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In-situ sputtering of YBCO films for microwave applicationsRF magnetron sputtering from a single YBCO target onto a heated substrate (700 C) was used to obtain c-axis-oriented 1-2-3 films that are superconducting without a subsequent annealing or oxygenation step, with Tc(R = 0) as high as 88 K on MgO and LaAlO3 substrates. This process uses an 8-in-diameter target in the sputter-up configuration, with a central grounded shield to eliminate negative ion bombardment. It can reproducibly and uniformly cover substrates as large as 3-in across at rates exceeding 1 A/s. Maintaining film composition very close to stoichiometry is essential for obtaining films with good superconducting properties and surface morphology. Optimum films have critical currents of 1 MA/sq cm at 77 K. Measurements of microwave surface resistance based on a stripline resonator indicate low surface resistance for unpatterned YBCO ground planes, but excess loss and a strong power dependence in a patterned center strip.
Document ID
19910051417
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Ballentine, P. H.
(CVC Products, Inc. Rochester, NY, United States)
Kadin, A. M.
(CVC Products, Inc. Rochester, NY, United States)
Mallory, D. S.
(Rochester, University NY, United States)
Date Acquired
August 15, 2013
Publication Date
March 1, 1991
Publication Information
Publication: IEEE Transactions on Magnetics
Volume: 27
ISSN: 0018-9464
Subject Category
Solid-State Physics
Accession Number
91A36040
Distribution Limits
Public
Copyright
Other

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