Sharmila Mukhopadhyay (Advisor)
Master of Science in Engineering (MSEgr)
This thesis reports the development of a new approach for the fabrication of superconducting thin films. Among the liquid phase methods of fabricating high temperature superconductors having critical current density about 1 MA/cm2, metalorganic deposition using metal trifluoroacetates (TFA-MOD) is the best known method. In this project, detailed spectroscopic and microscopic analysis was performed at every stage of the TFA-MOD process to understand the evolution of crystalline superconducting film. It was observed that the TFA-MOD has some inherent disadvantages such as long process time, evolution of HF gas and results porosity in films. A new liquid phase process was developed to fabricate superconducting YBCO thin films, which has the potential to overcome the above mentioned drawbacks. This process involves using a precursor, which is a colloidal suspension of Y-Ba-Cu-O nanoparticles of size ~ 20 nm. Precursor films were deposited on LaAlO3 by spin coating or dip coating and heat treated in two stage annealing process to obtain final films. Compared to MOD-TFA processed films, the nanoparticle processed films showed lower porosity and can be grown at faster heating rates. The superconducting transition temperature of nanoparticle processed YBCO films to date is ~ 89 K at R=0. Self-field critical current densities (Jc) of 2 MA/cm2 at 77 K have been achieved.
Department or Program
Department of Mechanical and Materials Engineering
Year Degree Awarded
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