Prediction of the J C (B) Behavior of Bi-2212 Wires at High Field
Bi-2212 wires have been produced for much of the last decade with varying architectures, powder sources and great variability of final Jc(B) properties. As Bi-2212 transitions from an R&D materials development to a magnet technology, means to predictably forecast Jc(B) become increasingly valuable. Here we report on characterizations of short samples having Jc(15T, 4.2 K) varying from 1210 to 6560 A/mm2, measured in fields up to 31 T, and drawn from 10 billets. Using both 4 K transport and variable temperature VSM measurements capable of probing the 20 K irreversibility field, Birr = μ0Hk, we discovered that the vortex pinning properties are very stable across these wires, which all used the same standard powder composition (Bi2.17Sr1.94Ca0.89Cu2.00O8+x), even though it has been made by three different manufacturers over nine years. We conclude that a power-law fit Jc∝B-α, where α = 0.280 (σ = 0.015), works well at 4.2 K over the field range of at least 3-30 T and that μ0Hk(20 K) remains stable at 8.6 ± 0.4 T. We conclude that the dominant current limiting mechanism predicting Jc(B) in Bi-2212 is the effective filament connectivity. Jc(B) at high fields may thus be predicted by simple Ic measurements at easily accessible fields in the 3-15 T range.
- Research Organization:
- Florida State Univ., Tallahassee, FL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), High Energy Physics (HEP)
- Grant/Contract Number:
- SC0010421
- OSTI ID:
- 1506068
- Journal Information:
- IEEE Transactions on Applied Superconductivity, Vol. 29, Issue 5; Conference: Applied Superconductivity Conference, Seattle,WA (United States), 28 Oct - 02 Nov 2018; ISSN 1051-8223
- Publisher:
- Institute of Electrical and Electronics Engineers (IEEE)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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