The processing of a practical oxide superconductor wire or tape

There has been substantial progress in recent months in the realization of attractive current density in bulk oxide superconductors. Silver sheathed Bi oxide wire or tape has been produced in a number of laboratories with impressive current density exceeding 104 A/cm2 at 4.2 K in magnetic fields as high as 30 T. This result easily eclipses the performance of conventional 4.2K conductors such as Nb-Ti and Nb3Sn, which presents a promise for using oxide conductors for high field magnets. At 77 K similar success have been achieved for Y-Ba-Cu-O bulk materials following various melt processing procedures with the observation of current density near 104 A/cm2 at useful magnetic fields of 1-4 T. There is some question as to whether any of these materials can be formed in long lengths with sufficient mechanical strength and stability to allow operation at high fields in magnet applications. This paper reviews the current progress in producing oxide superconductor wire or tape and a prognosis as to when a practical oxide conductor is realized