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In this paper, a systematic investigation has been done to study the effect of variation in annealing temperature on magnetic and optical properties of Mn-doped SnO2. Coprecipitation technique has been used to synthesize Sn1-xMnxO2 samples with low Mn concentration (2%). Pristine SnO2 is sintered at 350 °C. Mn-doped SnO2 samples are sintered at 350, 450, 550 and 650 °C. The structures of tetragonal rutile of SnO2 and Mndoped SnO2 have been confirmed by the XRD pattern. Typical ferromagnetic ordering has been observed for Mn-doped SnO2 samples annealed at different temperatures. However, on increasing the annealing temperature saturation magnetization as well as the coercive field decreases, indicating a crucial phase transformation from ferromagnetism to paramagnetism. UV-Vis spectroscopy shows increase in absorbance and a slight shift in the absorption edge with Mn-doping at increasing annealing temperature indicating shifting of absorption peak towards higher wavelength. Tauc's plot has been used to find the optical band gap (Eg). [ABSTRACT FROM AUTHOR]

Au-C 60 nanocomposite thin film (Au nanoparticles embedded in fullerene C 60 matrix) is synthesized by thermal co-evaporation method and subsequent thermal annealing from 150 °C to 300 °C. A very small concentration of Au (∼2 at.%) is chosen in order to minimize the deterioration of the physical and chemical properties of fullerene C 60 due to the presence of metal. Spherical shaped Au nanoparticles with a diameter of 2.1 ± 0.04 nm are clearly seen in the TEM images of the nanocomposite annealed at 200 °C. A broad surface plasmon resonance peak at ∼581 nm emerges in UV-visible absorption spectrum due to the evolution of Au nanoparticles at a temperature of 250 °C, which is further blue shifted at ∼554 nm with a narrower FWHM at 300 °C. The presence of Au nanoparticles is also confirmed by X-ray diffraction with Au (111) and Au (200) fcc reflections. Thermally induced transformations of fullerene C 60 matrix at high temperatures is studied by Raman spectroscopy on pure fullerene C 60 films (without metal). The blue shift of LSPR at a temperature of 300 °C is ascribed to the transformation of fullerene C 60 matrix into amorphous carbon and is explained in terms of Mie theory. TEM results show the growth of Au nanoparticles in fullerene matrix at higher temperatures due to the enhanced diffusion of Au atoms and Ostwald ripening. [ABSTRACT FROM AUTHOR]

The title compound, 2-(thiophen-2-yl)-1-(5-thioxo-4,5-dihydro-1,3,4-oxadiazol-2-yl)ethenyl] benzamide: N, N-dimethylformamide (1: 1), (CHNOS · CHNO), was synthesized, and its structure was established by spectral analysis and X-ray diffraction studies. The compound crystallizes in the monoclinic space group P2/ n with a = 10.8714(7), b = 9.0497(5), c = 19.8347(13) Å, β = 91.093(5)°, Z = 4. The crystal structure is stabilized by N-H···S, C-H···O and N-H···O hydrogen bonds. The π···π interactions are also observed between the rings. [ABSTRACT FROM AUTHOR]

We demonstrate chemical doping of a topological insulator Bi2Se3 using ion implantation. Ion beam-induced structural damage was characterized using grazing incidence X-ray diffraction and transmission electron microscopy. Ion damage was reversed using a simple thermal annealing step. Carrier-type conversion was achieved using ion implantation followed by an activation anneal in Bi2Se3 thin films. These two sets of experiments establish the feasibility of ion implantation for chemical modification of Bi2Se3, a prototypical topological insulator. Ion implantation can, in principle, be used for any topological insulator. The direct implantation of dopants should allow better control over carrier concentrations for the purposes of achieving low bulk conductivity. Ion implantation also enables the fabrication of inhomogeneously doped structures, which in turn should make possible new types of device designs. [ABSTRACT FROM AUTHOR]

Hydroxyapatite, Ca10(PO4)6(OH)2 or HAP, is an important bio-material, which is having application in bone implants and dentistry. In the present study, zinc doped nano-hydroxyapatite (Zn-HAP) was synthesized via chemical precipitation route using surfactant mediated approach. The doping of zinc was confirmed by EDAX. The powder X-ray diffraction (XRD) pattern revealed the typical hydroxyapatite pattern with broadening and extra peaks were observed for higher concentration. The average crystallite size was calculated by applying the Scherrer's formula to powder XRD pattern and was found in the range of 16 to 33 nm. The morphology of synthesized nano-particles was also confirmed using TEM. FTIR spectroscopy was used to confirm the presence of various bonds. The dielectric study was carried out at room temperature within the frequency range from 102 Hz to 107 Hz and the variations of dielectric constant with frequency of applied field as well as with the concentration of zinc were studied. It was found that as the concentration of zinc increased the dielectric constant increased. The variations of dielectric loss and a.c. conductivity with frequency of applied field were studied. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

X-ray diffraction (XRD) analysis has been carried out on Se19Te81-xZnx (x = 0, 3, 6, 9) samples and their diffractograms are analyzed to obtain information about various crystallographic aspects. XRD traces of all samples are taken at room temperature which shows almost similar trends. These traces confirm the formation of alloys of Se19Te81-xZnx. The presence of sharp structural peaks in these XRD patterns confirmed the polycrystalline nature of the material. In all the samples the average particle size of the alloy is found to be 4.4778 μm and mean density is found to be 120.73 g/cc. [ABSTRACT FROM AUTHOR]

Copper and cobalt complexes derived from 3-(N-phenyl)-thiourea-pentanone-2 were characterized by elemental, XRD, FTIR, UV-Vis, SEM and 1H NMR spectroanalytical studies. The X-ray diffraction studies indicate that 3-(N-phenyl)-thiourea-pentanone-2 and complexes with copper and cobalt are crystalline in nature with simple cubic lattice structure. IR spectroscopic data were used to assign characteristic vibrational frequencies of groups present in these compounds. Scanning electron micrograms were used to assign morphology and particle size. [ABSTRACT FROM AUTHOR]

Abstract: New tertiary chloro-bis(1,2-N,N-dimethylaminomethylferrocenyl)stibine (1) and tris-(1,2-N,N-dimethylaminomethylferrocenyl)stibine ligand (2) containing CH2NMe2 pendenant arm at the ortho-position have been synthesized. Stibine (2) reacts with PtCl4 2− and hetero trimetallic cis-PtCl2L (3) complex is obtained, where stibine (2) acts as a bidentate ligand. All these compounds were characterized by various physicochemical methods and their molecular structures were determined by X-ray diffraction analyses. It is to be noted that tris(1,2-aminomethylferrocenyl)stibine represents the first example of a structurally characterized ferrocenyl pnictogen where three 1,2-disubstituted ferrocenyl groups are attached to the central antimony atom and phosphorus analogue of the stibine is missing in the literature. Stibine (1) shows a hypervalent Sb–N interaction while stibine (2) does not show this interaction in solid state. [Copyright &y& Elsevier]

The consequences of swift heavy ion (SHI) irradiation (Li3 + , 50 MeV, fluence = 5 × 1013 ions/cm2) on the structural and microscopic magnetic properties of Y3 + -substituted yttrium iron garnet (Y3 + x Fe5 − x O12, x = 0.0, 0.2 and 0.4) have been studied at 300 K. It is found that an additional YFeO3-phase observed along with bcc garnet phase, is completely removed for x = 0.2 composition while its percentage formation considerably reduces for x = 0.4 composition after irradiation. Similar effect has been observed for specimens sintered at 1,500°C. The SHI-induced ion beam mixing has been revealed through X-ray diffraction and Mössbauer spectroscopy. [ABSTRACT FROM AUTHOR]

Abstract: In the present study, barium hexaferrite powders were prepared by ordinarily mixing and by high energy ball-milling stoichiometric amounts of the BaCO3 and Fe2O3 precursors, followed by heat treatments carried out in the 900–1100°C range of temperature. The structural and magnetic properties of the resulting powders were analyzed by differential thermal analysis, X-ray diffraction, scanning electron microscopy, Mössbauer spectroscopy and magnetization measurements. The milled powder showed a lower decomposition temperature and higher surface area than the ordinarily mixed powder. Formation of the BaFe2O4 intermediate phase was observed in conventionally prepared hexaferrites. Diversely, the mechanical process before annealing allowed for the hexaferrite formation at much lower temperatures but without formation of intermediate phases. The hyperfine parameters showed to be independent of the processing method. Higher saturation magnetization, and coercivity were observed in the barium hexaferrites prepared by high energy ball milling. [Copyright &y& Elsevier]

Raw rice cultivars, Basmati-370 (Fine) and Jaya (Coarse) exhibited essentially A-type diffraction patterns, however coarse variety showed somewhat more crystalline than fine one. Blending of Jaya rice flour with different grams (bengal, black, and green gram) did not cause any change in d-spacings and hence blends were characterized for A-type patterns. Extrusion cooking disorganized the crystalline structure of starch component of different blends and resulted in the conversion of A-type pattern to V-hydrate (less crystalline) pattern. The presence of V-amylose structure in extruded blends indicated complexing of amylose with fatty acids of legumes during extrusion cooking. [ABSTRACT FROM AUTHOR]

Background: a humidity sensor is used to sense and measure the relative humidity of air. A new composite system has been fabricated using environmental pollutants such as carbon black and low-cost zinc oxide, and it acts as a humidity sensor. Residual life of the sensor is calculated and an expert system is modelled. For properties and nature confirmation, characterization is performed, and a sensing material is fabricated. Methodology: characterization is performed on the fabricated material. Complex impedance spectroscopy (CIS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) are all used to confirm the surface roughness, its composite nature as well as the morphology of the composite. The residual lifetime of the fabricated humidity sensor is calculated by means of accelerated life testing. An intelligent model is designed using artificial intelligence techniques, including the artificial neural network (ANN), fuzzy inference system (FIS) and adaptive neuro-fuzzy inference system (ANFIS). Results: maximum conductivity obtained is 6.4£10-3 S/cm when zinc oxide is doped with 80% of carbon black. Conclusion: the solid composite obtained possesses good humidity-sensing capability in the range of 30-95%. ANFIS exhibits the maximum prediction accuracy, with an error rate of just 1.1%. [ABSTRACT FROM AUTHOR]

In the present study, iron-containing pyrochlores of the A2FeBO7 type (where A = Y, Gd, Eu and Dy; B = Sb and Nb) were synthesized by solid-state reaction of precursor oxides. The compounds were structurally and magnetically characterized by X-ray diffraction, Mössbauer spectroscopy and magnetic measurements. The results revealed that the crystallographic structures and magnetic properties depend, basically, on the type of B atoms. [ABSTRACT FROM AUTHOR]

Lattice constant of Bi2Se3 and Sb2Te3 crystals is determined by x-ray powder diffraction measurement in a wide temperature range. Linear thermal expansion coefficients (α) of the crystals are extracted, and considerable anisotropy between α|| and α⊥ is observed. The low temperature values of α can be fit well by the Debye model, while an anomalous behavior at above 150 K is evidenced and explained. Grüneisen parameters of the materials are also estimated at room temperature. [ABSTRACT FROM AUTHOR]