MgB$_{2}$ tapes and metallic superconductors update

The development of MgB/sub 2/ tapes and the recent metallic superconductors was reviewed. MgB/sub 2/ tapes and wires are developed by the so-called powder-in-tube method. However, their critical current densities, J/sub c/, are still below the practical level. Research and development such as introduction of pinning centers is required for the J/sub c/ enhancement. Improvement of practical superconductors, Nb-Ti and Nb/sub 3/Sn, is now in progress for realizing new applications such as the Large Hadron Collider, high-field NMR system, ITER magnet and cryocooler-cooled magnet. Nb /sub 3/Al has gained interest because of its high mechanical tolerance. Recently, Nb/sub 3/Al tapes and wires with excellent high field performance were developed by the application of rapid heating, quenching and transformation method. (38 refs).