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Item Structural, vibrational and surface analysis of Fe3BO6 nanoplates synthesized by combustion method(Elsevier B.V., 2018) Kumari, K.In the present investigation, a simple synthesis method is explored involving a self-combustion of a solid precursor mixture of iron oxide (Fe2O3) and boric acid (H3BO3) using camphor (C10H16O) as fuel in microwave oven in order to form a single phase Fe3BO6 crystallites. An as-prepared ceramic powder in this way after combustion of a precursor, which contained a lot of residual carbon left after the combustion, was reheated at 400 °C to burn it out as oxide in a reaction with air. This is a very simple and fast method to form a phase pure compound from usual metal salts with functional properties. The size and morphology of the Fe3BO6 crystallites has been characterized in terms of X-ray diffraction (XRD) pattern in correlation to the field emission scanning electron microscopy (FESEM) image. A single phase compound Fe3BO6 of an orthorhombic crystal structure with Pnma space group and average crystallites size D = 46 nm is analyzed from the XRD pattern. IR/Raman and X-ray photoelectron spectroscopy (XPS) spectra studied for the Fe3BO6 samples in this investigation elucidate how the density of states of the phonons and valence electrons confine in small crystallites. The XPS bands in Fe3+, B3+ and O2? species and IR/Raman bands in the oxygen polygons confer the results of forming Fe3BO6 with a bonded surface layer. © 2018 Elsevier B.V.Item Sensitivity Study of Nanocrystalline Fe3BO6 Sensor for Methane Gas Detection(Institute of Electrical and Electronics Engineers Inc., 2018) Kumari, K.; Ram, S.The iron borate Fe3BO6 with functionalized properties in a nanostructure is an important material useful for electrodes, gas sensors, and biological probes. In this paper, we studied the X-ray diffraction pattern, field-emission electron microscopy, and methane (CH4) gas sensing properties of synthesized Fe3BO6 nanocrystallites in a shape of nanoplates and nanobars from an iron borate glass 40Fe2O3-60B2O3 by annealing it in microwave for 15 min at 823 and 1023 K, respectively, in air. The temperature dependent sensitivity for CH4 (1000 ppm) illustrates a maximum value of 43% at an operating temperature 525 K for the 1023 K annealed sample. The sensitivity is found to be varied from 9% to 39% when the CH4 gas concentration is increased from 50 to 1000 ppm. Thus, the sample has a reasonably good sensitivity for methane. Furthermore, the sensor exhibits fast response (1 min) and a good recovery time (1.6 min) as compared with other oxide materials. © 2001-2012 IEEE.Item Phase analysis, FTIR/Raman, and optical properties of Fe3BO6 nanocrystallites prepared by glass route at moderate temperature in ambient air(Elsevier B.V., 2018) Kumari, K.In this paper, a facile synthesis method is explored from a supercooled liquid Fe2O3–B2O3 precursor using microwave furnace in order to obtain a single phase Fe3BO6 compound. Study includes X-ray diffraction (XRD), Field emission scanning electron microscope (FESEM), high resolution transmission electron microscopy (HRTEM) images, FTIR/Raman and optical property of sample. The crystal structure and size of the Fe3BO6 crystallites have been characterized in terms of XRD pattern in correlation to the FESEM/HRTEM images. A single phase compound Fe3BO6 of an orthorhombic crystal structure with Pnma space group and average crystallites size D = 49 nm is analyzed from the XRD pattern. IR and Raman bands in the oxygen polygons confer the results of forming Fe3BO6 with a bonded surface layer. UV–visible absorption spectrum over a spectral range 200–800 nm of wavelengths reveals two high-energy bands 222 and 277 nm possibly represent a ligand to metal charge transfer transition while one broad and relatively weak band appears in the visible region at 400 nm ascribed to a ligand field transition 6A1 ? 4T1 of the 3 d5 electrons in the Fe3+ ions occupied. This compound also endures good optical properties in the visible and ultraviolet regions that can be combined to magnetic and other properties useful for developing multifunctional features for possible applications. © 2018