Critical Current Density Improvement in Type II Superconductors by Modifying the Type, Size and the Patterns of Pinning Centers

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Nazifi Takantapeh, Rana | 2015

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Type of Document: M.Sc. Thesis
Language: Farsi
Document No: 47239 (04)
University: Sharif University of Technology
Department: Physics
Advisor(s): Vesaghi, Mohammad Ali; Fardmanesh, Mehdi
Abstract:
Motion of magnetic flux, as a result of exerting electrical current, causes dissipation and voltage difference in the type II superconducting slab. So fixing these vortices by pinning centers will increase the critical current . Enhancing the critical current by different kinds of pinning centers is interesting for a lot of theoretical and experimental research groups. At first in this project dynamics of vortices in a triangular lattice is investigated by changing the pinning force. For the case of fp=2f0 we have seen two phase transition in velocity-force plot. And also a practical pinning array of parallel lines is presented. The effect of pinning force, pinning potential width and the distance between the lines is evaluated. when we have fp=5f0 boarder peak is observed in critical current diagram. It is possible to change the place of the peak by changing the distance between lines. Quasi periodic parallel lines has been also investigated. The best array is periodic parallel lines
Keywords:
Superconductivity ; Critical Current ; VORTEX ; Pinning