Determination of irreversibility field variations in mono- and multifilamentary (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} tapes by transport current methods
- Applied Superconductivity Center and Materials Science Program, University of Wisconsin--Madison, Madison, Wisconsin 53706 (United States)
The irreversibility field, H{sup {asterisk}}, has been measured for a variety of mono- and multifilamentary (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} (2223) tapes using two different transport current techniques. It is common to characterize the quality of 2223 tapes by their zero-field, 77 K critical current density [J{sub c}(0T, 77 K)], even though this ignores the fact that significant self-fields depress J{sub c}(0T,77K) and the possibility that the in-field J{sub c}(B) characteristics may be optimized independently of the J{sub c}(0T,77K) value. To provide more useful information, we propose a second characterization, that of the irreversibility field, H{sup {asterisk}}. Having both H{sup {asterisk}} and J{sub c}(0T,77K) information helps in separating the two independent contributions that better connectivity and stronger flux pinning can make to the J{sub c} of a tape. We illustrate this point with results from a variety of mono- and multifilamentary Bi-2223/Ag tapes in damaged and undamaged conditions, which show that H{sup {asterisk}} (77 K) can vary from {approximately}100 to {approximately}200mT and not directly correlate with J{sub c}(0T,77K). The two proposed protocols for H{sup {asterisk}} measurement are robust and compatible with common transport measurement procedures. {copyright} {ital 1997 American Institute of Physics.}
- OSTI ID:
- 565559
- Journal Information:
- Applied Physics Letters, Vol. 71, Issue 26; Other Information: PBD: Dec 1997
- Country of Publication:
- United States
- Language:
- English
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