The Optics Laboratory
Group of
Hans Hallen, North Carolina State University Physics Department
Electromigration in YB2C3O7
YBCO is a high temperature superconductor, whose superconducting properties are changed strongly by changes in its oxygen concentration. The oxygen concentration can be altered through electromigration. We study this process with a scanning probe microscope and learn:
• The near-field scanning microscope can be used to induce and detect electromigration on a submicron scale.
• The oxygen content of as-grown YBCO is relatively constant within a grain, but varies between some grains. Those grains emanating above the surface show a reduced oxygen content, indicating diffusion out of these c-axis normal films.
• The electromigration appears to be due to "hot" electron interaction with oxygen atoms for tunnel-current induced motion.
• The grain size limits the extent of electromigration in studies to date.
The details:
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Last updated on October 5, 2000