University of Illinois Urbana-Champaign

Superconducting Transition-Edge Sensor Physics

Sadleir, John E.

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https://hdl.handle.net/2142/18616

Description

Title
Superconducting Transition-Edge Sensor Physics
Author(s)
Sadleir, John E.
Issue Date
2011-01-21T22:51:46Z
Director of Research (if dissertation) or Advisor (if thesis)
Robinson, Ian K.
Doctoral Committee Chair(s)
Chiang, Tai-Chang
Committee Member(s)
  • Robinson, Ian K.
  • Errede, Steven M.
  • Selvin, Paul R.
Department of Study
Physics
Discipline
Physics
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(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 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.
Graduation Semester
2010-12
Permalink
http://hdl.handle.net/2142/18616
Copyright and License Information
Copyright 2010 John E. Sadleir

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