Dissertation/Thesis Abstract

Pair correlations in clean magnetic Josephson junctions
by Leal, Luis Stephan, M.S., California State University, Long Beach, 2016, 56; 10194250
Abstract (Summary)

Superconducting pairs are able to leak into non-superconducting materials when placed in close proximity. In the presence of ferromagnetism pair correlations are modified by the magnetization; singlet Cooper pairs transform into a mixture of singlet and triplet correlations. In this work we analyze how pair correlations are modified in a magnetic Josephson junction in the clean limit, and consider the effect of different magnetic configurations. We use a tight-binding Hamiltonian and the Bogoliubov-de Gennes(BdG) formalism, to describe the proximity system. Applying the Bogoliubov-Valatin transformation we generate the BdG equations in matrix form. We use an iterative process to diagonalize the matrix together with solving the self-consistency relation for the pair potential Δ numerically. From the solution we construct Gor'kov functions which are used to describe the pair amplitudes and Josephson current through the junction. Taking the simplest case first we apply our method to a normal metal Josephson junction and match our model to known results. We then apply it to a homogeneous magnetic Josephson junction and investigate how certain parameters such as magnetization and temperature affect the properties of the junction. Finally our methodology is applied to an inhomogeneous magnetic Josephson junction, to study the differing effects between gradual and abrupt changes in the magnetization on the pair correlations.

Indexing (document details)
Advisor: Bill, Andreas
Commitee: Gu, Jiyeong, Peterson, Michael
School: California State University, Long Beach
Department: Physics and Astronomy
School Location: United States -- California
Source: MAI 56/02M(E), Masters Abstracts International
Subjects: Condensed matter physics
Keywords: Josephson junctions, Pair correlations
Publication Number: 10194250
ISBN: 978-1-369-32016-9
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