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US 5,344,816 AGranted
Stable high oxidation state superconducting oxides
AssigneeHughes Aircraft Company
InventorsRicardo C. Pastor, Antonio C. Pastor, deceased, Luisa E. Gorre, deceased, Keith C. Fuller
Life of this patent
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Abstract
High temperature superconducting oxide materials can be taken to a higher, but stable, state of oxidation by removing H-impurities, such as OH.sup.-, using I.sub.2 /O.sub.2 mixtures in a reactive atmosphere process. A higher T.sub.c and a narrower .DELTA.T-transition result.
Claims9
A process for increasing the superconducting transition temperature and narrowing the .DELTA.T-transition in a high critical temperature (T.sub.c) superconducting oxide comprising:
- (a) heating a superconducting oxide selected from the group consisting of YBa.sub.2 Cu.sub.3 O.sub.7-x, Bi.sub.4 Ca.sub.3 Sr.sub.3 Cu.sub.4 O.sub.16+x, and La.sub.2 CuO.sub.4, wherein x is the variation in oxygen stoichiometry, to a temperature ranging from about 850.degree. C. to below the melting point of said oxide;
- and
- (b) treating said oxide with a flowing gas reactive mixture consisting of oxygen and iodine at said temperature to increase the oxidation state of said oxide to a higher oxidation state and avoid absorption of iodine by said oxide, said gas reactive mixture comprising about 1 to 5 mm of Hg of iodine and the balance oxygen in a total atmosphere of about one atm.
Dependencies are inferred from the claim text.