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# Fabrication and measurement of superconducting nanowires

Walliman, Dominic Christoph (2010)
Ph.D. thesis, University of Birmingham.

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## Abstract

An investigation was made into techniques that could be employed to produce sub-100nm wide superconducting nanowires. Nanowires of niobium and Y Ba$$_2$$Cu$$_3$$O$$_{7-δ}$$ (YBCO) were fabricated in thin films using focused gallium ion beam milling (FIB) to a range of widths (100nm-300nm). A procedure was developed to controllably reduce the wire widths using argon ion beam milling. Milling niobium wires under rotation at 75 degrees to the normal produced wires with width and thickness ∼70nm. The nanowires were cryogenically cooled to 4K and the resistance versus temperature characteristics measured. Nb and YBCO wires exhibited a broadening of the superconducting transition, which fitted reasonably with the theory of thermally activated phase slips. Further analysis of the voltage versus current characteristics of the wires showed behaviour not in agreement with the established theory. Various possible explanations were considered for this, with the conclusion that damage to the wires caused by implantation of gallium was

Type of Work: Ph.D. thesis. Muirhead, Christopher M Colleges (2008 onwards) > College of Engineering & Physical Sciences School of Physics and Astronomy TK Electrical engineering. Electronics Nuclear engineeringQC Physics University of Birmingham 1162
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