum absorption coefficient being 1.6 × 105 cm−1 in the case of (Fe,Ni)-co-doping. In the energy range from 1.5 to 6.3 eV, the reflectivity of Cu2ZnSnS4 doped with Fe, Ni, or both was lower than 30%. Notably, a high conductivity peak at 1.9 eV indicated that Cu2ZnSnS4 possesses good photoconductivity in the visible range. Fe-doping and Ni-doping resulted in a slight shift of the conductance peak position towardthe low-energy direction, accompanied by an increase in the peak value.

A Successful Study of the Government's Poverty Alleviation Approach to the Coastal Poor for Education Aspect in Bau-Bau City, Southeast Sulawesi

Poverty is more common in rural areas than in urban areas. Even though there has been a decrease in poverty, this has not been followed by a decrease in disparities or gaps between cities and rural areas. So,the government's poverty alleviation approach tends to be the same (G2P) between urban and rural areas. This should have an even impact on reducing poverty and regional disparities especially fo education aspect. bymixed research (mixed method) between qualitative and quantitative research, the reseach tried to answer How successful is the distribution of assistance to the poor in coastal cities in the education sector in Baubau City, Southeast Sulawesi Province?. The data showed that the distribution of social assistance for the G2P scheme to urban coastal poor households in Baubau City for the education sector was categorized as "successful or on target", but had not reached the "very successful or very targeted" category as expected by TNP2K. This result also answers the first hypothesis that the distribution of assistance to poor households in urban coastal areas is "successful". In accordance with the results of the analysis (strengths and weaknesses) and referring to the benefits to be achieved, there are several suggestions put forward practically and conceptually/theoretically. distribution of aid by taking into account the results of this study (advantages and disadvantages of the distribution process) so that in the future the distribution process will be even better.

Diagonal and Vertical B ← N Lewis Pair Functionalized Perylenes.

Two novel multiple B ← N Lewis pair functionalized perylenes are reported. While OBN-Pery shows a centrosymmetric and planar architecture, PBN-Pery displays an axisymmetric and twist structure. B ← N functionalization in both of them results in a large decrease in the HOMO-LUMO energy gap. PBN-Pery in particular has a low LUMO energy level (-3.00 eV) and red emission at the NIR I region with high fluorescence quantum yield.

Ab initio investigations of crystal transition for graphite intercalation compounds during aluminum electrolysiss

This paper studies the crystal transition of graphite intercalation compounds during aluminum electrolysis. Transmission electron microscopy (TEM) analysis demonstrates that the transition induces the structural degradation of carbon cathodes. Buckling of basal planes in the hexagonal compounds contributes to the crystal transition of intercalation compounds from hexagonal to rhombohedral modification. First-principle techniques are used to calculate the structural and electronic properties of graphite intercalation compounds by density-functional theory using the plane wave Pseudo-potential method. The results have demonstrated a close relationship between lattice mismatch and intercalation compounds. The electronic band structure close to the Fermi level has been investigated. The main effect of intercalation compounds is to transfer charge from alkali metal s electron to the carbon pz orbitals, rendering the system metallic. With a decrease of band gap, the crystal transition induces an increase in the interlayer spacing and C–C bond lengths and deteriorates the structural stability of carbon cathodes. The overwhelming majority of contribution to the bands neighboring the Fermi level is from C pz orbital in both intercalation compounds. These findings provide new insights into the mechanisms of carbon cathodes deformation, damage and fracture behavior.

Quinone functionalized highly porous polymer as cathode material for Mg ion batteries: A DFT study

Magnesium ion batteries (MIBs) are one of the vital strategies for the next-generation energy needs and computational simulations can accelerate this search many folds. In this paper, we suggest a novel cathode material, quinone functionalized hexahydroxytriphenylene (HHTP) and diphenylbutadiynebis (boronic acid) (DPB) based porous polymer (QHHTP-DPB), for Mg-ion batteries. The material is stable with highly porous structure and strong affinities for Mg ions to attach to C=O sites of the quinone rings. The single unit of the polymer layer can be fully loaded with Mg ions at various active sites exhibiting a specific theoretical-capacity of 720.48 mAhg−1 and positive low open-circuit voltage of 0.39 V. No structural variation is observed in QHHTP-DPB and a larger decrease in the HOMO-LUMO gap occurs after Mg ions adsorption onto the polymer, reflecting the better cycling performance and high capacity for Mg ion batteries. These results show that our designed quinone functionalized HHTP-DPB porous polymer could be a futuristic cathode material for MIBs and needs further theoretical and experimental investigations.

Photoluminescence and third-order nonlinear optical limiting properties of Sn1-xNdxO2 thin films deposited via spray pyrolysis

In the present work, spray pyrolysis method was adopted to synthesis nano thin films of Sn1-xNdxO2 (x = 0.01 to 0.1) possessing tetragonal structure with (1 1 0) plane orientation. Nd doping reduced the overall crystallinity of the films, however Sn0.92Nd0.08O2 film showed crystallite size of 18.7 nm, similar to that of the pure film. The morphology changed to distinct grains at lower doping concentration, beyond which a fibrous nature evolved but again changed to smaller grains with further increase in the doping. The oxidation states of the constituent elements were confirmed using XPS. The transmittance of the films reduced due to incorporation of Nd ions. A decrease in the energy band gap was also noticed in the films following dopant addition. The PL emissions corresponding to the Nd ion transitions was found in the NIR region resulting from internal 4f-shell transitions of Nd3+ ions. Other defect related emissions like the one from oxygen vacancies also showed up in the UV and visible wavelength regions, which were responsible for a near white light emission. The third-order optical nonlinearity of the films was confirmed using the Z-scan technique. All the Sn1-xNdxO2 films till 8 at. % of doping showed reverse saturable absorption. The highest and lowest nonlinear absorption coefficient was exhibited by Sn0.92Nd0.08O2 and Sn0.98Nd0.02O2 films, respectively. Depending on the Nd concentration, the films either showed self-focusing or self-defocusing behavior and influenced the nonlinear refractive indices of the films. The least optical limiting values among the doped films was obtained in the range of 1.73 kJ/cm2 for Sn0.92Nd0.08O2 films.

Effect of post-weld heat treatment on the microstructure and properties of titanium/304 stainless steel laser welding dissimilar metal joints with copper as the transition layer

Low elongation has been an important factor limiting the application of titanium/304 stainless steel (304SS) laser welding of dissimilar metal joint products. By adopting the post-weld heat treatment (PWHT) process of holding the welded joint at 400 ℃, 550 ℃ and 700 ℃ for 30 min, this study increases the elongation of the welded joint from 0.3 % to 2.21 % in the welded state and further analyses and investigates the structural changes in the organization and the formation process of intermetallic compounds (IMC) within the weld seam. The results showed that the acicular structure in the weld could not be eliminated by holding at 400 ℃ for 30 min, but only part of the residual stress was released, and the elongation was increased to 0.85 %. After holding at 550 ℃ for 30 min, a large number of equiaxed crystals appeared to replace the acicular structure in the weld and released the residual stress. With the enhancement of the IMC layer thickness, grain gap and deformation coordination ability, the elongation increased to 2.21 %. After holding at 700 ℃ for half an hour, the IMC layer becomes thinner, the grain gap decreases, the deformation coordination ability deteriorates, and the tensile strength and elongation decrease. In the tensile test, the fracture position was all at the weld. After being held at 400 ℃ for 30 min, the average tensile strength of the tensile sample increased from 330 MPa in the welded state to 352 MPa; after being held at 550 ℃ for 30 min, the average tensile strength of the tensile sample was 340 MPa, and the fracture elongation was 7.4 times that of the welded state, reaching 331 µm.

Exploring the effects of ultra-low loading level of silver oxide nanoparticles on the dielectric, I-V characteristics and optical energy band gap of thermoplastic polyurethane and poly-aniline blend nanocomposites

This study deals with the exploration of ultra-low loading levels of Silver oxide (Ag2O) nanoparticles on the materials properties such as dielectric, I-V characteristics, and optical energy band gap of thermoplastic polyurethane (TPU) and Polyaniline (PANI) blend nanocomposites. The nanocomposites with varying loading levels of Ag2O nanoparticles have been fabricated using the most simplified solvent casting technique. The dispersion pattern of the Ag2O phase in the vicinity of the TPU and PANI Matric has been observed from the high-resolution transmission electron microscopic (HRTEM) analysis. The dielectric properties like dielectric permittivity(εʹ), AC conductivity (σac), Nyquist plot, etc., of the fabricated nanocomposites have been explored in a wide range of frequency of the applied electric field (1 -106Hz). The significant improvement in εʹ with a 3 wt% loading level of Ag2O is one of the outstanding findings of today’s research work. The obtained I-V characteristics indicate the formation of dielectric materials with pseudo-metallic behavior. The decrease in optical energy band gap with the addition of Ag2O ensures the suitability of the fabricated nanocomposites to be used in the construction of the solar cell. Dielectric properties ensure the suitability of the materials to be used in the construction of the buffer layer of solar cells and the fabrication of EMI shielding panels to be used in heavy electronics where radiation leakage is very frequent.

Synthesis and dielectric behaviour of La and Cr modified NaNbO3 (x ≤ 0.06)

Compositions with x = 0 and x = 0.06 in the material system Na1-xLaxNb1-xCrxO3 are prepared by conventional solid-state reaction method. XRD results show that all the prepared samples exist in single phase having orthorhombic structure with Pbcm space group symmetry. UV results show a decrease in band gap with x = 0.06. FTIR results show the shifts of bands towards higher wavenumber side for x = 0.06. Dielectric plots from room temperature to 773 K show two anomalies one at 404 K and other at 610 K for pure NaNbO3. For La and Cr doped sample with x = 0.06, the anomaly appearing at 404 K for pure sample is suppressed and a new anomaly starts appearing at 490 K. Also, the anomaly appearing at 610 K in NaNbO3 has disappeared and the signature of anomaly at 695 K is seen in modified NaNbO3 with x = 0.06.

Multifunctional properties of transition metal based double perovskite ceramics

In this manuscript, iron based double perovskite oxides Ca2Fe1-xNixNbO6(x=0, 0.1) were successfully synthesized adopting the physical mixed oxide route and high temperature annealing. The influence of Ni substitution on the structure, band gap tuning, leakage current, dielectric, energy storage and magnetic properties of the parent ceramic is also discussed. A relatively high remnant polarization of 11.8 µC/cm2 with a reduced band gap of 1.9 eV is noticed in the Ni modified ceramic. It is found that the saturation magnetization increases from 0.359 emug−1 to 0. 892 emug−1 whereas the leakage current density decreases from 6.869E−6 to 5.52E-6 A/mm2 upon Ni substitution. The enhanced saturation magnetization and ferroelectric properties of the modified ceramic with lesser leakage current increases their energy storage capacity. The energy storage efficiency of the Ni substituted material increases from 15.52% to 71% with a reduction of hysteresis loss. Hence the increase in remnant polarization and decrease in band gap of the Ni modified ceramic aligns it toward ferroelectric photovoltaic application.