[CCoE Notice] Master's Thesis Defense

[Khator, Suresh]

MASTER'S THESIS DEFENSE
FABRICATION OF NANOWIRES BY CHEMICAL VAPOR DEPOSITION FOR PINNING IN SUPERCONDUCTING FILMS
Xin Tao

November 18th, 9:30 am, Chemical Engineering conference room, S234
Committee Members: Venkat Selvamanickam, Professor, Mechanical Engineering, Li Sun, Associate Professor, Mechanical Engineering, Jiming Bao, Assistant Professor, Electrical and Computer Engineering

ZnO and SnO2 nanowires have been pre-synthesized on the surface of buffer layers prior to deposition of superconducting thin films in order to pin magnetic flux lines. After deposition of REBCO superconducting film, samples embedded with ZnO nanowires showed low critical current and depressed transition temperature, indicating the incompatibility between ZnO and REBCO. On the other hand, the out-of-plane SnO2 nanowires synthesized in single-step VLS method were all found to be accompanied by in-plane wire-like nanostructures, which may impede the epitaxial growth of superconducting film. Two methods, which involve two-step growth and ion-bombardment of SnO2 nanowires, have been explored to remove the in-plane structures. After deposition of superconducting film, decent critical current (Ic) over 200A and non-suppressed transition temperature were obtained in ion-bombarded SnO2 nanowire samples. High H ║ab to H ║c ratio and lower rate of reduction of Ic in higher field indicated possible flux pinning from SnO2 nanowires.
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