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Ca substituted LaFeO3 orthoferrite nanostructure perovskite has been synthesized by gel combustion method using citric acid as a fuel. The structural and optical properties were investigated by various tools. The structural analysis through Rietveld refinement of the XRD data revealed single phase of orthorhombic structure in R-3c space group of the sample without presence of any other impurity phase. Scanning electron microscopy (SEM) image exhibits non-uniform distribution of the nanoparticles in agglomerated form. The purity of the sample and stoichiometric ratio of the elements were established through energy dispersive x-ray spectroscopy (EDS). FTIR spectroscopy measurement predicts the presence of various band relation of the chemical species of Ca with LaFeO3. Optical properties were explored through UV-visible absorption spectroscopy that showed absorption edge at 347 nm and energy band gap was estimated as 3.47eV using Tauc’s relation. [ABSTRACT FROM AUTHOR]

In this paper, we report the synthesis, characterization and photoluminescence properties of Mg-doped TiO2 nanoparticles (NPs). The samples were synthesized by sol-gel method and characterized using the standard analytical techniques such as X-ray diffraction (XRD), Transmission electron microscope (TEM), Energy dispersive X-ray spectroscopy (EDX), UV-visible and photoluminescence spectroscopy. The powder XRD spectra revealed that the synthesized samples are pure and crystalline in nature and showing tetragonal anatase phase of TiO2 NPs. UV-visible spectrum illustrates that an absorption edge shifts toward the visible region. This study may provide a new insight for making the nanomaterials which can be used in photocatalytic applications. [ABSTRACT FROM AUTHOR]

The present work emphasizes the structural, optical and thermal properties of pure TiO2 and TiO2/ZnO nanocomposite. The samples were synthesized by sol-gel method and characterized by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), Ultraviolet-visible spectroscopy and Thermal gravimetric analysis (TGA). The XRD analysis shows that synthesized TiO2 nanoparticles consisted of only anatase phase and also it revealed the presence of both, TiO2 and ZnO phases in TiO2/ZnO nanocomposites. TEM analysis confirmed that the shapes of TiO2/ZnO nanocomposite are spherical (due to TiO2) and nanorods (due to ZnO) and EDS analysis confirmed that synthesized material has no impurity. Thermal gravimetric analysis (TGA) shows the weight loss of the nanoparticles which is found to take place up to 800°C, beyond this temperature no significant weight loss was observed. The band gap of pure TiO2 and TiO2/ZnO nanocomposite have been estimated from absorption peak and found to be 3.14 eV and 2.82 eV respectively. [ABSTRACT FROM AUTHOR]

Perovskite nanocrystalline powder of LaFe0.5Cr0.5O3 was synthesized by sol-gel combustion route and characterized by x-ray diffractometer (XRD), scanning electron microscopy (SEM) equipped with EDS, UV-visible and LCR meter at room temperature Rietveld refinement of the XRD data confirms that the sample is in single phaserhombohedral structure with space group R-3C. SEM micrograph shows clear nanostructure of the sample and EDS ensures the presence of all elements in good stoichiometric. The optical absorption indicates the maximum absorption at 315 nm and optical band gap of 2.94 eV was estimated using Tauc's relation. Dielectric constant (ε') and loss were found to decrease with increase in frequencies. The dielectric behavior was explained on the basis of Maxwell- Wagner's two layer model. [ABSTRACT FROM AUTHOR]

Barium doped lanthanum ferrite (LaFeO3) nanoparticles (NPs) were prepared by gel combustion method and calcinated at 700°C. Microstructural studies were carried by XRD and SEM techniques. The results of structural characterization show the formation of all samples in single phase without any impurity. Optical properties were studied by UV- visible technique. The energy band gap was calculated and obtained 3.01 eV. Dielectric properties characterized by LCR meter and have been observed appreciable changes. The observed behavior of the dielectric properties can be attributed on the basis of Koop's theory based on Maxwell-Wagner two layer models in studied nanoparticles. [ABSTRACT FROM AUTHOR]

We report the structural, morphological and magneto-transport properties of electron doped La0.85Te0.15MnO3(LTMO) thin film grown on (001) LaAlO3 single crystal substrate by pulsed laser deposition (PLD). X-ray diffraction (XRD) results confirm that the film has good crystalline quality, single phase, and c-axis orientation. The atomic force microscopy (AFM) results have revealed that the film consists of grains with the average size in a range of 20-30 nm and root-mean square (rms) roughness of 0.27nm. The resistivity versus temperature measurement exhibits an insulator to metal transition (MIT). We have noticed a huge value of magnetoresistance (~93%) close to MIT in presence of 8T field. X-ray photoemission spectroscopy confirms the electron doping and suggests that Te ions could be in the Te4+ state, while the Mn ions stay in the Mn2+ and Mn3+valence state. [ABSTRACT FROM AUTHOR]

Heavy ion irradiation produces modifications in polymers and adapts their electrical, chemical and optical properties in the form of rearrangement of bonding, cross-linking, chain scission and formation of carbon rich clusters. Modification depends on the ion, its energy and fluence and the polymeric material. In the present work, a study of the dielectric response of pristine and heavy ion irradiated Polyethersulphone (PES) polymer film is carried out. 250 μm thick PES films were irradiated to the fluences of 1012 and 1013 ions/cm2 with Ne6+ ions of 145 MeV energy from Variable Energy Cyclotron Centre, Kolkata On irradiation with heavy ions dielectric constant ([variant_greek_epsilon]′) decreases at higher frequencies and increases with fluences. Variation of loss factor (tan δ) with frequency for pristine and irradiated with Si ions reveals that tan δ increases as the frequency increases. The tanδ also increases with fluence. Tan δ has positive values indicating the dominance of inductive behavior. [ABSTRACT FROM AUTHOR]