Development of High Performance Superconducting Materials and Wires for Next Generation

本研究的目标是提高下一代高温超导体的化学和结构稳定性以及临界电流密度，并建立在液氮温度下实际应用的短和长长度导体的制造方法。虽然已知汞（Hg）基铜酸盐超导体在化学上相当不稳定，并且其制备方法并不简单，但是我们已经发现，掺杂少量过渡离子如铼（Re）或铬（Cr）在化合物的稳定性方面是相当有效的。采用熔体凝固法在体带材和厚膜带材中成功地生长了掺Re的Hg-Ba-Ca-Cu-O单晶。Ag/Cr涂层Ni箔是最受欢迎的Hg基带材基底。阐述了重掺Pb、氧控Bi 2212单晶磁通钉扎性能提高的机理。Bi（Pb）2212的加工技术还开发了Ag复合带材。

The goal of the present research are to improve the chemical and Structural stability and critical current densities of high temperature superconductors for next generation and to establish the manufacturing method for short and long length conductors for practical applications at liquid nitrogen temperature. While the mercury(Hg)-based cuprate superconductors have been known to be chemically rather unstable and its preparation process is not simple, we have found that doping of a small amount of transition ions such as rhenium(Re) or chromium(Cr) is quite effective in stabilization of the compounds. Single crystals of Re-doped Hg-Ba-Ca-Cu-O were successfully grown in both bulk and thick film tapes by the melt-solidification method. The Ag/Cr coated Ni foil wag found to be the moat favorite substrate for Hg-based tapes. Mechanisms of the improved flux pinning properties of heavily Pb-doped and oxygen controlled Bi2212 single crystal were elucidated. Processing techniques of Bi(Pb)2212./Ag composite tapes has been also developed.