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Title:Superconducting Transition-Edge Sensor Physics
Author(s):Sadleir, John E.
Director of Research:Robinson, Ian K.
Doctoral Committee Chair(s):Chiang, Tai-Chang
Doctoral Committee Member(s):Robinson, Ian K.; Errede, Steven M.; Selvin, Paul R.
Department / Program:Physics
Discipline:Physics
Degree Granting Institution:University of Illinois at Urbana-Champaign
Degree:Ph.D.
Genre:Dissertation
Subject(s):Superconductivity
Superconductors
proximity effect
inverse proximity effect
superconducting weak-link
SNS
NSN
SNS weak links
SN'S weak links
SS'S
SN heterostructures
superconducting normal-metal heterostructures
critical current effects
rectification
critical current asymmetry
Ic asymmetry
edge-barrier critical current
geometric barrier critical current
stress effects in superconducting thin films
Transition Edge Sensors(TES)
superconducting transition edge sensors
superconducting transition edge sensors(TES)
Superconducting phase thermometers
Percolation theory
random superconducting resistor network
nonequilibrium superconductivity
longitudinal proximity effect
lateral inverse proximity effect
x-ray detectors
microcalorimeters
quantum calorimeters
quantum microcalorimeters
bolometers
microwave bolometers
infra-red bolometers
Josephson Effect
Fraunhofer pattern
Fraunhofer interference pattern
Fraunhofer diffraction pattern
superconducting molybdenum thin films
paraconductivity
Josephson weak-link
superconducting normal metal bilayers
SN trilayers
superconducting transition
superconducting phase transition
superconducting phase transition width
transition width
superconducting resistive transition
resistive transition width
excess current effects
R(I,T) surface
R(I,T,B) surface
magnetic flux quantization
exponential critical current
superconducting critical length
spatially varying superconducting order parameter
spatial variation of the superconducting order parameter
superconducting transition temperature
critical current evolution
Josephson critical current
nonuniform superconductivity
Longitudinal proximity effect
longitudinal proximity e ect (LoPE)
Lateral Inverse Proximity Effect
lateral inverse proximity e ffect (LaiPE)
Self-fielding effects
flux focusing
Abstract:Despite record-setting performance demonstrated by superconducting Transition Edge Sensors (TESs) and growing utilization of the technology, a theoretical model of the physics governing TES devices superconducting phase transition has proven elusive. Earlier attempts to describe TESs assumed them to be uniform superconductors. Sadleir et al. 2010 shows that TESs are weak links and that the superconducting order parameter strength has significant spatial variation. Measurements are presented of the temperature T and magnetic field B dependence of the critical current Ic measured over 7 orders of magnitude on square Mo/Au bilayers ranging in length from 8 to 290 microns. We find our measurements have a natural explanation in terms of a spatially varying order parameter that is enhanced in proximity to the higher transition temperature superconducting leads (the longitudinal proximity effect) and suppressed in proximity to the added normal metal structures (the lateral inverse proximity effect). These in-plane proximity effects and scaling relations are observed over unprecedentedly long lengths (in excess of 1000 times the mean free path) and explained in terms of a Ginzburg-Landau model. Our low temperature Ic(B) measurements are found to agree with a general derivation of a superconducting strip with an edge or geometric barrier to vortex entry and we also derive two conditions that lead to Ic rectification. At high temperatures the Ic(B) exhibits distinct Josephson effect behavior over long length scales and following functional dependences not previously reported. We also investigate how film stress changes the transition, explain some transition features in terms of a nonequilibrium superconductivity effect, and show that our measurements of the resistive transition are not consistent with a percolating resistor network model.
Issue Date:2011-01-21
URI:http://hdl.handle.net/2142/18616
Rights Information:Copyright 2010 John E. Sadleir
Date Available in IDEALS:2011-01-21
2013-01-22
Date Deposited:2010-12


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