Chitra, R Nayak; Dr.Kuriakose, V C(Cochin University of Science and Technology, October , 2008)
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Abstract:
The main goal of this thesis is to study the dynamics of Josephson
junction system in the presence of an external rf-biasing.A system of
two chaotically synchronized Josephson junction is studied.The change in the dynamics of the system in the presence of at
phase difference between the applied fields is considered. Control of
chaos is very important from an application point of view. The role
Of phase difference in controlling chaos is discussed.An array of three Josephson junctions
iS studied for the effect of phase difference on chaos and synchronization
and the argument is extended for a system of N Josephson junctions. In the presence of a phase difference between the external
fields, the system exhibits periodic behavior with a definite phase relationship
between all the three junctions.Itdeals with an
array of three Josephson junctions with a time delay in the coupling
term. It is observed that only the outer systems synchronize while
the middle system remain uncorrelated with t-he other two. The effect
of phase difference between the applied fields and time-delay on
system dynamics and synchronization is also studied. We study the influence of an applied ac biasing on a serniannular
Josephson junction. It is found the magnetic field along with the
biasing induces creation and annihilation of fluxons in the junction.
The I-V characteristics of the junction is studied by considering the
surface loss term also in the model equation. The system is found to
exhibit chaotic behavior in the presence of ac biasing.
Description:
Department of Physics,
Cochin University of Science and Technology
Shaju,P D; Kuriakose, V C(Cochin University of Science and Technology, 2002)
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Abstract:
The thesis deals with detailed theoretical analysis of fluxon dynamics in single and in coupled Josephson junctions of different geometries under various internal and external conditions. The main objective of the present work is to investigate the properties of narrow Long Josephson junctions (LJJs) and to discuss the intriguing physics. In this thesis, Josephson junctions of three types of geometries, viz, rectangular, semiannular and quarter annular geometries in single and coupled format are studied to implement various fluxon based devices. Studies presented in this thesis reveal that mulistacked junctions are extremely useful in the fabrication of various super conducting electronic devices. The stability of the dynamical mode and therefore the operational stability of the proposed devices depend on parameters such as coupling strength, external magnetic fields, damping parameters etc. Stacked junctions offer a promising way to construct high-TC superconducting electronic components. Exploring the complex dynamics of fluxons in coupled junctions is a challenging and important task for the future experimental and theoretical investigations