Barium titanate (BaTiO₃, BT) is a promising lead-free ferroelectric, but its sharp phase transition and temperature-dependent dielectric properties restrict its practical use. To overcome these limitations, Ba₁₋₃ₓNd₂ₓTi₁₋yZryO₃ ceramics (x = 0.025; y = 0–0.125) were synthesized to explore the combined effects of Nd3⁺ substitution at the A-site and Zr4⁺ substitution at the B-site. XRD confirmed the perovskite phase formation with a tetragonal–pseudocubic (nearly cubic, but with very small hidden distortion) transition as Zr content increases to 0.05 (BT3) and the pseudocubic transition continued up to 0.125 Zr content (BT6). Nd doping introduced the lattice distortion and reduced leakage by suppressing oxygen vacancy formation, while Zr substitution expanded the unit cell and broadened the ferroelectric–paraelectric transition, yielding relaxor-type behavior (means a material that shows diffuse, frequency-dependent ferroelectric behavior instead of a sharp, normal phase transition). The P–E hysteresis analysis confirms that the ferroelectric nature of BaTiO₃ progressively transforms into a relaxor-type behavior with increasing Zr content. The composition BT3 (x = 0.025, y = 0.05) exhibits the optimal balance of ferroelectric and electrical properties, showing moderate polarization, high insulation resistance, and excellent temperature-stable dielectric performance. Dielectric studies showed enhanced permittivity, reduced loss, and improved thermal stability in co-doped samples. Electrical analyses indicated increased resistivity and suppressed conductivity. Overall, Nd–Zr co-doping effectively tunes structure and properties, enabling multifunctional BaTiO₃ ceramics for capacitors, sensors, and energy storage devices.

NiWO4 (NW), Bi2MoO6 (BM), and NiWO4/Bi2MoO6 heterostructures (HS’s) were successfully prepared using an economic hydrothermal method for applications as photocatalysts and ethanol gas sensors. XRD results revealed that the synthesized samples contained monoclinic phase NW and orthorhombic phase BM with no impurities. FESEM and TEM micrographs indicated porous aggregates with good hetero-interfacial contacts. Oxygen vacancies were found along with Ni2⁺, W⁶⁺, Bi3⁺, and Mo⁶⁺ ions through XPS study. Enhanced visible-light absorption and band gap energy reduction due to strong interfacial electronic coupling were observed by UV–Vis DRS analysis of all the synthesized materials. The best catalytic activity among all the synthesized samples was observed in 0.90NW/0.10BM HS showing a high rate constant of 0.00803 min⁻1 for photocatalytic degradation of methylene blue (MB) dye under visible light irradiation with 95 % dye degradation efficiency. This is attributed to increased charge separation, high oxygen vacancy, porous structures, and enhanced visible-light adsorption. Moreover, 0.90NW/0.10BM heterostructure has shown excellent ethanol gas sensing property at room-temperature sensing of 26.

Abstract Phase-pure orthorhombic SnWO 4 and Bi 2 MoO 6 nanostructures were hydrothermally synthesized via controlled nucleation at elevated temperatures. Comprehensive characterization including XRD, FESEM, FTIR, Raman, and UV-Vis DRS analyses was performed to elucidate structure-property relationships: structure, morphology, vibrational, and light interaction. From the XRD results, both samples have an orthorhombic structure matching standard references-which is reassuring. For morphology, FESEM depicted SnWO 4 as flaky, thin-layered, while Bi 2 MoO 6 was aggregated nanostructured spheres. FTIR detected peaks assigned to the following metal-oxygen bonds: Sn-O, W-O, followed by Bi-O and Mo-O. Raman spectroscopy gave further confirmation by pointing out signals from WO 4 tetrahedra and MoO 6 octahedra. Results are in pretty good agreement with each other. UV-Vis DRS depicted strong absorptions in the UV and visible regions for both samples. Band gaps, estimated by Kubelka-Munk, were around 1.83 eV for SnWO 4 and 2.58 eV for Bi 2 MoO 6 . The narrow bandgap of 1.83 eV for SnWO 4 and moderate bandgap of 2.58 eV for Bi 2 MoO 6 position these materials as promising photocatalysts for visible-light-driven environmental remediation and solar energy conversion applications

The Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSCF) and Ce0.8Gd0.2O2−δ (GDC) ceramics were synthesized by sol-gel method and their composites (100-x)BSCF-xGDC, where x = 10, 20, 30, 40 and 50 wt

In this work, new multiferroic nanocomposites based on (1-x) Ni0.5Co0.5Fe2O4 + (x) Ba0.85Ca0.15Zr0.1Ti0.9O3 (where x = 0.0,0.20, 0.40,0.60,0.80 and 1) have been synthesized by conventional solid state reaction route. Structural studies have been done by XRD and Rietveld analysis technique. Energy gaps were determined using UV-Vis spectrophotometer, and values for ferrite NCFO is 1.17 eV, BCZT pure phase is 3.01 eV, whereas energy gap values vary from 1.66 eV to 2.24 eV in the case of composites. Also, the presence of ferrite T2g, A1g, Eg vibrational modes and perovskite A1(TO), E(TO) vibrational modes were confirmed through Raman spectroscopy and proved strong interfacial coupling. Scanning electron microscopy (SEM) analysis has been carried out for determining morphological characteristics of the synthesized samples. Sample N60B40 possesses highest coercivity of 470.3 Oe, whereas N20B80 exhibits minimum coercivity of 431.4 Oe. Other samples possess moderate values, such as 453.3 Oe forN80B20 and N60B40 470.3 Oe. Moreover, the dielectric constant decreases and remains constant while increasing the frequency. The N80B20 composite was observed to have the maximum magnetodielectric constant of 8.30%, which is significant at low frequency with corresponding magnetodielectric loss variation, the results revealed a significant magnetodielectric coupling effect.

Abstract Visible light active-photocatalysts of Bi 2 WO 6 , Bi 2 MoO 6 , Bi 2 W 0.75 Mo 0.25 O 6 and Bi 2 W 0.25 Mo 0.75 O 6 were synthesized by hydrothermal method. Orthorhombic crystal structure and purity of compounds were confirmed by XRD. The FESEM images of all the compounds have confirmed the rods, spheres and the plate shaped nanoparticles. The XPS spectra has confirmed that +3, +6, +6 and –2 oxidation states of Bi, W, Mo, O respectively. The peak shifts observed in FTIR spectra of all the samples are attributed to formation of all compounds. The optical band gaps of these compounds were measured. The PCA of Bi 2 WO 6 , Bi 2 MoO 6 , Bi 2 W 0.75 Mo 0.25 O 6 and Bi 2 W 0.25 Mo 0.75 O 6 along with the ‘Blank’ experiment (without catalyst) for the degradation of Rh B was performed under visible light irradiation for each and every 30 min up to 240 min. The degradation of Rh B in the blank experiment was only 7% for 240 min, whereas the % of Rh B degradation with Bi 2 WO 6 , Bi 2 MoO 6 , Bi 2 W 0.75 Mo 0.25 O 6 and Bi 2 W 0.25 Mo 0.75 O 6 are 61%, 62%, 27%, and 14 % respectively. The PCA of Bi 2 WO 6 and Bi 2 MoO 6 exhibits significantly higher than Bi 2 W 0.75 Mo 0.25 O 6 and Bi 2 W 0.25 Mo 0.75 O 6 . The scavenger test results of Bi 2 MoO 6 , Bi 2 WO 6 which were the most photocatalytic active, confirmed the essential role played by • O 2 − and h + in Rh B degradation.

Ni0.5Co0.5Fe2O4 nanoparticles were prepared by the solgel and hydrothermal methods, aiming to demonstrate the systematic effects of the preparation methods on structural, vibrational, magnetic, optical, and photocatalytic characteristics. The results of the X-ray diffraction and Rietveld refinement showed that the phase and structure of the two samples are single-phase cubic spinels (space group Fd-3m); differences related to the preparation methods can also be detected through the changes in the crystallite size and lattice strain. The NCFO synthesized by the Hydrothermal method presents reduced crystallite size with enhanced crystallinity, which further widens the optical band gap (similar to 1.68 eV), while the grain growth in sol-gel NCFO leads to a narrower optical band gap (similar to 1.35 eV). SEM images revealed well-defined and uniformly distributed nanoparticles for hydrothermal NCFO with agglomerated and irregular morphologies for sol-gel samples. FTIR and Raman spectroscopy evidences distinct differences in the metal-oxygen bonding, cation distribution, and short-range structural order. Measurements of magnetic properties showed higher values of saturation magnetization, coercivity, and anisotropy for sol-gel NCFO due to enhanced ferrimagnetic ordering and domain wall pinning. In contrast, hydrothermal NCFO showed notably improved photocatalytic degradation rates of MB and RhB under UV irradiation owing to efficient charge carrier separation and suppressed recombination. The superior fingerprint visualization achieved using hydrothermally synthesized ferrites is attributed to their enhanced magnetic responsiveness, which facilitates effective particle attraction and selective deposition on latent ridge patterns. This comparative study establishes clear synthesis-structure property correlations in NCFO and provides strategic insights for tailoring ferrite nanomaterials toward magnetic and environmental remediation applications.

Novel tellurite glasses with compositional dependence of (90-x)TeO2-10TiO(2)-xWO(3) (0 <= x <= 30) were synthesized at 900 degrees C through melt quenching. XRD, EDX, FE-SEM, Color mappings, XPS, FTIR, Raman, DSC, optical absorption techniques were employed for characterizing the prepared samples. XRD, DSC and FE-SEM measurements testified the amorphous nature of the glasses. The Raman and FTIR analyses manifest the presence of TeO3, TeO3+1, TeO4, WO4, WO6 structural units alongside the non-bridging oxygen's (NBO's) with increasing WO3 content. The DSC studies showed that the addition of WO3 content for TeO2 reduced the crystallization by retaining the amorphous nature of these glasses which is a key for drawing optical fibers. Te-O-W/Ti-O-W/W-O-W linkages are observed to be accountable for increasing in glass transition temperature (T-g) of these glasses. On increasing WO3 content, the crystal peaks shifted to higher temperature region which increased Delta T. The calculated optical band gap (E-opt) of the glasses suggests that the width of the valence and conduction bands increases by reducing the optical band gap energy. The Urbach energy (Delta E) values are observed to be increased and demonstrated that the glasses with higher mol% of WO3 are having more structural disorder defects. The electron donating ability of O2- ions in Te-O/W-O/Ti-O increases with increasing WO3. The variations in alpha(2-)(O) and A(th) clearly manifest that the degree of covalent bonds increases in the glass matrix with WO3 content. The FTIR, Raman, DSC and Optical absorption analyses confirmed that these glasses possess higher refractive index, larger thermal stability and lowering the phonon energy due to the addition of WO3 content. Thus, it is believed that these glasses might useful for making the optical lenses and promising material for fiber drawing applications.

An alternative solid electrolyte is imperative to replace YSZ for better IT-SOFC. Gd3+/Sm3+ doped ceria (Ce0.9Gd0.1O2-delta-GDC1, Ce0.8Gd0.2O2-delta-GDC2, Ce0.8Sm0.2O2-delta-SDC) were synthesized via sol-gel method. These compounds were investigated by using X-ray diffraction (XRD), Field emission scanning electron microscope (FESEM), Energy dispersive X-ray (EDX) spectra, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), Raman and impedance spectroscopy. FESEM micrographs manifested that GDC1 has larger grain sizes than GDC2 and SDC. Interestingly, SDC exhibited more grain boundaries than GDC1 and GDC2. These high dense sol-gel derived compounds have exhibited better ionic conductivity than some of the previously reported Gd3+/Sm3+ doped ceria. Furthermore, the selectivity of calcinated GDC1, GDC2 and SDC sensors at room temperature (RT) for ammonia, methanol, ethanol and formaldehyde gases at 100 ppm was examined and found that GDC1 has displayed an applausive selectivity with superior response for formaldehyde gas sensing at RT as an operating temperature. The Raman analysis avowed the presence of oxygen vacancies which were identified as instrumental in both applications. The multiple gases detected by GDC1 at RT might provide various strategies to design novel gas sensors.

The development of the room temperature (RT) gas sensors is absolute need. Hydrothermally and sol-gel derived Co3O4 and Gd0.1Ce0.9O2-δ (GDC) were used to fabricate the novel heterostructures in the ratio of 1:1 Co3O4/GDC, 2:1 Co3O4/GDC and 1:2 Co3O4/GDC. These samples were scientifically analysed through X-ray diffraction (XRD), Field emission scanning electron microscope (FESEM), Energy dispersive X-ray (EDX) spectra, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), Raman, UV–Vis-Diffuse reflectance spectra (DRS) and photoluminescence (PL). XRD, XPS together with FTIR and Raman spectra are the testimonial of the formation of Co3O4, GDC and their heterostructures. Interestingly, the performed gas sensing studies conclusively disclose that these sensors have adequate sensitivity to detect the tested gases at RT. Furthermore, O2− species played crucial role than O2− and O− in chemisorption and gas sensing mechanism. Additionally, 2:1 Co3O4/GDC and 1:2 Co3O4/GDC exhibited an enormous selectivity and highly responsive towards the detection of formaldehyde (CH2O) and ammonia (NH3), respectively. 2:1 Co3O4/GDC/1:2 Co3O4/GDC offered the high response (S) of 106.59/83.52 for CH2O/NH3 gas. In fact, the formation of anisotype p-n/n-p rather than isotype p-p/n-n junctions in 2:1 Co3O4/GDC and 1:2 Co3O4/GDC endowed these two heterostructures to exhibit quick response even at low ppm of selected gases. The outcome of this work might provide strategy for the design of novel sensing materials to detect multiple gases.

Melt quenching technique was employed to prepare glasses with compositional formula 30TeO(2)-39.5B(2)O(3)-(30-x)ZnO-xBaO-0.5V(2)O(5) (0 <= x <= 30 mol%). Various characterization tools viz., X-ray diffraction (XRD), Energy dispersive X-ray (EDX) includes color mapping images, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR), Raman, Differential scanning calorimetry (DSC), UV-Vis absorption and Electron paramagnetic resonance (EPR) were used in this investigation for the characterization of these glasses. The XRD patterns together with DSC thermograms asserted the amorphous nature of all glasses. FTIR and Raman vibrational analyses has unveiled the formation of B-O-Ba2+-O- and Te-O--Ba2+-O- wherein the bonds with Ba2+ ions are mostly ionic. DSC investigations disclosed that the increase of BaO at the cost of ZnO declined the crystal phases and favored the amorphosity and this behavior causes these glasses more advantageous for fiber drawing. The Urbach energy (Delta E) lies in between 0.28 and 0.57 eV and suggested the glasses containing high ZnO has less defects. EPR data validated that Ba2+ ions might surround V4+ ions as Ba2+-O-V4+=O by replacing Zn2+-O-V4+=O linkages. The other optical properties were discussed in detail by correlating the structural variations noticed from both FTIR and Raman data analyses.

Bi2O3 based glasses have been proven as promising optical materials with regard to their 6 s2 lone pair electrons. By melt quenching, the highly thermal stable glasses 50Bi2O3-15PbO-(35-x)B2O3- xLi2O (where 0 < x < 25 mol%) were prepared. The short range order of the glasses was verified with XRD and DSC measurements. DSC analysis showed that thermal parameters varied non -linearly with increase of Li2O. Density (rho), molar volume (Vm), oxygen packing density (OPD) and oxygen molar volume (Vo) were calculated and their compositional dependency was dis-cussed in detail. Energy dispersive X-Ray (EDX) spectrometry analysis validated the stoichiometry of sample composition. FTIR analysis illustrated that the glass network comprise of BiO3, BiO6, BO3 and BO4 structural units together with non-bridging oxygens. The computed optical prop-erties like optical band gap (Eopt), refractive index (n), Urbach energy (Delta E), molar refraction (RM), metallization criterion (M) and oxide ion polarizability (alpha O2-) were observed to be non-linearly varied with the addition of Li2O. The interplay between the structural roles of Li2O and Bi2O3 was instrumental for the observed variations in all the properties. BiPBL4 glass showed the highest thermal stability (175 degrees C) and the high kgl value among the glass series. The incorporation of Li2O in presence of low mol% of B2O3 with Bi2O3-PbO endowed these glasses to have the low phonon energy. The analysis carried out in this work showed that these glasses might useful for optoelectronic devices and optical fiber drawing applications.

Variation of tolerance factor was observed with doping of Sr and Bi at A and B sites respectively and independently in BaTiO3 compound. Stability of NBT based compositions is varied with the substitution of Ba content in A-site and alters with the concentration. Combining with the electronegativity difference and octahedral factor of ABO(3) structure, regularities governing the formation and the stability of perovskite type compounds are discussed. According to the results of BST and BBT series both dopants are reduce the tolerance factor and increase the distortion within the lattice of ABO(3)-type perovskite, the experience tolerance factor value and experience electronegativity difference value to form stable perovskite compound were obtained.

In the present study, simulation of polarization data using modified Glazounov equation (T & E simultaneously) of Barium Titanate based normal and relaxor ferroelectrics (i.e. BaTiO3 and Ba(NdxTi(1-2x)Nbx)O-3) as proposed by us was carried out. These materials were prepared through sol-gel and solid state double sintering route. Modified Glazounov equation describes and model the experimental PE data in terms of dipole moment and activation energy for thermally activated dipoles present the ceramic materials. This equation best fit to the experimental PE data. The increase and decrease of activation energy with temperature and composition was attributed to the degree of disorderness of dipoles.

Solid solutions of nano structured Na0.5Bi0.5TiO3-Ba0.925Nd0.05TiO3-BiFeO3 (0.7NBT-0.2BT1-0.1BF & 0.7NBT-0.1BT1-0.2BF) compositions were prepared by the conventional sol-gel method and the effect of BiFeO3 addition on microstructure, dielectric, ferroelectric and high temperature electrical properties of NBT-BT1-BF ceramics were investigated through XRD, SEM, dielectric and electrical characterization. X-ray diffraction patterns are well indexed and found that samples are crystallized in rhombohedral phase. SEM images have shown uniform distribution of grains and change in grain size with BiFeO3 concentration. The samples exhibited relaxor behavior, which is accompanied by a shift in epsilon(max) and Z '' towards high temperature with increasing BiFeO3 concentration. The grain and grain boundary response as well as the relaxation processes at different frequencies and temperatures were discussed. These observations suggest that BiFeO3 addition to NBT-BT1 ceramics can be considered as a potential lead free ceramic system in multi-ferroic devices.

Lead-free Na0.5Bi0.5TiO3 (NBT) and (1 − x)Na0.5Bi0.5TiO3 + xBaTiO3 with x = 0.1 and 0.2 (where x = 0.1 and 0.2 are named as NBT1 and NBT2, respectively), (1 − y)Na0.5Bi0.5TiO3 + yBa0.925Nd0.05TiO3 with y = 0.1 and 0.2 (where y = 0.1 and 0.2 are named as NBT3 and NBT4, respectively)-based relaxor ferroelectric ceramics were prepared using the sol-gel method. The crystal structure was investigated by X-ray diffraction (XRD) at room temperature (RT). The XRD patterns confirmed the presence of the rhombohedral phase in all the samples. The electrical properties of the present NBT-based samples were investigated by complex impedance and the modulus spectroscopy technique in the temperature range of RT–600 °C. The AC conductivity was found to increase with the substitution of Ba2+ ions to the NBT sample whereas it significantly decreased with the addition of Nd3+ ions. The more anion vacancies in Ba-added samples and the lower anion vacancies in Nd-added samples were found to be responsible for higher and lower conductivities, respectively.

Polycrystalline ceramics SrBi4-xSmxTi3.9Pr0.1O15 (where x = 0, 0.1, 0.2 and 0.3) were prepared by sol-gel pechini method. The phase formation was confirmed using X-ray diffraction technique and was found to be orthorhombic. Complex impedance spectroscopy (CIS) technique revealed the presence of both grain and grain-boundary effects in the materials. Grain resistance and grain boundary resistance decreases with increasing temperature confirming the NTCR behaviour of the samples. The relaxation times obtained from impedance studies were used to interpret complex impedance nature of the samples. The temperature dependent conductivity obeys the Arrhenius relationship. The impedance studies indicate the non-Debye type of the frequency dispersion for all the samples.

Lead free ferroelectric ceramics in the form of Ba(1-3x)Nd(2x)Ti(1-y)ZryO3 ((where x = 0.025, y = 0 (BT1), 0.025 (BT2), 0.05 (BT3)) were prepared using sol-gel method. The surface morphology and the orientation of grains of the present ceramics were examined using Field Emission Scanning Electron Microscope (FESEM) images. The effect of Nd3+, Zr4+ ions content on the BaTiO3 was studied using Raman and Fourier Transform Infrared (FTIR) spectroscopies. From the Raman analysis the band observed at similar to 838 cm(-1) was attributed due to the presence of Nd3+-barium vacancy pairs. The FTIR studies suggested that the addition of Nd3+ ions in A-site of BaTiO3 (ABO(3)) perovskite create lattice distortion by forming A-site vacancies and Zr4+ ions in B-site of BaTiO3 induce the lattice distortion by forming ZrO6 octahedra in the place of TiO6 octahedra. Dielectric measurements of the samples were done at different frequencies from RT-150 degrees C. Charge transportation phenomenon is explained using DC conductivity, which is found to increase with temperature. (C) 2014 Published by Elsevier B.V.

The pyrochlore oxide of composition YLnTiZrO7 (Ln = La, Nd, Sm, and Eu) was prepared by sol–gel method. All the samples were characterized by powder X-ray diffraction (XRD), Raman, X-ray photoelectron spectroscopy (XPS), diffused reflectance spectroscopy, and impedance spectroscopy. The powder XRD and Raman studies reveal that these samples were crystallized in cubic lattice with pyrochlore structure. The Rietveld analysis of the samples was carried out to obtain the unit cell parameters and reliability factors. The broad Raman bands observed for all the samples are due to cation/anion disorder in the lattice and nanosize. The XPS analysis of the samples shows the characteristic peaks belonging to Y3+, Ln3+ (Ln = La, Nd, Sm, and Eu), Ti4+, and Zr4+. Electrical conductivity of YLaTiZrO7 (YLTZ) and YEuTiZrO7 (YETZ) samples was calculated from the impedance as a function of frequency and temperature. These samples have shown conductivity of the order of 10−5 scm−1 at 500 °C.

Sr Sm-x Bi(4-x) Ti(4-y) Pr-y O-15 (for x = 0, y = 0 and x = 0.1, y = 0, 0.1 and 0.2 and also for x = 0.2, y = 0.1) ceramics were prepared by Sol-gel Pechni method. Single phase of compounds was confirmed by XRD analysis and Lattice parameters were calculated. Microstructure and chemical analysis were performed using SEM and EDS techniques. The effect of addition of Sm3+ and Pr3+ ions on dielectric and polarization properties of Sr Bi-4 Ti-4 O-15 was studied and shift in transition temperature was observed. The dc conductivity of the samples measured as a function of temperature.