Trace element analysis of fly ash samples by EDXRF technique

Trace element analysis of some fly ash samples and soil samples have been carried out by Energy Dispersive X-Ray Fluorescence technique. Fourteen elements namely K, Ca, Ti, V, Cr, Mn, Fe, Co, Cu, Zn, Se, Rb, Sr and Pb have been quantified in the fly ash samples by this technique. It was found that there is no huge concentration difference between the fly ash and soil samples as a result of which fly ash can be used as soil manure without any adverse impact on the plants.Trace element analysis of fly ash samples by EDXRF technique T R Rautray1*, B Behera1, T Badapanda1, V Vijayan2 and S Panigrahi1 1Department of Physics, National Institute of Technology, Rourkela-769 008, Orissa, India 2Department of Physics, Valliammai Engineering College, SRM Nagar, Chennai-603 203, Tamil Nadu, India E-mail : [email protected] of Physics, National Institute of Technology, Rourkela-769 008, Orissa, India 2Department of Physics, Valliammai Engineering College, SRM Nagar, Chennai-603 203, Tamil Nadu, Indi

Synthesis, Electrical Conductivity, and Dielectric Behaviour of Polyaniline Doped with H2SO4; HCl and (HCl + NaNO2) Mixture

Acid doped Polyaniline (PANI) due to their increased electrical conductivity, are considered to be the most promising conducting filler materials. Hence, the present study, reports the synthesis of the PANI followed by acid doping, electrical conductivity and dielectric properties measurements of H2SO4; HCl and (Conc. HCl + NaNO2mixture) doped PANI. In order to know the effect of acetone washing on the electrical properties of acid doped PANI samples, the electrical properties of the non-acetone washed acid doped PANI samples are compared with that of their acetone washed counterparts. The PANI salt was prepared by conventional route using aniline hydrochloride and ammonium persulphate as an oxidant. PANI salt was subjected to 0.5M NaOH to form PANI base, which was further doped separately with H2SO4; HCl and (Conc. HCl + NaNO2mixture) respectively followed by acetone washing. A comparative electrical conductivity study between the acetone washed and unwashed PANI salt and H2SO4, HCl and Conc. HCl + NaNO2 mixture doped PANI were characterized by dielectric and impedance study

Photoluminescence property of Ba('Zr IND.0.25''Ti IND.0.75)'O IND.3' powders prepared by solid state reaction and polymeric precursor method

Ba(Zr0.25Ti0.75)O3 (BZT) powders were synthesized by the polymeric precursor method (PPM) at different temperatures (400, 500 and 700 °C) for 2 h and by the solid state reaction (SSR) at 1350 °C for 4 h. These powders were analyzed by X-ray diffraction (XRD), ultraviolet–visible (UV–vis) absorption spectroscopy and photoluminescence (PL) measurements. XRD patterns indicated that the crystalline BZT powders prepared by both methods present a cubic structure. The different optical band gap values were observed from the UV–vis spectra, suggesting the presence of intermediary energy levels (shallow and deep holes) within the band gap. When excited with 350 nm wavelength at room temperature, the BZT powders obtained by SSR exhibited only one broad PL band with a maximum at around 467 nm (blue emission). On the other hand, it was noted the presence of two broad bands when BZT powders were prepared by the PPM, where the correspondent positions are influenced by the heat treatment temperatures. Finally, a model was proposed in order to explain the origin of the PL property in these powders.CAPESCNPQFAPES

Structure and optical properties of [Ba(1-x)Y(2x/3)](Zr0.25Ti0.75)O3 powders

[Ba1–xY2x/3](Zr0.25Ti0.75)O3 powders with different yttrium concentrations (x = 0, 0.025 and 0.05) were prepared by solid state reaction. These powders were analyzed by X-ray diffraction (XRD), Fourier transform Raman scattering (FT-RS), Fourier transform infrared (FT-IR) and X-ray absorption near-edge (XANES) spectroscopies. The optical properties were investigated by means of ultraviolet-visible (UV-vis) absorption spectroscopy and photoluminescence (PL) measurements. Even with the addition of yttrium, the XRD patterns revealed that all powders crystallize in a perovskite-type cubic structure. FT-RS and FT-IR spectra indicated that the presence of [YO6] clusters is able to change the interaction forces between the O-Ti-O and O-Zr-O bonds. XANES spectra were used to obtain information on the off-center Ti displacements or distortion effects on the [TiO6] clusters. The different optical band gap values estimated from UV-vis spectra suggested the existence of intermediary energy levels (shallow or deep holes) within the band gap. The PL measurements carried out with a 350 nm wavelength at room temperature showed that all powders present typical broad band emissions in the blue region.FAPESP (09/50303-4)CNPqCAPESLNLS (D04B - XAFS1 - 8823

Theoretical description of ABO3 relaxor ferroelectric : A review

Significant similarities exist between spin glasses and relaxor ferroelectric. Because of the wealth of available knowledge both in experimental and theoretical aspects in the former, attempt has been made by many workers to deal the relaxor behavior in analogy with the spin glasses. However, the nature of diffused phase transition in relaxor ferroelectric remains controversial. To overcome this difficulty, many workers extended the above model to a new type of dipolar glasses, namely spherical vector glasses in which order parameter field is described as a continuous vector field of variable length instead of fixed length as proposed earlier. The present review is aimed to focus on all the models.Theoretical description of ABO3 relaxor ferroelectric : A review M R Panigrahi, T Badapanda and S Panigrahi* Department of Physics, National Institute of Technology, Rourkela-769 008, Orissa, India E-mail : [email protected] of Physics, National Institute of Technology, Rourkela-769 008, Orissa, Indi

Dielectric study of spin coated nano-thick BaZrxTi₁₋xO₃ film

749-753Barium zirconium titanate thin films are attractive candidates for dynamic random access memories and tunable microwave devices. Barium zirconate titanate Ba(ZrxTi₁₋x) O₃ (BZT, y = 0.0, 0.2, 0.4) ceramics have been prepared by a sol-gel process. X-ray diffraction studies confirmed that the films of BZT are in crystalline form and of single phase. The SEM study shows that the films of homogeneous microstructure and Zr content strongly influence the grain size of the film. The grain size decreased and the microstructure became dense when Zr was substituted for Ti. The room temperature dielectric study shows that the permittivity as well as dielectric loss tangent decreases with increase in Zr content in the film. The ac conductivity was evaluated from dielectric data and was found to be decrease with increase in Zr concentration