Transport Properties of PIT-processed MgB₂ Wire and Coil

Abstract

This paper reports on the successful fabrication and testing of a MgB₂ coil. We have fabricated a 15 m-long MgB₂/stainless steel mono-core tape using a mixture of commercial MgB₂ powder and tin powder (10wt% of MgB₂ powder) using the PIT method. The tape is made applying an ex-situ process without any heat treatment during the processing procedure. The MgB₂ superconducting tapes show good uniformity, with a high J_c value (180-290 A/mm² at 4.2 K and 3 T) along the tape's length, as well as good bending tolerance. I_c degradation of the tape occurred at a bending strain of as high as 1.3%. Using wire over 12 m-long, we made a small solenoid coil, 48.5 mm in outer diameter and 40 mm height, and tested it at 4.2 K and self-field. The highest I_c value we obtained was 255 A, which generated a central field of 0.5 T, and a maximum magnetic field of 0.575 T.