Environmental Degradation of High Tc Superconductors

Abstract

The recent discovery of high temperature ceramic superconductors sparked off tremendous research efforts all over the world and brought along promises of wide spread use in magnetically levitated trains and ultrafast computers. Prior to 1986, superconductors had to be cooled to liquid helium temperature (4 Kelvin), but recently isolated cases of transition temperatures (Tc) as high as 240 Kelvin have been reported for the newly discovered ceramic compounds. Thin films of high Tc superconductors have promising applications in semiconductor and microelectronics industry since they have high critical current density (Jc)· They also lend themselves to the study of materials parameters responsible for superconduction. However, an inherent problem with high Tc superconducting material is its rapid degradation upon exposure to moisture and water and the subsequent breakdown of superconductivity. In an effort to characterize the degradation pattern of superconductors, a series of controlled tests were run in an in-house fabricated humidity chamber. Bulk material and RF sputter deposited thin films on various substrates were exposed to desired levels of relative humidity for various lengths of time. Comparative studies of the surface and bulk characteristics were performed before and after exposure using i) magnetic susceptibility, ii) Tc measurements, iii) scanning Auger microscopy, iv) x-ray diffraction, v) scanning electron microscopy, vi) energy dispersive x-ray spectroscopy, and vii) optical microscopy. Each one of these techniques provided information on certain aspects of the corrosion phenomena of superconductors and a correlation between the data was used for comprehensive understanding of the degradation process.

Notes

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Graduation Date

1990

Semester

Fall

Advisor

Desai, Vimal H.

Degree

Master of Science (M.S.)

College

College of Engineering

Department

Mechanical Engineering and Aerospace Sciences

Format

PDF

Pages

180 p.

Language

English

Length of Campus-only Access

None

Access Status

Masters Thesis (Open Access)

Identifier

DP0027235

Subjects

Dissertations, Academic -- Engineering; Engineering -- Dissertations, Academic

Accessibility Status

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