Large field generation with Hot Isostatically Pressed Powder-in-Tube MgB2 coil at 25 K

Abstract

We present the fabrication and test results of Hot-Isostatic-Pressed (HIPed) Powder-in-Tube (PIT) MgB${}_2$ coils. The coils properties were measured by transport and magnetization at different applied fields ($H$) and temperatures ($T$). The engineering critical current ($J_e$) value is the largest reported in PIT MgB${}_2$ wires or tapes. At 25 K our champion 6-layer coil was able to generate a field of 1 T at self-field ($I_c>$ 220 A, $J_e\sim 2.8\times 10^4$ A/cm${}^2$). At 4 K this coil generated 1.6 T under an applied field of 1.25 T ($I_c\sim 350$ A, $J_e\sim 4.5\times 10^4$ A/cm${}^2$). These magnetic fields are high enough for a superconducting transformer or magnet applications such as MRI. A SiC doped MgB${}_2$ single layer coil shows a promising improvement at high fields and exhibits $J_c>10^4$ A/cm${}^2$ at 7 T.

8 pages 3 figures