Enhanced critical currents in Bi-2223/Ag sheathed tapes by high energy proton irradiation
- James Y.
- Martin P.
- John L.
- Steve
- Jeffrey O.
We irradiated Bi-2223/Ag sheathed tapes with high-energy protons, causing fission reactions with Bi and Pb nuclei and generating in situ splayed columnar defects in the superconductor core of the tapes. We find that the best 75 K critical-current density J{sub c} performance in an applied magnetic field B perpendicular to the tape plane is achieved at a matching field, for which the flux-quantum density equals the columnar-defect density, of about 1 T. At this defect density, the J{sub c} at 75 K and 1 T perpendicular to the tape plane is almost 100 times larger than that for an unirradiated tape. For higher proton doses, there is increasingly greater grain-boundary damage, lowering the self-field J{sub c} and ultimately degrading the in-field performance. However, much of this damage can be repaired with a short anneal at 400 C. Decreasing the incident proton energy from 800 to 500 MeV has little effect on the enhanced J{sub c} performance and has beneficial side effects. Irradiation of a stack of tapes demonstrates the high penetration power and uniform generation of columnar defects throughout a substantial volume of material. The application of this technique to improved device performance will be discussed.
- Research Organization:
- Los Alamos National Laboratory
- Sponsoring Organization:
- DOE
- OSTI ID:
- 975684
- Report Number(s):
- LA-UR-01-4478
- Country of Publication:
- United States
- Language:
- English
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