The Sr0.95Sm0.0125Dy0.0125□0.025Ti0.90Nb0.10O3?δ/ZrO2 composite was directly prepared through spark plasma sintering. This approach limited the grain growth and facilitated the achievement of a narrow grain size distribution due to fast sintering and ZrO2 effects. Thermal conductivity declined to 1.68 W m−1 K−1, which is the lowest among the reported values for micro-polycrystalline SrTiO3-based structures.

In this study, MgO center dot(Fe2O3)(1-x)(Bi2O3)(x) (x = 0.01, 0.02, 0.04, 0.08) samples were prepared by the conventional ceramic process. Microstructure studies revealed that the samples contain MgFe2O4 grains surrounded by insulating Bi2O3-rich phases. DC electrical resistivity of the samples was increased by Bi2O3 content up to 1.1 M Omega.cm for the sample with x = 0.08. Current density-electric field investigations suggested that the samples with x = 0.01, 0.02 and 0.04 exhibited varistor properties. The sample with x = 0.01 showed excellent varistor properties with a non-linear coefficient of 45 and a threshold electric field value of 160 V/cm. Variation of D.C electrical conductivity versus temperature indicated that the activation

Flame-treatment as a simple, low cost, and highly reliable strategy was applied to effectively enhance the photoelectrochemical (PEC) properties of liquid phase deposited Ti-doped hematite thin films. The samples were heat-treated in three steps: 2 hours at 600 ?C, one minute at 800 ?C, and then 90 seconds in the flame of a paraffin wax candle. The microstructure studies revealed that the granular – morphology of the films depends on Ti doping levels and varies from acicular-like for the undoped and 1% Ti doped to spherical-like for 2–4% Ti, and then to warm-like morphology for 5% Ti-doped samples. The optical band-gap energy values of the samples decreased from 1.94 eV for the undoped to 1.53 eV for the 4% Ti-doped sample. The PEC inve

The main aim of this work was to estimate the dielectric constant of electrospun BaTiO3 nanofibers (BT NFs) using theoretical models. The effect of calcination temperatures on morphology and crystal structure of BT NFs was also investigated by using SEM, TEM, XRD and Raman spectroscopy. The dielectric constant of BT NFs was calculated by applying modified Maxwell Garnett and Yamada models on polymer nanocomposite films comprising stearic acid modified BT NFs in Polyvinylidene difluoride (PVDF) matrix. The results showed that although it was detected low tetragonality (1.0041) at lowest calcination temperature (850 ?C), the better crystallization of BT and high tetragonality could be achieved at a calcination temperature of 1000 ?C and above

In this study zirconia nanoparticles (NPs) were successfully synthesized via the direct current (DC) arc discharge method in water. Formation mechanism of NPs and the effect of arc current on morphological, structural and optical properties of NPs have been studied. The NPs were synthesized at four different currents in the 40–160 A range. SEM observations showed NPs are spherical in shape and their average size decrease from 40 to 22 nm by increasing the current from 40 to 160 A. XRD analysis revealed phase composition of NPs is a mixture of tetragonal and monoclinic for all the samples, and the phase fraction of NPs are arc current dependent in such a way that an increase in the current leads to an increase in the weight percent of the

Iron-doped hydrated nickel molybdate (Fe x Ni 1-x MoO 4. 0.75 H 2 O, x= 0–0.10) nanorods were successfully synthesized via a simple one-pot hydrothermal route. Our investigations showed that hydrated nickel molybdate (HNMO) possesses identical crystal structure to CoMoO4. 0.75 H2O with a triclinic crystal structure and P 1? space group. Electron microscopy studies showed that the HNMO powders consist of single crystalline nanorods with [1 2? 2] growth direction. The effectiveness of iron-doping into the crystalline lattice of the HNMO was demonstrated by powder x-ray diffraction (PXRD), UV–visible spectroscopy and electrochemical impedance spectroscopy (EIS). Upon iron-doping, the band gap energy values reduced from 4.03 eV for the un-d

Heavily Nb-doped strontium titanate (SrTi1-xNbxO3) nanoparticles and SrTi1-xNbxO3/TiO2 nanocomposite powders were synthesized by a sol-gel method. Structural characterization of the obtained powders was performed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and UV–visible spectroscopy. The powders were densified by spark plasma sintering (SPS) method up to 98% of the relative density. Upon composite production, the thermal conductivity of the un-doped samples was effectively decreased for SrTiO3/TiO2 nanocpmposite from 12 to 8 W/m.K. On the other hand, thermal conductivity of the Nb-doped SrTi0.8Nb0.2O3/TiO2 composite was decreased by about 50% down to 3.4 W/m.K in comparison to SrTiO3/TiO2 due to the ph

In this study, MgO.(Fe2O3)1−x(Bi2O3)x (x = 0.01, 0.02, 0.04, 0.08) samples were prepared by the conventional ceramic process. Microstructure studies revealed that the samples contain MgFe2O4 grains surrounded by insulating Bi2O3-rich phases. DC electrical resistivity of the samples was increased by Bi2O3 content up to 1.1 MΩ.cm for the sample with x = 0.08. Current density- electric field investigations suggested that the samples with x = 0.01, 0.02 and 0.04 exhibited varistor properties. The sample with x = 0.01 showed excellent varistor properties with a non-linear coefficient of 45 and a threshold electric field value of 160 V/cm. Variation of D.C electrical conductivity versus temperature indicated that the activa

BaTiO3 (BT) nanotubes (NTs) were synthesized using a co-axial electrospinning process. BT precursor/PVP-ethanol and heavy mineral oil were used as the shell solution and core liquid, respectively. The rheological studies indicated that NTs could be formed by a stable jet at a range of viscosities of the shell solution. Due to the shear thinning behavior of the shell solutions, their actual viscosity values at the time of jet formation will be lower than the viscosity of the core liquid. The morphology of the obtained NTs was strongly influenced by the viscosity of the shell solution. By increasing the concentration of BT precursor, the morphology of the BT NTs was changed from porous to more dense structure. XRD analysis revealed that the c

The coupling between magnetic and electric subsystems in composites of ferromagnetic and ferroelectric phases is a product property that is facilitated by mechanical strain that arises due to magnetostriction and the piezoelectric effect in the constituent phases. Such multiferroic composites are of immense interests for studies on the physics of electromagnetic coupling and for use in a variety of applications. Here, we focus on magneto-electric (ME) coupling in nanocomposites. Particular emphasis is on core-shell particles and coaxial fibers, thin film heterostructures, and planar structures with a variety of mechanical connectivity. A brief review of models that predict strong ME effects in nanostructures is followed by synthesis and cha

Zirconia is one of the important ceramic materials with unique properties such as high melting point, high ionic conductivity, high mechanical properties and low thermal conductivity. Therefore, zirconia is one of the useful materials in refractories, thermal barriers, cutting tools, oxygen sensors electrolytes, catalysis, catalyst supports and solid oxide fuel cells. Recently, direct current (DC) arc discharge is extensively employed to synthesis of metal oxide nanostructures in liquid environments. The aim of this work is the synthesis of colloidal zirconia nanoparticles by DC arc discharge method in water as a medium. Arc discharge was ignited between two pure zirconium electrodes in water. Optical and structural properties of prepared c

Liquid phase deposition (LPD) has been applied for the synthesis of iron phosphate thin films as an example of an effective methodology for the thin film growth of other polyanionic compounds. The prepared films were highly uniform, free of cracks, pure and successfully applied to cover various substrates such as soda-lime glass and stainless steel. The thickness of these films can be easily tailored in the range of 80 nm to 2.7 μm by the deposition time. The chemical equilibria for the hydrolysis of [PF6]− species and the formation of iron phosphate were studied by 19F-NMR and 31P-NMR spectroscopy to get insight into the formation mechanism of iron phosphate thin films. Hydrolysis of [PF6]− occurs very slowly and a longer induction pe