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Degree

Master of Science in Engineering (MSEgr), Wright State University, Materials Science and Engineering, 2007.

Abstract

Vemulakonda, Padma Prasuna. M.S.Egr., Department of Mechanical and Materials Science Engineering, 2007. Comparative Characterization of Superconducting Thin Films Fabricated by Different Techniques. The goal of this thesis is to compare the chemical and compositional profiles, grain structure and critical current densities of superconducting Yttrium Barium Copper Oxide(Y1Ba2Cu3O7-x or YBCO) layers grown by different competing techniques on a variety of substrates and buffer layers. The idea is to check if there can be variation of cationic ratios, impurities, possible diffusion of substrate/buffer layer atoms into the YBCO for different processing methods and microstructures. Pulsed Laser Deposition (PLD), Metal Organic Deposition (MOD) and Metal Organic Chemical Vapor Deposition (MOCVD) films on Ion Beam Assisted Deposited (IBAD)-textured buffer layers and, Rolling Assisted Biaxial textured substrate (RABiTS) combinations have been compared. X-ray Photoelectron Spectroscopy (XPS) has been used in conjunction with ion beam sputtering as well as gentle chemical etching to obtain composition and chemistry information at different depths into the film. Correlation with Secondary Ion Mass Spectroscopy (SIMS) has been obtained as needed. Top view as well as cross section Scanning Electron Microscope (SEM) was performed for microstructure analysis. Using the gentle chemical etching method, depth profiling of composition and microstructure of the films has been achieved. It is seen that variations in microstructure occur along the depth of the superconducting layer even when the composition is uniform. The density and the micro-structural uniformity vary significantly from one deposition technique to other. The durability and stability of these films, microstructure, depth profiling have been compared and will be presented. This thesis provides important information on variations of the YBCO films from one deposition technique to another.

Subject Headings

Engineering, Materials Science

Keywords

YBCO; PLD; MOCVD; MOD; IBAD; YSZ; Zr diffusion; Depth profiling; RABiTS; Bromine etching; Chemical profiling; XPS; Depth profiling of microstructure

Advisor

Sharmila M. Mukhopadhyay

Pages

84p.

Document number: wright1176576035
Permalink: http://rave.ohiolink.edu/etdc/view?acc_num=wright1176576035

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