ABSTRACT
The sudden emergence of high-temperature superconductors (HTS) [1-3] has sparked tremendous interest and inspired a vast amount of scientific work. Following the discovery of HTS materials, a great deal of effort has also been focused on conductor processing with the aim of realizing high-field and/or high-temperature superconducting magnets and electric power application. Critical requirements for the magnet conductors are 1.) high critical current density, Jc, 2.) workability for fabricating long wires, and 3.) mechanical and thermal stability realized by a metal sheath. Among the various processes proposed, the power-in-tube (PIT) method is now the most promising. The powder-in-tube method wire using (Bi,Pb)2Sr2Ca2Cu3O10+á (Bi-2223) phase approaches the above-mentioned requirements. Recently, values of 66,000 and 69,000 A/cm2 were attained for the Jc at 77 K for short samples [4-6] and above 20,000 A/cm2 for 100 m-long wires [7,8]. The length reached 1000 m with the Jc at 77 K of 12700 A/cm
2 [8]. The 0.2% yield strength increased from a few tens megapascals of pure Ag-sheathed wire to about 200 MPa of Ag-MgO sheathed wire [9]. These values are not yet satisfactory but are sufficient for some applications.
