Method of reducing critical current density of oxide superconductors by radiation damage
AssigneeAT&T Bell Laboratories
InventorsKenneth T. Short, Alice E. White
Life of this patent
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Abstract
The critical current density J.sub.c of a superconductive oxide film can be tailored, without substantial change in the critical temperature T.sub.c (R.dbd.0), by introduction of radiation damage into the superconductor. Exemplarily, this is done by exposure to energetic (e.g., 1 MeV) ions. The ability to tailor J.sub.c permits optimization of SQUIDS and other thin film devices, and makes it possible to produce superconductive interconnects that comprise "fuses" or current limiters.
Claims5
Method of producing an article comprising a layer of superconductive oxide on a substrate, associated with at least a part of the superconductive oxide layer being a critical current density J.sub.cf, the method comprising
- a) forming the layer of superconductive oxide on the substrate;
- and
- b) providing means for making electrical contact with the layer characterized in that
- c) associated with the at least part of the layer formed in step a) is an initial critical current density J.sub.ci, and a critical temperature T.sub.c (R=0), with J.sub.ci >J.sub.cf ;
- and the method comprises
- d) exposing the at least part of the oxide layer to a flux of particles, with the particle species, energy, and fluence selected such that the critical current density of the at least part of the oxide layer is reduced to J.sub.cf with the normalized change .DELTA.T.sub.c in T.sub.c (R=0) being less than 0.2 of the normalized change .DELTA.J.sub.c in J.sub.c, where .DELTA.T.sub.c =(T.sub.cf -T.sub.ci)/T.sub.cf and .DELTA.J.sub.c =(J.sub.ci -J.sub.cf)/J.sub.ci, and T.sub.ci and T.sub.cf are the initial and final value of the critical temperature T.sub.c (R=0), respectively.
Dependencies are inferred from the claim text.