Fabrication and transport properties of MgB2 wire and coil

The paper reports the first successful fabrication and test of a MgB2 coil. We have fabricated 15 m long MgB2-superconducting wires by a powder-in-tube method using Ni-sheath without any heat treatments during the processing. The MgB2/Ni tape has a good uniformity of high J(c) value (500-600 A/mm(2) at 4.2 K and 0 T) along the tape length as well as a nice bending tolerance. I-c degradation of the tape occurred at the bending strain of as high as 1%. Using a 10 m long Ni-sheath tape, we have made a small solenoidal coil with 80 turns to be tested in liquid helium. The coil showed a typical training effect, I-c increasing by repeating the excitation, and the highest I-c value we obtained was 105 A, which generated the central field of 0.13 T. (C) 2002 Elsevier Science B.V. All rights reserved.