Oxide superconductor current lead and method of manufacturing the same

Abstract

An oxide superconductor current lead provided with a rod-like or pipe-like oxide superconductor, at each of end parts of which a metallic electrode is formed. In this oxide superconductor current lead, the oxide superconductor is a Bi,Sr,Ca,Cu,O,superconductor. Further, the metallic-electrode-portion contact resistivity thereof is not more than 0.05 &mgr;&OHgr;·cm,. Moreover, the critical current density is not less than 2,000 A/cm,. Furthermore, there is provided a method of manufacturing such an oxide superconductor current lead. To perform this method, optimum conditions for conducting a heat treatment when forming electrodes at both ends of an oxide superconductor current lead are detected. Thereby, the contact resistivity during a superconducting coil becomes extremely small. Further, the critical current density is considerably enhanced. In the case of this method, an oxide superconductor (,) obtained by finishing a final sintering process is first worked into or shaped like a rod or a pipe. Then, metallic electrode portions (,) are formed by winding metallic foil around end parts of the superconductor, or by applying metallic paste thereto, or by performing a physical vapor phase epitaxy process such as a sputtering process or an evaporation process. Subsequently, a heat treatment is performed on the metallic electrode portions at a temperature, which is in a 810 to 830° C. range, for a time period of 2 to 20 hours. Thus, an oxide superconductor current lead is obtained.