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Full-Text Articles in Engineering

Off-Axis Mgb2 Films Using An In Situ Annealing Pulsed Laser Deposition Method, Yue Zhao, Mihail Ionescu, Josip Horvat, S X. Dou Jan 2005

Off-Axis Mgb2 Films Using An In Situ Annealing Pulsed Laser Deposition Method, Yue Zhao, Mihail Ionescu, Josip Horvat, S X. Dou

Australian Institute for Innovative Materials - Papers

Highly smooth and c-axis oriented superconducting MgB2 thin films were prepared by pulsed laser deposition (PLD) with off-axis geometry. The films were deposited on Al2O3–C substrates perpendicularly aligned to a stoichiometric MgB2 target in a 120 mTorr high purity Ar background gas. An in situ annealing was carried out at 650 °C for 1 min in a 760 Torr Ar atmosphere. Despite the short annealing time, an x-ray θ–2θ scan shows fairly good crystallization, according to the clear c-axis oriented peaks for the films. Both atomic force microscopy and the x-ray diffraction …


The Effects Of Electrode Geometry On Current Pulse Caused By Electrical Discharge Over An Ultra-Fast Laser Filament, Matthew Bubelnik Jan 2005

The Effects Of Electrode Geometry On Current Pulse Caused By Electrical Discharge Over An Ultra-Fast Laser Filament, Matthew Bubelnik

Electronic Theses and Dissertations

The time-resolved electrical conductivity of a short-pulse generated plasma filament in air was studied. Close-coupled metal electrodes were used to discharge the stored energy of a high-voltage capacitor and the resulting microsecond-scale electrical discharge was measured using fast current sensors. Significant differences in the time dependence of the current were seen with the two electrode geometries used. Using sharp-tipped electrodes additional peaks in the time-resolved conductivity were seen, relative to the single peak seen with spherical electrodes. We attribute these additional features to secondary electron collisional ionization brought about by field enhancement at the tips. Additional discrepancies in the currents …