Sol-gel Technique Research Articles

Micropatterning of LaCoO3 thin films through a novel photosensitive sol-gel lithography technique and their magnetic properties

This paper presents a study on the microstructure and magnetic properties of LaCoO3 (LCO) thin films, and also the micropatterning of LCO thin films using a novel photo-sensitive sol-gel lithography method. It is found that higher heat-treatment temperature can promote the healing of cracks and filling of pores, resulting in refining the grains, and improving the density of LCO film. The film treated at 850 °C has a larger nucleation energy, which makes the distribution of nucleation sites more uniform, promoting the healing of cracks and filling of pores, refining the grains, and improving the density of LCO film. LCO precursor sol, metal chelates with UV photosensitivity were synthesized by adding BzAcH photosensitizer. LCO micro-arrays with diameters of 50 μm, as well as other fine patterns with a minimum line width of about 2 μm were successfully prepared by a UV mask lithography technique. In contrast, our novel lithography method eliminates the need for photoresist, as the fine pattern is formed during the preparation of the LCO gel film, which is the advantages of our lithography method over traditional techniques.

Cr-doped Li-based [formula omitted]-(Beta) type hexaferrites: XRD, FTIR, XPS and dielectric evaluations for high-frequency applications

The rapid growth of electronic technology and communications have led to increase demand for high performance microwave absorbing materials. Ferrites are frequently used to absorb microwaves and protect against electromagnetic contamination. In the present study, β-type hexaferrite samples with different chemical compositions of LiFe11-xCrxO17 (x = 0.0, 0.1, 0.3, and 0.5) have been manufactured through the sol-gel auto-combustion technique. The effect of substituting Cr3+ on its structural, electrical and dielectric characteristics was examined. The XRD evaluation helped to develop a single-phase structure for all samples. The substitution of Cr3+ has changed the structural characteristics. FTIR analysis was used to investigate the vibrational properties of Cr-doped β-type hexaferrite. Two absorption bands in the infrared spectroscopy were used to indicate the tetrahedral and octahedral sites. XPS results revealed the incorporation of every metal ion related to their particular electronic states. The dielectric studies were determined in terms of frequency (1–6 GHz) and every sample behavior was described using the Maxwel-Wagner and Koop theories. Impedance analysis was utilized to study the effects of relaxation time and grain boundaries on the electrical features of the produced nanomaterials. Impedance Cole-Cole plots prove that all samples exhibit non-Debye-type multiple relaxation processes. It was observed that among all the synthesized samples, LiFe10.9Cr0.1O17 has a minimum reflection loss of −37.80 dB at 1.22 GHz. Cr-doped β-type hexaferrite results suggested using and designing hexaferrite-based nanocomposite for high-frequency absorbers in the microwave range.

Synthesis, characterization and photoelectrochemical performance of Bi2Fe4O9 thin films

Mullite-type Bi2Fe4O9 has been little explored in thin film form as a photoanode for photoelectrochemical water splitting. In this study, Bi2Fe4O9 thin films have been prepared using the sol-gel technique from a simple precursor solution based on the corresponding metal salts, acetic acid, and polyvinyl alcohol. The films were deposited by dip-coating onto fluorine-doped tin oxide substrates and dried at 350 °C, repeating the dipping-drying cycle six times, and finally sintered at 600 °C. The films were characterized by GIXRD, revealing the formation of the material in its orthorhombic phase. Raman spectroscopy showed the Ag and B1g vibrational modes, validating the formation of the bismuth iron oxide. UV–Vis transmittance measurements revealed that the material exhibits two optical transitions: a direct band gap of 2.86 eV and an indirect band gap of 1.98 eV. FESEM micrographs and AFM images showed a uniform nanostructured surface morphology. The photoelectrochemical properties of the Bi2Fe4O9 films were studied using cyclic voltammetry and chronoamperometry with front side illumination, demonstrating the stability of the material in aqueous media and the generation of photocurrent in the presence of H2O2. Furthermore, results from intensity-modulated photocurrent spectroscopy (IMPS) revealed that the photocurrent is limited by both bulk and surface recombination and a short hole diffusion length.

The room temperature signature of micro to nanocrystalline calcium copper titanate (CCTO) thin film by a modified sol-gel technique and tailoring its material property

This study aims to identify an alternative route for the low-temperature synthesis of calcium copper titanate (CCTO) thin films and to explore a new understanding of precursor composition strategy and its relationship to thin-film combustion synthesis using a modified sol-gel technique. Micro-sized to nano-sized CCTO thin films were effectively deposited onto various substrates using a rapid and modified sol-gel process at remarkably low temperatures (∼100 °C), with room temperature phase formation of CCTO observed via FTIR and Raman spectroscopy. Calcium nitrate, copper nitrate, and titanium (IV) butoxide served as precursor materials to create the sol for spin coating. The resulting CCTO thin films were polycrystalline, uniform, and compact. The surface morphology and optical properties of these films were analyzed using Atomic Force Microscopy (AFM), Field Emission Scanning Electron Microscopy with Energy Dispersive X-Ray Analysis (FESEM-EDAX), X-Ray Diffraction (XRD), and UV–VIS spectrophotometry. XRD confirmed various phases of CCTO on different substrates, with significant intensity variations in the peaks at different annealing temperatures. The XRD patterns on three different substrates-glass, SnO2 coated glass, and SiO2 coated Si—revealed different CCTO phases such as CCTO (301), CCTO (220), CCTO (400), and CCTO (422). EDAX analysis confirmed the presence of Ca, Cu, Ti, and O. The band gap varied from 2.5 to 3.8 eV depending on the annealing temperature. Capacitive vs. frequency response, dielectric loss, and I-V characteristics of the films were measured using MIM (Metal-Insulator-Metal) or SIM (Semiconductor-Insulator-Metal) structures.

Morphology tuned dielectric, electrical, impedance, relaxation metrics of Co–Mg doped strontium ferrite, and their computational modeling

Sol-gel technique was used to develop M-type hexaferrites SrCoxMgxFe12-2xO19. The impact of doping of Co–Mg is analyzed on structural, dielectric, and electrical properties. The analysis was done in the frequency range of 150 Hz to 2 MHz. X-ray diffraction (XRD) analysis was performed for the determination of phase and structure of the prepared ferrites. The obtained results indicated the presence of an M-type hexagonal structure. The inclusion of Co–Mg caused a decrement in the crystallite size from 30.48 to 17.22 nm. The morphological analysis was performed using scanning electron microscopy (SEM), which reveals the formation of needle-shaped platelet structures. The doping had a non-monotonical effect on the dielectric constant and loss tangent. All the prepared compositions showed non-Debye-type relaxation for electric modulus. The increase in doping of Co–Mg caused a reduction in relaxation time. From the impedance spectroscopy, it was observed that both grains and grain boundaries affected the electrical characteristics.

Synergistic effects of Co-Mn co-doping on the structural and optical properties of TiO2 nanospheres: Dual functions for DSSC photoanodes and degradation photocatalyst

Synthesizing direct solar irradiance-responsive nanomaterial capable of serving as an efficient photoanode for dye-sensitized solar cells (DSSCs) and active photocatalysts for organic pollutant elimination poses a formidable challenge. This study focused on the synthesis of cobalt and manganese co-doped titanium dioxide (TiO2) nanoparticles via sol-gel technique, enhancing their efficacy in both the DSSCs and methylene blue (MB) dye degradation. X-ray diffraction and Raman analysis confirm the existence of a tetragonal crystal structure with the anatase phase of TiO2, while XPS analysis verifies the successful integration of cobalt and manganese ions into the host lattices. BET analysis has confirmed that Co, Mn co-doped TiO2 exhibits a higher pore volume and specific surface area compared to the undoped TiO2 material. FESEM and HR-TEM reveals spherical shape morphology and EDS mapping confirms the purity of synthesized nanoparticles. Moreover, Co-Mn co-doped TiO2 nanoparticles exhibits a shift in the optical absorption edge towards the visible spectrum in UV-DRS analysis. PL analysis suggests a diminished electron-hole recombination within the doped and co-doped sample. Electrochemical impedance spectroscopy demonstrates improved charge transfer properties. DSSCs employing the co-doped TiO2 exhibit significantly enhanced power conversion efficiency (4.99 %) compared to bare TiO2 (2.03 %), cobalt-doped (2.61 %), and manganese-doped TiO2 (3.97 %). Additionally, it demonstrates exceptional photocatalytic activity, with 87.83 % (Co-Mn co-doped TiO2) degradation efficiency with a lesser time extent for the methylene blue dye degradation. These findings underscore the potential of Co-Mn co-doped TiO2 for addressing dual challenges in renewable energy (DSSC) and environmental remediation (Pollutant removal).

Structural and magnetic insights of the novel phosphate Ca2NiFe2(PO4)4

One of the primary goals of scientists in the field of materials chemistry is to explore new functional materials, the discovery of new crystal structures and the understanding of their structure-properties relationship. This paper outlines the synthesis of a novel orthophosphate, Ca2NiFe2(PO4)4, in the single crystal and powder forms. The crystallographic analysis reveals that this newly synthesized phosphate exhibits an orthorhombic crystal lattice with the Pbca space group. The crystal structure is composed of PO4 tetrahedra connected to Fe1O6, Fe2O5 and NiO5 polyhedra through shared vertices. This interconnection forms a three-dimensional framework that encloses cavities housing Ca2+ cations. A sol-gel technique was employed to obtain the pure powder. The Rietveld refinement indicates an excellent correlation between the calculated and observed X-ray diffraction patterns. This material was further characterized structurally using infrared and Raman spectroscopy, and morphologically by scanning electron microscopy. The magnetic measurements revealed two magnetic transitions at T1∼8.9 K and T2∼16.5 K suggesting the presence of magnetic frustration with overall dominant antiferromagnetic behavior.

Advanced Bioceramics: Properties, Fabrication and Applications

Bioceramics are engineered materials that achieve their applications in the medical field. Bioceramics are promising inorganic materials to create scaffolds for bone regeneration due to their desirable properties, such as biocompatibility, osteoconduction, and their similarity with bone composition. Bioceramics can operate as tissue replacement and can be used for coating metal implants to increase their biocompatibility. Bioceramics are classified into three types: bioinert ceramics, bioactive bioceramics, and biodegradable ceramics. There are different methods for the fabrication of bioceramics, they can be prepared by conventional powder processing methods or by some new unconventional methods. Bioceramics can be fabricated by a sintering process, which takes place through the hardening of the green bodies at a relatively high temperature lower than their melting point. Nowadays, microwave sintering is excellent in both heating efficiency, saving energy and time, and the concomitant processing cost. There are other methods used to obtain bioceramics; such as sol-gel, gas-foaming, gel-casting, and freeze-casting techniques. Recently, the CAD/CAM technique (computer-aided design/manufacture) was used in the fabrication of bioceramics and is applied in the dentistry field. The application of bioceramics connects to the repair of the skeletal system, which consists of joints, bones, and teeth, as well as both soft and hard tissues. Bioceramics can be used to replace parts of the cardiovascular system, especially heart valves.

Synergistically enhanced electromagnetic absorption in barium ferrite/hollow carbon spheres/epoxy composites

The ongoing technological advancements have emphasized the importance of absorbent coatings, which are essential for effectively absorbing electromagnetic waves across various industries, including electronics, healthcare, and security systems. In this research, barium ferrite particles and hollow spherical carbon particles have been synthesized to investigate the synergistic effect of different compounds in absorbing electromagnetic waves in the epoxy coating. The barium ferrite particles were synthesized in two distinctive rod and spherical morphologies at 600 and 900 °C, employing the sol-gel technique. Also, hollow spherical carbon particles were synthesized. Synthesized particles were analyzed structurally and chemically with an X-ray Powder Diffraction, Fourier infrared spectrometer, vibrating‐sample magnetometer, field emission Scanning Electron, and Raman spectroscopy.The absorption characteristics of a coating that contains rod and spherical morphologies of barium ferrite and hollow spherical carbon particles can be adjusted by controlling the amounts of synthetic compounds in the 8–12 GHz range. The results indicate that combining rod-shaped barium ferrite particles (900 °C) and hollow spherical carbon particles in a thin epoxy coating improves impedance matching and wave attenuation. Notably, when the epoxy coating is 1.5–2 mm thick and contains 20 % rod-shaped barium ferrite particles (900 °C) and 1 % hollow spherical carbon particles, reflection loss values of < -20 dB are observed at frequencies of 10–12 GHz.

Insight into the Role of Rb Doping for Highly Efficient Kesterite Cu2ZnSn(S,Se)4 Solar Cells.

Various copper-related defects in the absorption layer have been a key factor impeding the enhancement of the efficiency of Cu2ZnSn(S,Se)4 (CZTSSe) solar cells. Alkali metal doping is considered to be a good strategy to ameliorate this problem. In this article, Rb-doped CZTSSe (RCZTSSe) thin films were synthesized using the sol-gel technique. The results show that the Rb atom could successfully enter into the CZTSSe lattice and replace the Cu atom. According to SEM results, a moderate amount of Rb doping aided in enhancing the growth of grains in CZTSSe thin films. It was proven that the RCZTSSe thin film had the densest surface morphology and the fewest holes when the doping content of Rb was 2%. In addition, Rb doping successfully inhibited the formation of CuZn defects and correlative defect clusters and promoted the electrical properties of RCZTSSe thin films. Finally, a remarkable power conversion efficiency of 7.32% was attained by the champion RCZTSSe device with a Rb content of 2%. Compared with that of un-doped CZTSSe, the efficiency improved by over 30%. This study offers new insights into the influence of alkali metal doping on suppressing copper-related defects and also presents a viable approach for improving the efficiency of CZTSSe devices.

Effect of the glycerol dispersant on the structure, electrical transport and magnetoresistive properties of La0.67Ca0.33MnO3 ceramics prepared by the sol-gel routine

In this paper, the sol-gel technique is employed to synthesize polycrystalline La0.67Ca0.33MnO3 (LCMO) ceramics, where methanol is chosen as the solvent. The crystal structure, morphology, as well as electrical and magnetoresistive properties were examined. Moreover, the effect of amount of the dispersant glycerol on the properties of LCMO ceramics is studied. X-ray diffraction (XRD) results showed that all samples crystallized in single phases with orthogonal perovskite structure (pnma space group), without any detectable impurity phases. Results reveal that the grain size of LCMO ceramics exhibits an initial increase followed by a decrease, accompanied by a similar behavior in the temperature coefficient of resistance (TCR) and magnetoresistance (MR). When the volume ratio of glycerol and methanol reached 2 %, the grain size is determined to be 7.30 μm, with TCR value of 25.02 % K−1 at T= 263.2 K, and MR value recorded at 55.40 %. The study elucidates the influence of glycerol on LCMO polycrystalline ceramics and optimize the fabrication process, thereby improve the electric transport property and magnetoresistance.

Effect of Calcination Temperature on the Structural, Morphological, and Magnetic Properties of Rare-Earth Orthoferrite NdFeO3 Nanoparticles Synthesized by the Sol-Gel Method

The sol-gel technique has been used to synthesize rare Earth orthoferrite NdFeO3 nanopowders. The present investigation examines how calcination temperatures affect the structural, morphological, and magnetic properties of NdFeO3 orthoferrites. X-ray diffraction studies indicate that there is no discernible difference in the observed structures with calcination temperatures other than the bond distances and bond angles. The surface morphology and field-emission scanning electron microscopy (FESEM) indicate that porosity of the samples is regulated by the physical shape of the tiny particles within them. Porosity is minimized as calcination temperature increases, showing a higher density that contributes to reducing leakage current features while improving the break-down strength. These variations are attributed to bond length and bond angle variation of the Fe-O. The photocatalytic activity of the NdFeO3 nonoparticles was assessed by photodegrading a number of organic dyes, including methyl orange (MO), rhodamine B (RhB), and methylene blue (MB). The product displays significant photocatalytic degradation of the dyes whenever exposed to visible light. Overall, this investigation aims to establish a relationship between the physical properties and microstructural parameters to provide valuable insights into the magnetic interactions present in the samples and the comprehensive behavior of NdFeO3 orthoferrites samples calcination at different calcination temperatures.

TL, EPR, and optical properties of undoped and Eu-, Ce-, Tb-, Sm-, Cu-, Mn-, and Li- doped MgSiO3 phosphors, synthesized by sol-gel combustion technique

Polycrystalline MgSiO3 samples, undoped or doped with rare earth- (Eu, Tb, Ce, Li, Sm), transition- (Mn and Cu), and alkali metal- (Li) elements, were prepared by the sol-gel combustion method and characterized by thermoluminescence, electron spin resonance, and optical properties. Enstatite and protoenstatite phases are observed in undoped and doped MgSiO3. Better TL results have been observed for phosphors doped with Tb, Ce, and Li (0.5 % mol). Fading experiments and the GCD method have been performed. EPR signals of gamma-irradiated phosphors indicate the formation of radiation-induced defect centers. Cu-doped MgSiO3 shows an unusual feature of the Cu2+ ion. The Cu2+ ion occupies a tetragonally compressed octahedral site, presenting an unconventional attribute. Optical bandgap value Eg is higher for the Ce, Tb, Mn, Li, Sm, and Cu-doped MgSiO3 phosphors. Ce, Li, and Tb dopant ions were found suitable for the MgSiO3 sample regarding its thermoluminescent response and its possible application in radiation dosimetry.

Influence of support properties on the activity of 2Cr-Fe/MgO-MO2 catalysts (M = Ce, Zr, CeZr and Si) for the dehydrogenation of n-octane with CO2

The influence of the support on catalytic activity and stability of supported 2Cr-Fe bimetallic catalysts for the CO2-assisted dehydrogenation (DH) of n-octane has been investigated. Four MgO modified supports viz; MgO-CeO2 (MgCe), MgO-ZrO2 (MgZr), MgO-CeO2-ZrO2 (MgCeZr) and MgO-SiO2 (MgSi) were synthesized by the sol-gel combustion technique. The supported catalysts were in turn prepared by vacuum impregnation and thereafter tested for the CO2-assisted DH of n-octane. The catalysts were characterized by inductively coupled plasma optical emission spectroscopy (ICP-OES), X-ray diffraction (XRD), N2-physisorption, Raman spectroscopy, transmission electron microscopy (TEM), electron dispersive x-ray (EDX), temperature programmed desorption of CO2 (CO2-TPD), temperature programmed reduction and oxidation (H2-TPR and CO2-TPO), electron paramagnetic resonance (EPR) and thermal gravimetric analysis (TGA) techniques. Raman results showed that the CrOx is stabilized as mono- and/or polynuclear Cr(VI) species over the 2Cr-Fe/MgCe catalyst, which are reduced to lower oxidation state species during the DH reaction. The 2Cr-Fe/MgZr, 2Cr-Fe/MgCeZr and 2Cr-Fe/MgSi catalysts stabilized the CrOx as polymerized species, forming the more active Cr-O-Fe polymer units on the catalysts’ surface. XRD, TEM and EDX results showed that the ZrO2-containing supports have smaller particles and stabilized the active metal oxides in a more dispersed amorphous state. The CO2-TPO of the pre-reduced catalysts and EPR of the used catalysts indicated that the 2Cr-Fe/MgCeZr undergoes significant re-oxidation by CO2 during the catalytic process. The 2Cr-Fe/MgCe was the least active, while the 2Cr-Fe/MgZr catalyst showed the best performance and stability over three regeneration cycles. Selectivity to C8 products (octenes and aromatics) was found to strongly depend on the surface basicity of the catalysts. Deactivation of the catalysts was found to follow first order kinetics and coke deposition was identified as the major cause.

Structural, dielectric and Magnetic properties of Samarium doped (Ni–Zn) based Spinel Ferrite (Ni0.5Zn0.5SmxFe2-xO4) nanomaterials

Samarium doped Ni-Zn ferrites (Ni0.5Zn0.5SmxFe2-xO4) were synthesized using sol-gel auto-combustion technique with Sm3+ doping concentrations varying as x = 0.00, 0.05, 0.10, 0.15, and 0.20. The prepared nanomaterials were examined using X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), complex impedance spectroscopy (CIS) and vibrating sample magnetometer (VSM). The XRD examination verified the pure FCC spinel phase of all samples with no impurity peak. The FTIR analysis for spinel molecules formation identified two frequency bands at the octa and tetrahedral sites. The TEM analysis confirmed the shape, size and distribution of prepared nanoparticles. The different dielectric properties were analyzed with a frequency range of 1 MHz–3 GHz and the impact of doping was also studied simultaneously. Magnetic nature of prepared materials was investigated at room using the VSM. It is found that the prepared nanomaterials are suitable for high energy storage as well as magnetic applications.

Crystal Structural Characteristics and Electrical Properties of Novel Sol-Gel Synthesis of Ceramic Bi0.75Ba0.25(FeMn)0.5O3.

In this investigation, our primary objective is to explore the structural, morphological, and electrical characteristics of Bi0.75Ba0.25(FeMn)0.5O3 ceramic material synthesized by the sol-gel method. The prepared sample underwent synthesis through the conventional sol-gel technique. Examination through X-ray diffraction (XRD) unveiled a well-defined rhombohedral structure within the R3´C space group. Moreover, to evaluate the purity and nano-grain morphology, we utilized energy dispersive spectroscopy (EDX) and scanning electron microscopy (SEM). Electrical assessments were carried out over a frequency span of 100 Hz to 1 MHz and temperatures ranging from 200 to 340 K. Employing the correlated barrier hopping (CBH) model, we analyzed the AC conductivity of our specimen. The activation energy, determined from both DC conductivity and impedance spectra, demonstrated close correspondence, suggesting that both conductivity and r laxation processes are influenced by similar factors. Notably, the dielectric properties hold significant importance, potentially rendering our sample suitable for electronic applications. Furthermore, we calculated thermodynamic parameters, such as enthalpy (ΔH), entropy change (ΔS), and free energy of activation (ΔF), offering deeper insights into the material's behavior and conductivity mechanisms.

Synthesis of spinel Nickel Ferrite (NiFe2O4)/CNT electrocatalyst for ethylene glycol oxidation in alkaline medium

Nickel-iron-based spinel oxide was prepared and supported on multi-walled carbon nanotubes to enhance the electrochemical oxidation of ethylene glycol in an alkaline medium. NiFe2O4 was prepared using facile sol-gel techniques. Then the prepared material was characterized using different bulk and surface techniques like powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), and transmitted electron microscope (TEM). Different electrodes of NiFe2O4/CNT ratios were prepared to find out the optimum spinel oxide/CNT ratio. The activity of the metal spinel oxides composite was characterized toward ethylene glycol conversion by different electrochemical techniques like cyclic voltammetry (CV), Chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS). The modified electrode reached an oxidation current of 43 mA cm−2 in a solution of 1.0 M ethylene glycol and 1.0 M NaOH. Furthermore, some kinetics parameters (like diffusion coefficient, and rate constant) were calculated to evaluate the catalytic performance. Additionally, the electrode showed extreme stability for long-term ethylene glycol oxidation.

Transparent self-cleaning coating prepared from SiO2/B4C and SiO2/B4C/TiO2 for the solar cell

Transparent self-cleaning coatings based on photocatalytic activity have attracted great attention in recent years owing to their promising applications in many fields, such as solar cell cover glass. This study reports a simple method to prepare transparent self-cleaning silicon dioxide (SiO2) coatings filled by boron carbide (B4C) and titanium dioxide (TiO2) nanoparticles. A sol-gel technique was used to synthesize a SiO2 solution containing B4C and TiO2 nanoparticles, and a dip-coating technique was followed to coat the composite solution on glass slides. The SiO2 coating was successfully obtained in the presence of both semiconductor nanoparticles as confirmed by FTIR and XRD measurements. Both the photocatalytic activity and self-cleaning property of the composite coatings were evaluated by photocatalytic degradation of a model dye, methylene blue, under visible light irradiation. The SiO2 coating containing both B4C and TiO2 nanoparticles exhibited an improved photocatalytic activity compared to the SiO2 coating including only B4C. In particular, a 46% degradation rate of the model dye methylene blue was achieved for the SiO2 coating containing 15 wt% B4C and 5 wt% TiO2 nanoparticles. Highly transparent composite coatings on glass slides were prepared. The SiO2 coating containing both B4C and TiO2 nanoparticles was found to exhibit ~8% reduction in the optical transmission of the glass slide and ~1% reduction in the efficiency of a solar cell containing the coated glass slide. These findings demonstrated that the SiO2 composite coatings have potential for self-cleaning applications in removing contaminants from the glass cover of the solar cell under visible light irradiation.Graphical

Physical properties of La3+ ion doped Ni[sbnd]Zn based spinel ferrite nanomaterials for technological applications

Spinel ferrite nanoparticles are extensively utilized in various everyday applications due to their exceptional capabilities. They are highly effective and efficient for various applications such as energy storage devices, microwave, electrode design, fuel cells, and recording media. Based on these applications, five samples of lanthanum doped nickel‑zinc spinel ferrite Ni0.5Zn0.5LaxFe2-xO4 nanoparticles were synthesized using the sol-gel auto-combustion technique. The lanthanum concentrations varied as x = 0.00, 0.05, 0.10, 0.15 and 0.20. X-ray diffraction (XRD) analysis revealed the formation of single phase cubic spinel structure of the prepared samples. The crystallite size was determined using the Scherrer formula and the values lies in the range of 9.22 to 20.09 nm. The chemical composition of the prepared samples was confirmed using Fourier transform infrared spectroscopy (FTIR) analysis. Transmission electron microscopy (TEM) confirmed the agglomeration and spherical shape morphology of the nanoparticles with an average particle size of 40 nm. Magnetic properties along with La3+ ion concentrations were investigated using the vibrating sample magnetometer (VSM). The dielectric properties of the prepared samples were carried out using impedance analyzer with an applied frequency ranging from 1 MHz to 3 GHz. Furthermore, the polarization mechanism in the applied frequency range was discussed with relaxation behavior at high frequency. The impact of La3+ concentrations on different parameters such as dielectric constant, impedance, electric modulus, tangent loss, and Ac conductivity were also investigated. The investigation of dielectric parameters. The relaxation mechanism at high frequency provided a significant impact of such type of materials to store energy due lake of hopping between the tetra and octahedral sites by addition of La3+ doping. The prepared samples exhibit excellent magnetic as well dielectric properties which makes suitable for microwave devices and soft magnetic applications.

Mechanically Robust and Electrically Conductive Hybrid Hydrogel Electrolyte Enabled by Simultaneous Dual In Situ Sol-Gel Technique and Free Radical Copolymerization.

Mechanically robust and ionically conductive hydrogels poly(acrylamide-co-2-acrylamido-2-methylpropanesulfonate-lithium)/TiO2/SiO2 (P(AM-co-AMPSLi)/TiO2/SiO2) with inorganic hybrid crosslinking are fabricated through dual in situ sol-gel reaction of vinyltriethoxysilane (VTES) and tetrabutyl titanate (TBOT), and in situ radical copolymerization of acrylamide (AM), 2-acrylamide-2-methylpropanesulfonate-lithium (AMPSLi), and vinyl-SiO2. Due to the introduction of the sulfonic acid groups and Li+ by the reaction of AMPS with Li2CO3, the conductivity of the ionic hydrogel can reach 0.19Sm-1. Vinyl-SiO2 and nano-TiO2 are used in this hybrid hydrogel as both multifunctional hybrid crosslinkers and fillers. The hybrid hydrogels demonstrate high tensile strength (0.11-0.33MPa) and elongation at break (98-1867%), ultrahigh compression strength (0.28-1.36MPa), certain fatigue resistance, self-healing, and self-adhesive properties, which are due to covalent bonds between TiO2 and SiO2, as well as P(AM-co-AMPSLi) chains and SiO2, and noncovalent bonds between TiO2 and P(AM-co-AMPSLi) chains, as well as the organic frameworks. Furthermore, the specific capacitance, energy density, and power density of the supercapacitors based on ionic hybrid hydrogel electrolytes are 2.88Fg-1, 0.09Whkg-1, and 3.07kWkg-1 at a current density of 0.05Ag-1, respectively. Consequently, the ionic hybrid hydrogels show great promise as flexible energy storage devices.