Nilanjal Misra; Reza Valizadeh; Virendra Kumar
Abstract
The present work reports the design, development and application of a novel Hybrid Physical Chemical Vapour Deposition (HPCVD) technique for depositing MgB2 thin films, with potential superconductivity, directly on three dimensional (3D) surfaces. A novel solenoid magnetron based set up was used for ...
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The present work reports the design, development and application of a novel Hybrid Physical Chemical Vapour Deposition (HPCVD) technique for depositing MgB2 thin films, with potential superconductivity, directly on three dimensional (3D) surfaces. A novel solenoid magnetron based set up was used for depositing MgB2 thin films on 3D surfaces of Cu tube. Mg rod was used as the sputter target and source of Mg while high purity BBr3 was used as a novel boron precursor, which was injected into the system using Argon as carrier gas. The plasma mediated decomposition of BBr3 in presence of H2 gas was followed by chemical reaction between Mg and B atoms to deposit MgB2 film on the substrate. Samples were characterized by SEM, EDX, XRD and SQUID techniques. SEM-EDX confirmed deposition of a homogeneous, pore free and dense MgB2 film, while XRD analysis revealed the film to be polycrystalline and multiphasic rather than being purely c-axis oriented. Superconductivity analysis carried out using SQUID measurements indicated a sharp transition with Tc value of 39 K. From the M-H hysteresis loop, the lower critical field Hc1 and critical current density Jc at 4.2 K were calculated to be 700 Oe and 3.5 x 10 7 A/cm 2 , respectively.
Swarnima Rawat; Nilanjal Misra; Virendra Kumar; Shubhangi Atmaram Shelkar; Narender Kumar Goel; Rakesh Kumar Singhal; Lalit Varshney
Abstract
A robust and reusable Copper Nanoparticles Immobilised Catalytic Reactor (Cu-NICaR) system was fabricated by immobilising Copper Nanoparticles (Cu NPs) onto a radiation functionalized polymer support. Gamma radiation induced simultaneous irradiation grafting process was employed for introducing poly-glycidyl ...
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A robust and reusable Copper Nanoparticles Immobilised Catalytic Reactor (Cu-NICaR) system was fabricated by immobilising Copper Nanoparticles (Cu NPs) onto a radiation functionalized polymer support. Gamma radiation induced simultaneous irradiation grafting process was employed for introducing poly-glycidyl methacrylate (poly(GMA)) chains onto non woven PE-PP matrix. Optimization of the grafting process was carried out by studying the effect of experimental parameters, such as absorbed dose, monomer concentration and solvent polarity on grafting yield. The poly(GMA)-g-PE-PP matrix was used as a functional polymer support for Cu NPs, synthesised under optimized conditions using NaBH4 as reducing agent. Characterization of the samples was carried out by UV-Visible spectrophotometer, Fourier Transform Infrared (FTIR) Spectroscopy, X-ray fluorescence (XRF), Thermogravimetric Analysis (TGA) and Scanning Electron Microscopy (SEM). Catalytic activity of Cu NPs immobilised poly(GMA)-g-PE-PP catalytic system was studied by spectrophotometrically monitoring the catalytic reduction of p-nitrophenol (PNP), using NaBH4 as reducing agent. The Cu NPs-immobilised-poly(GMA)-g-PE-PP was observed to exhibit excellent catalytic activity both in batch process (12 cycles over a period of 30 days) as well as in fixed bed column reactor mode, without significant loss of activity.
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