DocumentCode :
955208
Title :
Critical current density in superconducting niobium films
Author :
Huebener, R.P. ; Kampwirth, R.T. ; Martin, R.L. ; Barbee, T.W., Jr. ; Zubeck, R.B.
Author_Institution :
Argonne National Laboratory, Argonne, Ill.
Volume :
11
Issue :
2
fYear :
1975
fDate :
3/1/1975 12:00:00 AM
Firstpage :
344
Lastpage :
346
Abstract :
We have measured the critical current at 4.2 K in Nb-strips of 1 μm thickness and different width, w, prepared by electron-beam vacuum-deposition. The substrate temperature during the deposition was varied between room temperature and 800°C. The width of the Nb strips ranged between 20 and 300 μm. Whereas up to 600°C the different substrate temperatures yielded about the same average critical current density, Jc, (critical current divided by sample cross section) the specimens prepared with 800°C substrate temperature showed a reduction of Jcby a factor of 4-6. In zero applied magnetic field the samples prepared with 400°C substrate temperature or lower showed a decrease of Jcroughly proportional to w-1/2. Our critical current data obtained in an applied perpendicular field, for the high-field regime, were compared with Kramer´s theory of flux pinning which assumes plastic shearing of the flux-line lattice around individual pinning sites during flux flow.
Keywords :
Conducting films; Superconducting materials; Critical current; Critical current density; Current measurement; Flux pinning; Magnetic fields; Niobium; Strips; Superconducting films; Temperature; Thickness measurement;
fLanguage :
English
Journal_Title :
Magnetics, IEEE Transactions on
Publisher :
ieee
ISSN :
0018-9464
Type :
jour
DOI :
10.1109/TMAG.1975.1058718
Filename :
1058718
Link To Document :
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