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Spray pyrolysis processing of yttrium-barium-copper-oxide and bismuth-strontium-calcium-copper-oxide superconducting thin filmsBania, William Roger, 1964- January 1989 (has links)
The purpose of this investigation was to explore the processing parameters involved in the production of thin film superconductors by spray pyrolysis processing (SPP). The present study is an attempt to optimize the many parameters in SPP. The specific parameters studied were substrate temperature, carrier gas flow rate, substrate materials, solution stoichiometry, spray rate, concentration, starting materials, and substrate to nozzle distance. The effect of these parameters on film stoichiometry and the anticipated superconducting behavior were investigated at some length. Films were routinely produced in a spray chamber designed as a part of this research. Films were analyzed by Rutherford Backscattering Spectroscopy, X-Ray Diffraction, Scanning Electron Microscopy, and Meissner effect measurements.
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Investigation into the synthesis and carbon doping of MgB₂for possible bulk superconducting fault current limiters application.Archer, Jonathan Celvin. January 2012 (has links)
Magnesium Diboride (MgB₂) bulk superconductor has been manufactured for use in
superconducting fault current limiters (SFCLs) via in situ reaction. SFCLs have proven to be a
viable means for limiting surge currents on power lines by dissipating fault energy as the
superconductor quenches. As the current limiting behaviour is determined by the normal resistance
(Rn), research has been conducted to evaluate an effective means to increase Rn for bulk
superconducting MgB₂. Other researchers have previously looked into the improvement and
optimisation of the critical current, Jc, by carbon doping and other flux pinning techniques. Carbon
doping has been confirmed as a means to increase Rn, and was implemented by chemical vapour
deposition (CVD) at 600 ºC in a tubular furnace apparatus. Intragranular doping was achieved by
CVD on the boron precursor powder. In situ manufacturing of MgB₂ bulk was performed using the
reactive liquid magnesium infiltration technique. Carbon doping provided an adequate increase in
Rn, for a small decrease in the critical temperature, Tc. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2012.
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