Investigation of single Abrikosov vortex pinning in superconducting Josephson junctions using artificially induced pinning sites

Thumbnail Image
Date
1999
Authors
Breitwisch, Matthew
Major Professor
Advisor
D. K. Finnemore
Committee Member
Journal Title
Journal ISSN
Volume Title
Publisher
Altmetrics
Authors
Research Projects
Organizational Units
Organizational Unit
Physics and Astronomy
Physics and astronomy are basic natural sciences which attempt to describe and provide an understanding of both our world and our universe. Physics serves as the underpinning of many different disciplines including the other natural sciences and technological areas.
Journal Issue
Is Version Of
Versions
Series
Department
Physics and Astronomy
Abstract

Cross-strip superconductor-normal-insulator-superconductor Josephson junctions have been fabricated in order to study the pinning of a single Abrikosov vortex trapped within thin films of Nb. The vortex would be induced to move either by thermal depinning or by pushing on the vortex with a transport current in one of the films. Thermal depinning studies show that the temperature of the initial motion of the vortex is independent of applied fields up to +/-20 mG but the temperature where the vortex exits the junction seems to be about 50 mK lower in +/-20 mG than in zero field. Lorentz force depinning studies show that for a vortex pinned in the top Nb film, there is a large difference between the top and bottom film depinning currents. A transport current in the top film will depin a vortex in the top film with about one-tenth the current needed in the bottom film to depin this vortex. Attempts to create artificial pinning sites by depositing Fe balls on the junction were successful with the vortex being pinned to the site of the Fe ball. Attempts to create an artificial pinning site by depressing the order parameter with a thin strip of Au on the surface of the Nb was not successful. Pinning sites in the Nb were not correlated with the location of the Au lines.

Comments
Description
Keywords
Citation
Source
Subject Categories
Copyright
Fri Jan 01 00:00:00 UTC 1999