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The ability of BaTiO₃ to form solid solutions with different dopants (both iso- and aliovalent) makes it versatile for various applications. In the present study, (Ba,Ca)TiO₃ (BCT) is modified with Bi(MgTi)O₃ (BMT) in search for new lead-free ferroelectric material and improve their properties. For this purpose, BCT acts as a main base material and BMT acts as a modifier to fabricate a multifunctional material. In this study, we report the structural and electrical properties of lead free piezo-ceramics ($1-x$)(Ba${}_{0.8}$Ca${}_{0.2}$)TiO₃–$x$Bi(Mg${}_{0.5}$Ti${}_{0.5}$)O₃ with $x=0.2$, 0.4, 0.5 prepared by solid-state sintering technique. Single perovskite phase with tetragonal structure is obtained for all the compositions, which is reconfirmed by the Raman Spectroscopic study. Dielectric study confirm the temperature stable behavior of the dielectric permittivity values above 300${}^{\circ }$C. The dielectric constant value decreases with increase in BMT doping content. Impedance Spectroscopic study confirms non-Debye type dielectric relaxation in the specimen. The Nyquist plot and conductivity studies show the negative temperature coefficient of resistance behavior (NTCR) of the samples.

The complexation of solid urea with (Co${}^{2+}$), (Cu${}^{2+}$) or (Ni${}^{2+}$) ions has been studied by using dielectric spectroscopy technique over a wide frequency range at different temperatures. Samples' structure were investigated by XRD, FTIR and FT-Raman spectroscopy. FTIR and Raman analysis indicated that the urea coordinates with the metal atoms through the same oxygen–metal bond (O–M). Furthermore, XRD analysis showed that the samples have polycrystalline structure with single phase. The permittivity of complexes was found at much higher values than that of the ligand (pure urea), showing structure dependency. Furthermore, two relaxation peaks were observed in the dielectric loss spectra corresponding to the orientation polarization of urea molecule, and some parts of urea molecule may be NH₂ groups. Both relaxation peaks correspond to thermally activated because they were shifted to higher frequency with the temperature increase. The peak position for the low frequency relaxation peak was observed at the same relaxation time ($\tau =7.6\times 10^{-4}$s), corresponding to the coordination mode through the same O–M bond. Novelty of this work is the successful finding of the relationship between the crystalline phase, coordination mode and the dynamic molecular behavior of solid urea and its complexes using the dielectric spectroscopy technique.

Polycrystalline samples of Bi${}_{1-x}$La_xFeO₃ [$x=0.5$, 0.6, 0.7 and 0.8] were synthesized through high temperature solid state reaction method. The structural studies of the compounds were done using X-ray diffraction technique. Dielectric constant and dielectric loss were studied for various frequencies (100Hz–10⁴Hz) at different temperatures. The temperature-dependent non-Debye type relaxation process was suggested in the materials from the analysis of frequency-dependent electrical data at different temperatures. Temperature dependence of dc and ac conductivity at various frequencies showed negative temperature coefficient of resistance (NTCR) behavior. The frequency dependence of ac conductivity at different temperatures obeyed Jonscher’s universal power law. The temperature dependence of dc and ac conductivity was fitted to Arrhenius equation. The activation energies at different temperature ranges were calculated to know the charge species involved in the conduction process.

This work outlines the characterization of epoxy resin [Bisphenol A-(epichlorhydrin): epoxy] and hardener [$N$(3-dimethylaminopropyl)-1,3-propylenediamine] with various inorganic nano-fillers. Dielectric characterizations of epoxy, hardener, neat epoxy (epoxy + hardener) and nano-epoxy (nano-filler + neat epoxy) composites loaded with 1 wt.% of inorganic nano-fillers (SiO₂, Al₂O₃, TiO₂ and ZnO) were carried out using precision LCR meter, over the frequency range of 1 kHz–2 MHz at a constant temperature of 300.15 K. The structural information of nano-fillers, neat epoxy and nano-epoxy composites was understood by Fourier transform infrared spectroscopy and by XRD. Moreover, hardness and shear strength (shear punch) were also determined in order to gain additional information about the mechanical properties of epoxy composite. Influence of inorganic nano-fillers on the dielectric properties, structural chemistry and mechanical properties of neat epoxy composite is discussed thoroughly in this study.

Solid solution samples of the three-component system (1 − $x$)Pb(Ti${}_{0.5}$Zr${}_{0.5}$)O${}_3-x$CdNb₂O₆ with $x$ = 0.0125–0.0500, $\mathrm{\Delta }$$x$ = 0.0125 were obtained by solid phase synthesis followed by sintering using conventional ceramic technology. The crystal structure, microstructure, electrophysical, and thermophysical properties of these ceramics have been studied. It is shown that all studied solid solutions can be divided into two groups (with $x$ = 0.0125 and with $x>$ 0.0125), characterized by different characteristics of the change in properties with variations in external influences. This is probably due to the transition from a perovskite-type structure with a tetragonal (T) unit cell to inhomogeneous solid solutions consisting of a series of T-phases with similar cell parameters. A conclusion is made about the expediency of using the data obtained in the development of similar materials for devices based on them.

We report a straightforward tool to investigate insulator-metal transition in RCo${\mathrm{\text{O}}}_3$ (R = Pr, and Nd) nanoparticles prepared by a sol–gel technique. Thermogravimetric analysis (TGA) of the as-prepared gel is performed to get the lowest possible calcination temperature of RCo${\mathrm{\text{O}}}_3$ nanoparticles. The Rietveld refinement of the powder X-ray diffraction (XRD) patterns for both samples shows that the samples crystallize in the orthorhombic (Pnma) phase at room temperature. The particle size of the sample is determined by scanning electron microscopy. Ac conductivity of the materials is analyzed in the temperature range from 303 K to 673 K and in the frequency range from 42 Hz to 1.1 MHz. The insulator-to-metal transition of PrCo${\mathrm{\text{O}}}_3$ and NdCo${\mathrm{\text{O}}}_3$ is analyzed by ac impedance spectroscopy. DC resistivity measurement is also done to cross check the insulator-metal transition in RCo${\mathrm{\text{O}}}_3$ system.

Fe-10Ni-7Mn (wt %) martensitic steel is a member of ultrahigh strength steels. This alloy is ductile in the solution annealed condition and shows good age hardenability but it suffers from severe embrittlement after aging. Discontinuous coarsening of grain boundary precipitates was found as the main source of embrittlement. In this paper the effect of cold rolling on the mechanical properties and phase stability of Fe-10Ni-7Mn steel was investigated. Cold rolling for 20%, 60%, and 90% were carried out on a solution annealed material with subsequent aging at 753 K. X- ray diffraction results and transmission electron microscopy (TEM) micrographs showed the presence of austenite in severely cold rolled samples. This austenite is likely formed as a result of deformation, and it seems to originate from a reverse transformation from bcc-martensite to hcp-martensite to austenite, stimulated by increasing the amount of deformation. This transformation improves the mechanical properties in this steel while in as annealed and aged condition it has premature fracture and zero ductility.

Single phase nanocrystalline soft magnetic Mg_0.7-xNi_0.3Zn_xFe₂O₄, ferrites with x = 0.0 − 0.7 were prepared by sol gel auto-combustion method. X-ray diffraction confirms the formation of single phase nano-crystalline cubic spinel ferrites with average grain diameter ranging between 12.9 nm to 23.9 nm. Formation of the ferrite phase without subsequent heat treatment makes sol-gel auto combustion technique especially suitable and economical for the large scale industrial production of the nano-crystalline ferrites for multilayer chip inductor applications (MLCI). Both, lattice parameter and X-ray density shows a linear increase with increasing Zn²⁺ concentration, attributed to the difference in ionic radii and density of Mg and Zn. Increase in Zn content enhances the soft magnetic behavior, exhibiting linear decrease of coercivity from 122.34 Oe to 72.45 Oe, explained by increase of density with Zn addition. The maximum magnetization (M_max)increases up to 0.106 Tesla (for x = 0.4) and. then decreases with increase of Zn content, discussed on the basis of increase of the occupancy of A-site in spinel ferrite by non-magnetic Zn²⁺ ion.

The structural and magnetic measurements have been carried out on La_0.67Sr_0.33Mn_0.93Zn_0.07O₃ (LSMZO) polycrystalline sample. The sample has been prepared through Sol-Gel route. X-ray diffraction (XRD) pattern confirms the single phase nature of the sample with orthorhombic crystal symmetry. Field dependent magnetization shows the hysteresis loop with very low coercive field and the magnetization does not saturate up to the field of 5000 gauss in magnitude.

We investigated the effect of Ni doping on the structural and electrical properties of LaCoO₃. Single phase LaCo_1-xNi_xO₃ (x = 0, 0.1, 0.3, 0.5) were synthesized using solid state reaction method. Space group, lattice constants and atomic positions were determined by Rietveld refinement of powder diffraction data. The unit cell parameters found to increase with Ni doping. Four-probe direct current conductivity measurements were also carried out to investigate transport behavior of compounds. Samples were found to exhibit temperature dependent semiconducting behavior. The drastic improvement of the room-temperature conductivity of doped samples with respect to the pure compound has been observed and explained in terms of decrease in band gap. The transport mechanism in different regions of temperature has been investigated by fitting Arrhenius and variable range hopping (VRH) models.

Nanopowders of Ce_0.8Y_0.2O₂ were prepared by sol-gel via hydrolysis method for different hours. The prepared powders are characterized by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscope (SEM) and analyzed by UV-visible spectroscopy, Photoluminescence (PL) and Energy dispersive X-ray analysis (EDAX). Cubic fluorite structure of the prepared samples was confirmed by powder X-ray diffraction and the grain size of the prepared samples in the range of 12 to 33 nm. The functional groups of the prepared nanopowders are identified by FTIR spectra. The band gap energy obtained from the UV spectra. From the photoluminescence spectra, there is a mirror image relation between absorption and emission spectra. The purity of the prepared samples is confirmed by EDAX measurements.

A single phase polycrystalline hexagonal YMn_0.8Ru_0.2O₃ compound with space group P6₃cm (25-1079) have been synthesized by using solid state reaction method at sintering temperature 1280°C. The detailed low temperature electrical properties were evaluated over a broad range of temperature. The temperature dependence of the dc resistivity at low temperature reveals the semiconducting behavior and favored the variable range hopping conduction model. The obtained experimental data in the temperature range of our study can be described by the equation ρ(T) = ρ₀exp[(T^*/T)^1/4]. The fitting results are used for the calculation of the ;temperature scale T^* ~ 1.05 × 10⁶K and finally the density of state at Fermi level N(E_F) is calculated to be ~ 5.6 × 10¹⁹ eV⁻¹ cm⁻³.

Undoped and Al-doped ZnO (AZO) nanoparticles (NPs) have been successfully synthesized by the simple sol-gel method. The NPs have been characterized by a number of techniques as x-ray diffraction (XRD), UV-visible spectroscopy and scanning electron microscopy (SEM) at room temperature for 0%, 0.5%, 1% and 2% of Al concentration. The structural characteristics were examined using XRD and SEM with EDS. XRD analysis reveals that all samples crystallizes in polycrystalline nature with wurtzite lattice and exhibit no other impurity phase. The average crystallite size decreases with increase in Al concentration. The absorption spectra indicate increase in optical energy gap (E_g) with increase in Al ion doped into the ZnO lattice site.