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Magneto Optic Inspection of Thin Film Superconductors

IP.com Disclosure Number: IPCOM000109144D
Original Publication Date: 1992-Jul-01
Included in the Prior Art Database: 2005-Mar-23
Document File: 1 page(s) / 70K

Publishing Venue

IBM

Related People

Dinger, TR: AUTHOR [+3]

Abstract

High temperature superconductors are multicomponent, structurally-sensitive and chemically-reactive. Consequently, they have properties that are very sensitive to small processing variations. Depositing high temperature superconducting films with uniform properties over an area much greater than one cm2 is achievable but is presently a complex task using standard laser ablation or sputtering deposition techniques. However, several potential applications, such as superconducting transmission lines or high frequency microwave devices, require single layers of superconducting film with uniform electrical characteristics over relatively large areas. For these applications, we propose that superconducting film areas with acceptable properties be identified prior to patterning by using a magneto-optic technique.

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Magneto Optic Inspection of Thin Film Superconductors

      High temperature superconductors are multicomponent,
structurally-sensitive and chemically-reactive. Consequently, they
have properties that are very sensitive to small processing
variations.  Depositing high temperature superconducting films with
uniform properties over an area much greater than one cm2 is
achievable but is presently a complex task using standard laser
ablation or sputtering deposition techniques.  However, several
potential applications, such as superconducting transmission lines or
high frequency microwave devices, require single layers of
superconducting film with uniform electrical characteristics over
relatively large areas.  For these applications, we propose that
superconducting film areas with acceptable properties be identified
prior to patterning by using a magneto-optic technique.

      A thin magneto-optic film, such as amorphous, insulating
EuS/EuF2 with a resolution of ~ 2 mm, is deposited directly onto the
superconductor.  In an applied magnetic field, the magnetooptic layer
provides a measure of the film's uniformity by imaging the magnetic
field penetration into the superconductor.  Once the film is imaged
and the areas of the superconductor which best screen a magnetic
field are chosen, the superconductor/insulator structure is
patterned.  The superconductor can be imaged with the overlying
magneto-optic film after etching a pattern and, in some cases, can be
used...