Evidence for superior current carrying capability of iron pnictide tapes under hydrostatic pressure

Babar Shabbir, He Huang, Chao Yao, Yanwei Ma, Shixue Dou, Tom H. Johansen, Hideo Hosono, Xiaolin Wang

Research output: Contribution to journalArticleResearchpeer-review

15 Citations (Scopus)

Abstract

High critical current density (J(c)) values in superconducting wires/tapes are desirable for high magnetic field applications. Recently developed pnictide wires/tapes exhibit exceptional superconducting properties such as high critical temperature (T-c), upper critical field (H-c2), and almost field-independent J(c). Despite the great fabrication efforts, however, the newly discovered pnictidewires/tapes are still not able to replace low-temperature superconductors such as Nb3Sn, due to their inferior J(c) values. Ag-clad Sr0.6K0.4Fe2As2 tapes have demonstrated significant superconducting performance, although their low J(c) in comparison to Nb3Sn is still a major challenge. By successfully employing hydrostatic pressure, a remarkably significant enhancement of J(c) by an order of magnitude can be achieved in Sr0.6K0.4Fe2As2 tapes in both low and high fields. This is a promising technological step forward towards high-field applications, as the record high J(c) values (similar to 2 x 10(5) A/cm(2) at 4.2 K and 13 T, P = 1.1GPa) obtained for Sr0.6K0.4Fe2As2 tape are superior to those of Nb3Sn and other pnictide wires/tapes. Here, we used magnetic J(c) data for comparison to the other reported transport J(c) data, due to the lack of transport measurement facility under hydrostatic pressure. Our systematic analysis shows that pressure-induced pinning centers are the main source of J(c) enhancement, along with a fractional contribution from geometric changes around the grain boundaries under pressure. We expect that utilization of an appropriate pressure approach will be a way to significantly enhance J(c) to beyond the cutoff (maximum) values in various superconductors produced using other existing methods for J(c) enhancement.
Original languageEnglish
Article number044805
Number of pages7
JournalPhysical Review Materials
Volume1
Issue number4
DOIs
Publication statusPublished - Sep 2017
Externally publishedYes

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