Fabrication and transport properties of an MgB₂solenoid coil

Abstract

This paper reports on the fabrication and testing of an MgB2 coil made by a wind and react method. We made a 130 m-long Fe/Cu-composite sheathed MgB2-superconducting round wire applying an in situ PIT method. Using a 58 m-long wire, we fabricated a small solenoid coil with 459 turns. The Ic of the coil were measured under different external fields and temperatures. Excellent correspondence of Ic between the short sample and the coil was obtained at 4.2 K and in external fields above 4 T. This indicates that the 58 m-long wire has a very homogeneous Ic distribution. At 25 K this coil generated a maximum magnetic field of 1 T (Ic = 100 A, overall-Jc = 200 A mm−2) in an external field of 0.5 T. At 4.2 K this coil generated 1.9 T (Ic = 184 A, overall-Jc = 366 A mm−2) in the external field of 0.5 T. These results demonstrate the possible use of an MgB2 superconducting coil for superconducting magnet applications such as in MRI.

Superconductivity in MgB2

“…The intense development race between Japan, the United States, and Europe is unfolded, and it has progressed rapidly. In 2005, Hitachi Ltd. and the National Institute for Materials Science achieved stability excitation of 1.5 T for a long time, driving the persistent mode, and maintenance of magnetic field for 12 hours leading the application to an MRI magnet [78,79] S.p.A., and Paramed Medical Systems Inc. [80,81]. In 2007, Central Japan Railway Company and Hitachi Ltd. succeeded in enlargement of MgB 2 coil (from diameter 30 to 500 mm) and magnetic levitation of 630 kg weight by a cryogenic-free MgB 2 magnet [82].…”

Fabrication and Transport Critical Current Densities of MgB2/Fe/Cu Multifilament Tapes without Any Intermediate Annealing

“…Cu is an ideal stabilizing metal for low T c superconducting wires and tapes. Copper is advantageous for its low resistance and weak paramagnetic properties but Cu reduces J c values of the MgB 2 composite wire since it reacts with MgB 2 core [24]. The Fe is generally used as a reaction barrier between Cu stabilization material and MgB 2 core [25].…”

Superconducting Properties of MgB<SUB>2</SUB> Particle Impregnated with Mg-Based Alloys

“…4) These characteristics stimulate plenty of research activities to develop suitable processes for producing MgB 2 wires and tapes, which are required for superconducting coil magnets. 5,6) Concerning the basic superconducting property of MgB 2 , many attempts have been made to improve the critical current density (J c ), irreversibility field (B irr ), and upper critical field (B c2 ). Especially J c improvement in MgB 2 has been one of major issues of research; a well known problem is that J c drops rapidly with increasing magnetic field due to its poor flux pinning.…”