Semifluxons in long Josephson junctions with phase shifts

Ahmad, Saeed (2012) Semifluxons in long Josephson junctions with phase shifts. PhD thesis, University of Nottingham.

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A Josephson junction is formed by sandwiching a non-superconducting material between two superconductors. If the phase difference across the superconductors is zero, the junction is called a conventional junction, otherwise it is unconventional junction. Unconventional Josephson junctions are widely used in information process and storage.

First we investigate long Josephson junctions having two p-discontinuity points characterized by a shift of p in phase, that is, a 0-p-0 long Josephson junction, on both infinite and finite domains. The system is described by a modified sine-Gordon equation with an additional shift q(x) in the nonlinearity. Using a perturbation technique, we investigate an instability region where semifluxons are spontaneously generated. We study the dependence of semifluxons on the facet length, and the applied bias current.

We then consider a disk-shaped two-dimensional Josephson junction with concentric regions of 0- and p-phase shifts and investigate the ground state of the system both in finite and infinite domain. This system is described by a (2 + 1)

Item Type: Thesis (University of Nottingham only) (PhD)
Supervisors: Susanto, H.
Wattis, J.A.D.
Subjects: Q Science > QA Mathematics > QA299 Analysis
Faculties/Schools: UK Campuses > Faculty of Science > School of Mathematical Sciences
Item ID: 12729
Depositing User: EP, Services
Date Deposited: 20 Sep 2012 11:25
Last Modified: 13 Sep 2016 22:05

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