Masters Theses

Date of Award

5-1993

Degree Type

Thesis

Degree Name

Master of Science

Major

Physics

Major Professor

James R. Thompson

Committee Members

T.A. Callcott, Winston Chen

Abstract

Superconducting thin films were produced by pulsed laser ablation of a YBa2Cu3O7-x pressed pellet target, using a Nd:YAG laser operating at 1060, 532, 355, and 266 nm wavelengths. Various laser fluences from 20 to 0.5 J/cm2 were used in order to study the effect of laser fluence and laser wavelength on film quality. Optimum laser fluence was 3 J/cm3 for all wavelengths, while the best films were produced at shorter wavelengths. Fourier transform infrared (FT-IR) reflectance spectroscopy was used in-situ to observe the film deposition process. Quadrupole mass spectra were obtained independently, with the same laser fluences and wavelengths used previously. Typically, higher fluences produced fewer metal oxide ions, and stoichiometry was not preserved by the ablated positive ions. More Ba+ ions than Y+ or Cu+ ions were observed. No CuO+ ions were detected. SEM photographs revealed that longer wavelengths produced larger particle sizes in the films, and higher fluences produced the same results.

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