Crystallite Size Research Articles

Circularly Polarized Luminescence from Pure and Eu-Doped Trigonal TbPO4·nH2O Nanocrystals.

In this contribution, we describe the preparation, by means of a precipitation reaction from aqueous solution at 40 °C, and the structural characterization of nanocrystalline powders of trigonal Tb1-xEuxPO4·nH2O (with x = 0, 0.005, 0.01, 0.05, and 0.1; n tentatively assigned as 0.67) which crystallize in the two possible P3121 or P3221 enantiomorphic space groups. While the volume of the crystal lattice is not significantly affected by the Tb3+/Eu3+ substitution, the average crystallite size seems to depend on the Eu3+ dopant concentration and ranges from 13 to 30 nm. The desired handedness of the crystals has been induced by using, during the synthesis, one of the two possible enantiomers of tartaric acid (l or d). The analysis of the luminescence excitation and emission spectra, together with the decay kinetics of the 5D4 Tb3+ excited state, suggests the presence of a very efficient Tb3+ → Eu3+ energy transfer process in the Eu3+-doped orthophosphates. Upon excitation of Tb3+ ions at 368 nm, the enantiomorphic powders grown with l- or d-tartaric acid (i.e., l-TbPO4·0.67H2O/d-TbPO4·0.67H2O, l-Tb0.995Eu0.005PO4·0.67H2O/d-Tb0.995Eu0.005PO4·0.67H2O, and l-Tb0.9Eu0.1PO4·0.67H2O/d-Tb0.9Eu0.1PO4·0.67H2O) exhibited mirror circularly polarized luminescence signals in the visible spectral region (in the green and/or in the red).

High Performance Flexible Supercapacitor Based on Single Precursor Derived NiFe2O4 Spinel with Tailored Cationic Distribution and Oxygen Vacancies in Acidic Medium

AbstractSpinel metal oxides are extensively studied for supercapacitors (SCs) in alkaline electrolytes, where charge storage capacity is limited by surface site availability due to surface reconstruction forming metal hydroxides/oxyhydroxides. The use of an acidic medium, which can boost the charge storage capacity of spinel oxides offering an additional channel of intercalation‐deintercalation of protons, is underexplored. Moreover, the impact of chemical compositions and the cationic distributions is crucial on the electrocatalysis performance of spinel oxides, however, such a correlation is first time reported for charge storage properties of spinel ferrite NiFe2O4 nanoparticles (NFO NPs). Besides, a low‐cost and scalable synthesis of NFO NPs involving the thermal decomposition of Ni‐Fe glycolate, followed by controlled air‐calcination is reported. Thus crafted NFO NPs‐based device shows impressive specific capacitance (2112 F g−1 at 10 A g−1) in half‐cell configuration. A flexible all‐solid‐state asymmetric device (full‐cell) configuration depicts impressive energy density (20.7 Wh kg−1), power density (4000 W kg−1), gravimetric capacitance (140 F g−1 at 2 A g−1), and retention of its performance (≈75% after 10,000 charging/discharging cycles). The results depict a new insight toward the tuning of electronic and charge storage properties in NFO, which otherwise are predominately attributed to only the crystallite size and morphological effects.

Effect of annealing duration on the structural, optical and magnetic properties of NiO/NiFe2O4 nanocomposites

The impact of annealing time on the structural, optical, and magnetic characteristics of NiO/NiFe2O4 nanocomposites (NCs) was examined after successful synthesis via a straightforward economical wet chemical method. X-ray diffraction (XRD) characterization reveals the presence of cubic NiO as the predominant phase along with the minor phase fraction of NiFe2O4. Slight growth in the crystallite size from 38.96 to 40.25 nm is noticed with the rise of annealing duration. The suppression of intensity of the 2M Raman mode of NiO matrix confirms the decreasing trend of antiferromagnetic (AFM) correlations with the elevation of annealing time. The band gap of the samples increased from 3.38 to 3.98 eV upon increasing the annealing duration. The samples showed strong emissions in the UV region along with other visible emissions. The CIE chromatographic image of the samples indicated the shift of colour emission from blue to the near green region with increasing annealing time. Magnetization data suggests the presence of weak ferromagnetic feature in the background of the AFM NiO matrix at 300 K. The remanent magnetization of the samples increased slightly from ∼0.23 to 0.27 emu g−1 with increasing annealing duration along with perseverance of exchange bias (EB) in all samples at room temperature.

Morphological Characterization of Sb-Doped SnO2 Thin Films Developed by Spray Pyrolysis

In the present work, we have successfully deposited Sb antimony doped tin dioxide (SnO2) thin films with different concentrations (0 at%, 1 at%, 3 at% and 5 at%) from a stannous (II) chloride dihydrate solution (SnCl2.2H2O), by the pyrolysis chemical spray deposition technique on ordinary microscope glass substrates preheated to a fixed temperature of 350 °C. After deposition, the films were annealed at temperatures 400 °C for 4h. The aim of this work is on the one hand to study the morphological properties of pure and doped tin dioxide thin films and to determine the different morphological parameters such as: the roughness Ra, Rq and on the other hand to study the effect of Sb doping on the morphological properties of SnO2 thin films. To achieve this purpose, the thickness of all the films was estimated by profilometer with standard scan type. The morphology of the films was examined by atomic force microscope (AFM) in contact mode at room temperature to visualize the surface of our samples (the structure, size and morphology of crystallites ... etc). The 2D and 3D AFM images confirm the formation of nanostructures on the surface, with shapes and dimensions influenced by the amount of antimony doping. All the samples show a polycrystalline morphology, and the grain size progressively decreases with the increase of the Sb concentration (1% and 3%). On the other hand, for high antimony doping (5% Sb) the grains are larger than those observed at 3% doping. The root mean square (RMS) surface roughness values for samples with Sb concentrations (5%) were found to be 8.334 nm.

Physical properties of InxSey and CuInSe2 thin films with potential application in radiation detectors

Abstract A study of InxSey and CuInSe2 thin films processed by the thermal co-evaporation technique by evaluating its physical properties is carried out. Both InxSey as well as CuInSe2 thin films were synthesized by multi-source thermal co-evaporation technique, using Knudsen-type effusion cells. The optical, structural, electrical, and morphological properties of each film were analyzed in order to determine the feasibility at the formation of a p-CuInSe2/n-InxSey heterojunction. InxSey films exhibited bandgap values in the range of 2.4 - 2.7 eV which was determined by UV-Vis spectroscopic analysis. Vibrational modes associated to In2Se3 as well as Se are presented in the InxSey films according to Raman studies. The irregular morphology of the grains on the InxSey surface, with an average size of 380 nm are related to both In2Se3 and Se materials according to Raman spectroscopy and Scanning Electron Microscopy analysis. The InxSey thin films showed resistivity vales around 10-3 Ω∙cm. The Hackee´s Figure of Merit (FOMH) analysis supported the physical assumption that InxSey thin films are feasible to be used as window layer in a photovoltaic device because of the high values of FOMH obtained for samples processed at 300 °C. On the other hand, an influence on the morphology of the CuInSe2 films was observed when the films were synthetized at different substrate temperature. Uniform CuInSe2 films with agglomerated cauliflower-like grains with an average size of 1.8 μm were observed by SEM. The presence of binary phases within the CuInSe2 compound were detected through Raman and X-Ray characterization. Average crystallite size of 61 nm and microstrain around 2.5 x10-3 were estimated for the CuInSe2 films through X-Ray analysis. According to the physical properties analyzed the InxSey/CuInSe2 semiconductor bilayer can be a suitable candidate for application in photovoltaic devices as well as charged particle detector.

A comparative study of the Au/n-Si (MS) and Au/(ZnO:CeO2:PVP)/n-Si (MPS) Schottky structures by using current/voltage characteristics in dark and under illumination

Abstract In the present study, both MS and MPS SDs were grown onto same n-Si wafer to compare their electrical and optical characteristics. Firstly, ZnO and CeO2 nanostructures were synthesized by ultrasonic-assisted method (UAM), and structurally characterized by utilizing XRD, Ultraviolet-visible spectroscopy (UV-Vis), and Fourier-Transform-IR (FTIR) methods. The mean submicron crystallite sizes were estimated to be below 11.39nm for CeO2 and 54.37nm for ZnO nanostructures through the Debye-Scherrer method. The optical-bandgap was calculated as 3.84eV for CeO2 and 3.88eV for ZnO nanostructures via Tauc plot. Electrical parameters such as reverse-saturation current (Io), ideality-factor (n), zero-bias BH (ΦBo), and rectification-ratio RR were found as 0.596μA, 5.45, 0.64eV, 2.74x105 in dark and 5.54μA, 5.88, 0.59eV, 8.60x103 under illumination for the MS SD and 0.027μA, 4.36, 0.72eV, 1.85x107 in dark and 0.714μA, 5.18, 0.64eV, 7.61x104 under illumination for the MPS SD, respectively. The energy-dependent profile of surface-states was obtained via the Card-Rhoderick method, by considering ΦB(V) and n. RR of the MPS SD is almost sixty-seven times the RR of the MS SD in dark. Sensitivity of the MPS SD (=710) is nineteen and five tenths the sensitivity of the MS SD (=36.4), so the MPS SD is considerably more sensitive to illumination. These results indicate that the (ZnO:CeO2:PVP) organic-interlayer significantly improves the performance of the MS SD.

Exploring novel double perovskite SrEuTiFeO6: Synthesis, microstructural, optical, and dielectric properties

AbstractThe novel double perovskite oxide SrEuTiFeO6 was synthesized using the solid‐state reaction method. X‐ray diffraction analysis, complemented by Rietveld refinement, confirmed that this material crystallizes in a cubic double perovskite structure with the Pm3̅m space group and revealed cationic disorder at both the A (Sr, Eu) and B (Ti, Fe) sites. Crystallite size and lattice strain were determined through various methods. Fourier‐transform infrared spectroscopy was utilized to examine vibrational modes and bond distortions within this material. Scanning electron microscopy showed a heterogeneous microstructure, with a wide distribution of grain sizes and shapes, resulting from the kinetics of the solid‐state synthesis. Energy dispersive X‐ray spectroscopy confirmed the material's homogeneity, stoichiometry, and chemical composition. UV–visible spectroscopy was used to investigate the optical properties of SrEuTiFeO6, identifying several characteristic optical transitions. The band gap energy and refractive index were found to be 2.08 eV and 2.60, respectively, indicating the material's potential for various applications. Additionally, the dielectric properties, including the relative dielectric constant and loss tangent, were thoroughly analyzed as functions of frequency and temperature. The electrical conductivity dispersion phenomenon was also analyzed according to Jonscher's power law, revealing the predominance of overlapping the large polaron tunneling mechanism.

Sodium titanate nanostructured modified by green synthesis of iron oxide for highly efficient photodegradation of dye contaminants

Abstract In this study, sodium titanate (ST)/iron oxide (Fe2O3) was successfully prepared as a novel binary photocatalyst for the first time to enhance the photocatalytic activity. The prepared photocatalyst was used in the photodegradation of methylene blue (MB) dye under sunlight and a tungsten lamp. The green synthesis method using orange peel extract was employed to prepare Fe2O3, while the hydrothermal method was used to synthesize ST. To achieve optimal photocatalytic efficiency, the loading of Fe2O3 onto ST was carefully controlled. The average crystallite size of ST, Fe2O3, and ST@Fe2O3 (with a 1:1 wt% ratio) was 999.8, 81.9, and 104 nm, respectively, using the Williamson–Hall (W–H) model. Optical analysis revealed that ST@Fe2O3 had a smaller direct bandgap (2.54 eV) compared to ST@0.3 Fe2O3 (2.70 eV) and ST@0.5 Fe2O3 (3.24 eV). The photodegradation of MB was analyzed considering the weight of the photocatalyst, the irradiation time, and the dye concentration. In-depth explanations of stability and kinetic models were also provided. Remarkably, the ST@Fe2O3 photocatalyst demonstrated superior performance compared to the other evaluated photocatalysts, completely degrading MB dye within just 60 min of solar light exposure. Incorporating Fe2O3 into ST effectively reduces the recombination of photo-produced electron/hole (e/h) pairs and broadens the response range of the solar spectrum. Based on these findings, ST@Fe2O3 appears to have a promising future as a practical photocatalyst for degrading various dye pollutants in wastewater.

Synergistic Influence of Doping and Co‐Doping of Trivalent Ions (La+3 and Al+3) on YFeO3 Nanomaterials

Herein, the structural, optical, and magnetic properties of Y0.85La0.15FexAlyO3: (x; y) where x = 1; y = 0, x = 0.975; y = 0.025, x = 0.95; y = 0.05, and x = 0.9; y = 0.1 nanomaterials obtained from sol–gel method are reported. The X‐ray powder diffraction (XRD) for the structural characterization, scanning electron microscopy for crystallite size estimation, ultraviolet–visible absorption for optical studies, and vibrating‐sample magnetometer for magnetic studies are used in this investigation. An increase of orthorhombic crystal structure with an increase of Al content in the sample is observed from XRD studies. The existence of all the elements present in the samples is observed from energy‐dispersive X‐ray spectroscopy. The optical bandgap increases from 2.04 to 2.10 eV with an increase of Al concentration from 0 to 0.05. The observed magnetization value is 3.14 emu g−1 for y = 0.05, which is higher than y = 0 (2.11 emu g−1) and y = 0.024 (2.58 emu g−1). In summary, the obtained result (x = 0.95; y = 0.05) can be useful for different magnetic‐based applications.

Effect of TiO2 on Acidity and Dispersion of H3PW12O40 in Bifunctional Cu-ZnO(Al)-H3PW12O40/TiO2 Catalysts for Direct Dimethyl Ether Synthesis

The performance of bifunctional hybrid catalysts based on phosphotungstic acid (H3PW12O40, HPW) supported on TiO2 combined with a Cu-ZnO(Al) catalyst in the direct synthesis of dimethyl ether (DME) from syngas has been investigated. In this work, different types of TiO2 were used as a support to study the effect of changes in the structure of the TiO2 support on the acidity and dispersion of HPW. Various TiO2 supports with different structural and surface characteristics have been studied and the results indicate that: (i) the crystallinity and crystallite size of the primary particles of the HPW units depend on the TiO2 support; (ii) the pore size distribution of the TiO2 support affects the surface segregation of the heteropolyacids; and (iii) changes in the supported HPW acid catalysts do not significantly alter the crystal structure of the CuO and ZnO phases after contact with CZA in bifunctional catalysts. The activity results indicate that the variation in the intrinsic activity of the Cu-ZnOx centers in the bifunctional catalysts for direct DME synthesis is minimal due to the limited alteration of the crystal structure of the centers.

Eco-Friendly Synthesis of Al2O3 Nanoparticles: Comprehensive Characterization Properties, Mechanics, and Photocatalytic Dye Adsorption Study

Metal and metal oxide nanoparticles are gaining traction in inorganic catalysis and photocatalysis, driving the development of eco-friendly methods. This study introduces an eco-friendly and cost-effective approach for synthesizing Al2O3 nanoparticles (NPs) using extracts derived from the leaves of Calligonum comosum L. The primary objective of this investigation is to assess the photocatalytic efficacy of the synthesized catalyst in addressing organic pollutants. The Al2O3 NPs exhibit a spherical morphology with crystalline arrangements, as evidenced by an average crystallite size of 25.1 nm in the XRD analysis. The band gap energy of the Al2O3 NPs is determined to be 2.86 eV. In terms of mechanical properties, the Al2O3 NPs show significant potential in enhancing both flexural and compressive properties, thereby making them a viable choice for improving the mechanical performance of composites. Notably, the Young’s modulus of the hybrid composite (comprising plant material and Al2O3 NPs) exhibits a remarkable increase of 34.4% in flexion and 78.3% in compression compared to the plant material alone. The catalytic performance of the Al2O3 NPs is evaluated using methylene blue (MB) as a cationic dye and Rose Bengal (RB) as an anionic dye. Impressively, the Al2O3 NPs demonstrate degradation efficiencies of 98.2% for MB and 90.5% for RB. The degradation processes occur under solar light irradiation, with a contact time of 120 m, a maintained pH of 7, and a temperature of 25 °C. This study found that Al2O3 nanoparticles are a promising, cost-effective, and environmentally friendly option for water treatment.

Influence of Long Milling Time on the Electrical Resistivity of Nanocrystalline Ni2MnSn Heusler Alloy Obtained by Mechanosynthesis

A Ni2MnSn Heusler alloy was obtained as a single B2 phase after 12 h of mechanical milling. The influence of prolonged milling on the phase stability was analysed for milling times up to 50 h, related to mean crystallite size, lattice strain, and electrical resistivity. The nature of the powders in the milled range was found to be nanocrystalline, with a mean crystallite size of about 33 ± 2 nm. An evaluation of the internal stresses induced by milling was performed, a linear behaviour was found, and a coefficient of the internal stress increase with milling time was proposed. Particle size distributions of milled samples were analysed, and the morphology of the powders was visualised by scanning electron microscopy. The elemental distribution of milled samples was quantified by energy-dispersive X-ray spectroscopy. Electrical resistivity measurements were performed on compacted samples, and their behaviour with milling time was analysed.

Solar light assisted enhanced photocatalytic activity of smart ternary ZnO:TiO2:SnO2 nanocomposites

In the present study, the smart combinations of metal oxide semiconductors (ZnO:TiO2)1-x(SnO2)x (ZTS) with different SnO2 loadings (as x = 0.0, 0.30, 0.25, 0.20, coded as ZTS0, ZTS1, ZTS2, and ZTS3) were synthesized by employing the simple sol-gel technique. The structural, morphological, optical properties and elemental composition were analyzed by using XRD, Raman spectroscopy, FE-SEM, BET, UV–Vis spectroscopy, IC-PMS, XPS and FTIR of ZTS nanocomposite and proved the formation of smart ternary combination of nanocomposites. Systematic investigation through the characterization emphasised that the acute interfacial combination was established between metal oxide semiconductors. The crystallite size was decreased on adding the amount of SnO2 in the pristine ZTS0 nanocomposites from 23.5 nm to 10.5 nm which was confirmed by Scherrer's equation. The optical energy band gap of the obtained ZTS nanocomposites was found to vary from 3.23 to 3.34 eV on adding the amount of SnO2. The performance of the ZTS nanocomposites as photocatalyst was examined towards organic dyes and the results shows highest degradation of MB and MO dyes with ZTS3 achieving 99 % and 97.3 % degradation efficiency with 1 g/L loading dose. The plausible mechanism was suggested considering the visible light absorption spectra and band diagram resulting in supressed of the recombination rate of charge carriers. The smart combination of ZTS nanocomposites makes it an ideal material for excellent photocatalytic activity for degrading organic contaminants in presence of solar light irradiation.

Demystifying ionic and electronic transport in prominent oxide ion and proton conducting ceramic electrolytes: Ce0.8Sm0.2O2 and BaCe0.7Zr0.1Y0.1Yb0.1O3-δ

ABSTRACT The development and performance of ceramic electrochemical cells (CECs) depend critically on choosing ceramic electrolytes with optimal ionic and electronic transport properties. In this study, we compare the structural, morphological, and transport characteristics of two representative ceramic electrolytes, oxide ion conducting Ce0.8Sm0.2O2 (SDC) and proton conducting BaCe0.7Zr0.1Y0.1Yb0.1O3-δ (BCZYYb). We demonstrate that SDC exhibits higher bulk conductivity but lower open-circuit voltage due to its higher electron density and larger crystallite size. In contrast, BCZYYb possesses higher proton conduction, lower activation energy (0.35–0.38 eV), and higher open-circuit voltage due to its lower electron density and smaller crystallite size with more grain boundaries. BCZYYb shows enhanced proton conductivity in humidified atmospheres due to the hydration of oxygen vacancies, making it more suitable for low-temperature CEC applications. These insights into ceramic electrolyte conduction mechanisms and microstructure-property relationships can guide the optimization of CECs for energy applications.

Ball billing induced highly dispersed nano-MgO in biochar for glucose isomerization at low temperatures

The isomerization of glucose is a crucial step for biomass valorization to downstream chemicals. Herein, highly dispersed MgO doped biochar (BM-0.5@450) was prepared from rice straw via a solvent-free ball milling pretreatment and pyrolysis under nitrogen conditions. The nano-MgO doped biochar demonstrated enhanced conversion of glucose in water at low temperatures. A 31 % yield of fructose was obtained from glucose over BM-0.5@450 at 50 °C with 80.0 % selectivity. At 60 °C for 140 min, BM-0.5@450 achieved a 32.5 % yield of fructose. Compared to catalyst synthesized from conventional impregnation method (IM@450), the BM-0.5@450 catalyst shows much higher fructose yields (32.5 % vs 25.9 %), which can be attributed to smaller crystallite size of MgO (11.32 nm vs 19.58 nm) and homogenous distribution. The mechanism study shows that the activated MgOH+·OH− group by water facilitated the deprotonation process leading to the formation of key intermediate enediol.

Influence of Post-Annealing Treatment on Some Physical Properties of Cerium Oxide Thin Films Prepared by the Sol–Gel Method

In this study, thin films of Cerium Oxide CeO2 were fabricated using the sol–gel technique and deposited onto a glass substrate. The annealing process was carried out at various temperatures ranging from 200 to 600 °C to investigate the structural, morphological, and optical properties of the films and their interrelations. X-ray diffraction (XRD) patterns revealed the crystalline nature of the prepared films, with film quality exhibiting enhancement with increasing annealing temperature. The average crystallite size, dislocation density, microstrain, and lattice constant were determined from XRD patterns. Higher annealing temperatures were found to increase the crystallite size values from 4.71 to 15.33 nm and decrease the dislocation density and microstrain of the unit cell. Scanning electron microscope (SEM) images illustrated the uniformity of the films, presenting a spheroid shape. Optical properties such as transmittance, absorbance, reflectance, the direct band gap, extinction coefficients, the refractive index, and optical conductivity were assessed using optical measurements. The direct optical band gap of the CeO2 film was observed to decrease from 3.99 to 3.75 eV with increasing film thickness. Using the Wemple and DiDomenico (WDD) single-oscillator model, dispersion energy parameters were calculated based on the refractive index. The nonlinear optical properties of the CeO2 thin films were evaluated using these dispersion energy parameters. The improvement of optical parameters holds significance in standardizing CeO2 thin films for various optoelectronic applications.

Study on multifunctional magnesium copper zinc spinel ferrite nanoparticles prepared by hydrothermal route; Physical, electrical, and anti-microbial investigation

Polycrystalline spinel ferrite nanoparticles of Mg0.70-XCuXZn0.30Fe2O4(X=0.0,0.15,0.30,0.45,0.60) were prepared by hydrothermal approach. The structural modification by X-ray diffraction of Mg-Zn spinel ferrite with Cu2+ substitution was recorded through crystallite size (11–14 nm), Lattice dimension (8.34–8.38 A°), strain (7×10−3-9×10−3) and dislocation density (4×1015-7×1015) respectively. The formation of spinel structure (Fe-O) was identified by FTIR with a vibration band around 400–600 cm−1. Also, the Rietveld refined XRD pattern confirmed the presence of a cubical spinel structure. The electron microscopic (SEM) analysis revealed sphere-cubical agglomerates of the prepared material. TEM analysis revealed that the particles were inside the nanoscale range, with an average particle size of 15.97 nm determined using a lognormal histogram. The existence of the expected elements is confirmed by EDS spectra. From BET data, surface parameters including surface area (39.938–92.643 m2/gm), volume (2.355 × 10−1 to 2.52 × 10−1 gm/cm3), pore radius (5.0831–12.650 nm), and pore size distribution were determined. The magnetic parameters Ms (20–34 emu/g), Hc (30–39 Oe), and Mr (1.3–2.8 emu/g) obtained by VSM measurements indicate the single domain, pseudo single domain and multi-domain nature of as prepared nanoparticles and lower dielectric parameters at high frequency obtain from dielectric spectroscopy indicate the suitability of the material for switching devices, power application energy storage, and high-frequency applications. The antibacterial efficacy of the synthesized nanoparticles (NPs) was evaluated against different harmful bacteria and demonstrated the desired zone of inhibition (ZOI).

Evaluation of the optical and magnetic properties of novel Nd0.9Zn0.1FeO3 perovskite nanoparticles and their adsorption of Pb2+ ions from water

Nd0.9Zn0.1FeO3 was prepared in a single-phase with an average crystallite size of 25.82 nm using a citrate combustion technique. The energy dispersive X-ray assures the chemical formula of the sample. The elemental mapping of Zn-doped NdFeO3 illustrates the good homogeneous distribution of the elements in the sample. Nd0.9Zn0.1FeO3 has antiferromagnetic properties with weak ferromagnetic components and has good UV absorbance. The values of the band gap for the direct and indirect transitions are 1.473 eV and 1.250 eV, respectively. The adsorption of nickel(II), cobalt(II), chrome(VI), cadmium(II), and lead(II) ions has been studied at pH 7. The highest removal efficiency (η = 73.72%) was observed for the lead ions from water. The current study has examined the kinetics, recoveries, and mechanisms of utilizing Nd0.90Zn0.10FeO3 to remove Pb2+ ions from water. The optimum conditions for the absorbing Pb2+ are pH 7 and a contact time of 60 min. The Freundlich isotherm model is the best model for the absorption of Pb2+ ions. While, the pseudo-second-order kinetic model describes the kinetic adsorption data. The sample has a good efficiency for removing Pb2+ ions from water several times.

Structural, Morphological and Ferroelectric Properties of Sr-Cd Co-Doped Nickel Ferrite for Energy Storage Devices

Ferroelectric materials, renowned for their capacity to demonstrate spontaneous electric polarization reversible through an external electric field, are essential in numerous technological applications owing to their distinctive characteristics. For this, a series of spinel Sr-Cd co-doped nickel ferrite nanomaterials Cd0.5−xSrxNi0.5Fe2O4 (x = 0.0, 0.1, 0.2 and 0.3) were prepared through the standard sol-gel auto combustion method The XRD patterns showed that the prepared samples have a cubic spinel structure. The crystallite sizes of the samples vary from 29 to 40 nm. The morphology of prepared samples showed uniformly distributed spheres. Magnetic properties showed the soft magnetic nature of the prepared ferrites. The ferroelectric study revealed that Sr-Cd substituted ferrites exhibited the elliptical nature of ferroelectric loops at normal room temperature. The maximum polarization has been achieved at x = 0.3. The understanding of current and voltage (I–V) showed a slowly decreasing tendency of leakage current on both sides symmetrically against the increasing Sr content. The conductivity of the prepared spinel increases as a function of higher Sr doping. The real part of dielectric constant increases with increasing frequency. The materials show large elliptical loops indicating high asymmetric ferroelectric energy storage capability.

Exchange bias behaviour in cobalt ferrite-cobalt oxide CoFe2O4/CoO nanocomposites for data storage applications

Abstract In this study cobalt ferrite-cobalt oxide CFO/CoO nanoparticles were synthesized using hydrothermal chemical method for studying the exchange bias (EB) phenomena: a key parameter for data storage applications. The structural analysis was carried out by Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Energy dispersive spectroscopy (EDS), which confirm formation of platelets like CFO/CoO nanoparticles with appropriate chemical composition of different elements with an average crystallite size of 15 nm. Magnetic study revealed the ferromagnetic behaviour of nanoparticles from (5K-360K) and blocking temperature has found to be above 360 K, which decreases nonmonotonically with increasing the applied field HFC. The field cool (FC) magnetic hystersis (MH) loop studies have revealed that the samples exhibit very large exchange bias effect. The values of exchange bias (HEB) found to be maximum at low temperature and decreases with increasing temperature before vanishing at the blocking temperature. The aim of the study is to determine role of cooling field strength for the exchange bias in magnetically contrasted CFO/CoO nanoparticles suitable for data storage applications.