Date of Award

2014

Document Type

Thesis

First Advisor

Kebede, Abebe

Abstract

Thin film YBa2Cu3O7-δ (YBCO) samples with added non-superconducting nanodot defects of CeO2 and BaSnO2 are the focus of recent high-temperature superconductor studies. These nanodots allow magnetic flux ( ) to penetrate at these sites of the superconducting lattice, thus creating a magnetic flux vortex state. Examining the structure shows that these quantized magnetic flux vortices arrange themselves in a self-assembled lattice. The nanodots, with non-superconducting properties, serve to present structural properties to restrict motion of these vorticies under a pinning-force and to enhance the critical current density. A formulation of a new model for the system by a variation in the electron pair velocity via the virtual work from the nanodot defects in accordance to the well-known Superconductivity theories is tested. A solution to the expression for the magnetic flux, zero net force and pair velocity will generate a setting for the optimal deposition parameters of number density, growth geometry and mass density of these nanodot structures. With a calculation of pair velocities from a similar work, a comparison is made between experimental and theoretical velocity calculations using growth geometry and chemical potential. This will yield insight into how the current density for a doped high-temperature superconductor will be modified and tuned based on the dynamics and density of the nanodots themselves.

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