Advanced Materials Research Vol. 1169

Abstract: In the present work, we have synthesized x [Co_0.9Ni_0.1Fe₂O₄]-(1-x) [0.5Ba_0.7Ca_0.3TiO₃-0.5BaZr_0.2Ti_0.8O₃], x = 0.3, 0.4 & 0.5 multiferroic composite by hydroxide co-precipitation method. The structural and morphological analysis of the composite was carried out by using X-ray diffraction and Scanning Electron Microscopy. The XRD spectra confirm the perovskite phase and spinel phase. Dielectric properties of the composite were studied using Impedance analyzer. The variation of dielectric constant and loss of tangent (Quality factor) in the frequency range of 100 Hz to 1 MHz were investigated. Magnetocapacitance were measured for magnetic field up to 1 Tesla, which increases with increase in magnetic field. Dielectric constant possesses contribution due to magnetic field dependent interfacial polarization and variation due to induced stress which can be explained on the observed MD effect. Saturation magnetization of composites increases with increase in CNFO content.

Abstract: Complex permittivity spectra of various concentrations (0.0 → 1.0) of n-Butanol and its mixtures with Valeronitrile were obtained in the radio and microwave frequency range (0.2 GHz to 20 GHz) using Vector network analyzer (VNA). Complex permittivity data points were fitted into Havriliak-Negami Model. CNLS fitting using LEVMW software used to obtain dielectric parameters. Excess static dielectric constant and excess inverse relaxation time for the binary mixtures were calculated and fitted in Redlich-Kister polynomial to derive the binary coefficients and standard deviations. Variation of these parameters were discussed in terms molecular interaction between molecular species.

Abstract: Here, we report the synthesis, characterizations and magnetic properties of Ce-Al co-doped nickel ferrite. The samples of pure nickel ferrite ( NiFe₂O₄ ) and Ce-Al doped nickel ferrite (NiFe_1.96Ce_0.02Al_0.02O₄ ) were prepared in nanocrystalline form using sol-gel auto combustion method. X-ray diffraction technique was employed to know the phase purity and for the determination of structural properties. Examination of XRD pattern shows the presence of those reflections which belongs to cubic spinel structure indicating the formation of single phase cubic spinel structure. The lattice constant, X-ray density and other structural parameters were determined from the XRD data and the influence of Al-Ce doping is studied. It is observed from structural studies that the lattice constant and other structural parameters increased. as compared to pure nickel ferrite. The magnetic properties were studied at room temperature using pulsed field hysteresis loop technique. The M-H plot show typical ferrimagnetic behaviour from which the values of saturation magnetization, coercivity and remanence magnetization were obtained. The magnetic data suggests that, Al-Ce co-doping strongly influences the magnetic properties also. The doping of Ce-Al in nickel ferrite leads to canted spin structure. The observed magnetic bahaviour of Ce-Al doped nickel ferrite is explained on the basis of Neel’s and Yafet-Kittel model.

Abstract: Zinc oxide (ZnO) thin films are synthesized by using modified successive ionic layer adsorption and reaction techniques (SILAR) on glass substrate at room temperature. These as deposited thin films are characterized for structural, compositional, surface morphology and optical characterizations using X-ray diffraction (XRD), energy dispersive X-ray absorption spectra analysis (EDAX), atomic force microscopy (AFM) and Uv-vis absorption spectroscopy. From XRD pattern; the low intensity peaks indicate that the films consist coarsely fine grains and/or amorphous in nature. The diffraction peaks observed at 2θ = 31.71 ̊, 36.27 ̊and 56.29 ̊ are attributed to (100), (101) and (110) planes having hexagonal phase while EDAX shows elemental traces for Zn and O. Surface morphology observed from the AFM corresponds granular shape evenly distributed over substrate surface.

Abstract: The single crystals of MSe₂ (M = Nb, Mo, Ta and W) were grown through vapour phase by screw dislocation mechanism. The development of stresses by variation in high temperature of the dual zones involved, resulting into slip lines and vapour inclusion, might possibly lead to generation of favourable screw dislocation sites. The morphology of as grown crystals has been studied by TEM. From this analysis, the general rule that nanoparticles of compounds, crystallizing in layered structures tend to form closed shapes. The formation of closed shapes reduces the number of dangling bonds on the periphery of the layers.

Abstract: Highly conducting Ag₂S thin films were synthesized on FTO substrates at room temperature using simple and versatile successive ionic layer adsorption and reaction (SILAR) method. SILAR method was used to deposit silver sulfide (Ag₂S) thin films of about 299 nm thickness, under optimized deposition conditions viz. SILAR cycles (50), immersion time (25 s), and rinsing time (15 s). X-ray diffraction (XRD) study indicates the formation of polycrystalline Ag₂S with preferential orientation along (1 0 0) plane. Field emmission scanning electron microscopy (FESEM) will be used for study of the surface morphology of materials synthesized in thin film form. FESEM images showed that the deposited Ag₂S thin films were homogenous, without cracks and with dense surface morphology covering entire substrate surface area. Compositional analysis showed that the Ag₂S thin film becomes sulphur deficient and silver richer. Electrical studies showed that the deposited Ag₂S films are highly conducting and can be used in photosensor and/or optoelectronic devices.

Abstract: The present article deals with synthesis of CdS thin films using cost effective chemical bath deposition method and study effect of annealing over the structural properties using X-ray diffraction pattern (XRD). The XRD pattern revealed shift in peak position and variation in intensity upon annealing at different temperatures; this may be attributed to annealing assisted modifications in composition of the thin films. The as deposited CdS thin films represents peaks corresponding to (002), (101), (111) and (110) which in case of annealed samples at 200 and 400oC get modified and slightly shifted with rising some new peaks corresponding to (200) and (001) respectively. The crystallite size of the CdS thin films upon annealing is observed to be increased this may be co-related to the fact energy induced grain growth.

Abstract: In the present work, pure copper ferrite (CuFe₂O₄) thin film has been grown on clean glass substrate by using the spray pyrolysis deposition technique. All the necessary parameters were optimized before the deposition. The deposited thin film was annealed at 500°C for 4 h and then cooled to room temperature. X-ray diffraction (XRD) technique was used to study the phase purity and crystal structure of the sample formed on the thin film. The analysis of the X-ray diffraction pattern reveals the formation of a single-phase cubic spinel structure. The lattice constant and other structural parameters calculated from XRD data are in good agreement with the reported data.

Abstract: Nickel ferrite NiFe₂O₄ nanoparticles were synthesized through sol-gel auto combustion method using dextrose as a fuel. The prepared nanoparticles were investigated for their structural, optical and magnetic characterization. X-ray diffraction (XRD) revealed the development of single-phase cubic spinel with crystallite size of 14 nm. The optical study showed that the compound has an optical band gap 2.26 eV. The magnetic properties were investigated through M-H hysteresis curve. The photocatalytic activity of nickel ferrite was studied based on the degradation of methylene blue (MB) as a model compound, where the results showed that prepared nanoparticles possess a good photocatalytic activity.