Fabrication and Characteristics of a Test Magnet from HTS Bi-2223 Silver-Clad Tapes
Critical currents of powder-in-tube processed silver-clad Bi-2223 short tape samples and coils have been measured at liquid nitrogen (77 K), liquid neon (27 K), and liquid helium (4.2 K) temperatures. The short samples have been characterized in fields up to 20 T and indicate a large anisotropy at 27 K with resistive behavior above 15 T in the worst field direction. A test magnet consisting of three double-pancake coils generated magnetic fields greater than 1.0, 0.7 and 0.1 T at 4.2, 27, and 77 K, respectively. Moreover, in background fields up to 14.5 T at 4.2 and 27 K, the test magnet also generated significant self-fields. Optimization of thermomechanical process parameters have yielded Jcs in the superconducting core >4.0 × 104 A/cm2 at 77 K, zero field and >2.0 × 105 A/cm2 at 4.2 K, zero field for short tape samples. Long lengths (> 30 m) of silver-clad tape superconductors have also been fabricated and tested to carry significant amounts of current (Jc core > 10,000 A/cm2) at 77 K. Critical current data of short and long samples and characteristics of the test magnet are reported.
KeywordsLiquid Helium Critical Current Density Background Field Background Magnetic Field Test Magnet
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