Dissertation/Thesis Abstract

Hyperboloid-Parameterized Description of Diffusive Superconducting-Magnetic Hybrid Systems
by Chan, Brendan K., M.S., California State University, Long Beach, 2017, 90; 10606400
Abstract (Summary)

We present a study of diffusive Josephson junctions made of two superconductors connected by a magnetic heterostructure. When the link is sufficiently thin, Cooper pairs can tunnel from one superconductor to the other, generating a Josephson current. Junctions with inhomogeneous magnetization are of particular interest because they may display triplet pair correlations with non-zero spin projection along the quantization axis. The generation of these correlations in the hybrid structure is studied by solving numerically the Usadel equations. In previous works, we have shown for example that the rotation of the magnetization can be used to tune the relative weight of the singlet and triplet pair correlations, thereby tuning the current. Here we present a novel approach to the numerical treatment of the Usadel equations, using a parameterization that takes automatically into account a required constraint of the model. The method significantly reduces the computational time, allowing us to calculate the Gor'kov functions self-consistently and extend the model to include the inverse proximity effect. We show results for SF and SFS systems with a helical magnetization profile for various twisting angles.

Indexing (document details)
Advisor: Bill, Andreas
Commitee: Jaikumar, Prashanth, Peterson, Michael
School: California State University, Long Beach
Department: Physics and Astronomy
School Location: United States -- California
Source: MAI 56/06M(E), Masters Abstracts International
Subjects: Physics
Keywords: Condensed matter theory, Gor'kov, Magnetic proximity systems, Magnetism, Superconductivity, Usadel
Publication Number: 10606400
ISBN: 978-0-355-23034-5
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