VAMAS critical current round robin test on a 2212 BSCCO Ag-sheathed tape

Aiming at the establishment of a reliable critical current, I/sub c/, a measurement method for oxide superconductors, a round robin test (RRT) has been implemented in Japan in the framework of VAMAS (Versailles Project on Advanced Materials and Standards), using a 2212 BSCCO Ag-sheathed tape conductor. In this RRT each participant received two pre-instrumented and pre-measured specimens and one freestanding specimen. Measurements were made at 4.2 K and magnetic fields ranging from 0 to 10 T. One of the pre-instrumented specimens was also routed among participants as a RRT specimen. Together with the RRT specimen, a superconductor I-V simulator was circulated to intercompare the I-V measurement set-ups used at participant labs. Measurements on pre-instrumented specimens have shown that I/sub c/ of Ag-sheathed tapes is sensitive to the heat cycle, which may be attributed to the deformation of the oxide superconductor by swelling and/or to the formation of cracks inside the oxide layer.<
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