摘要
Recently, a discovery of new high T<sub>c</sub> oxide superconductor Bi-Sr-Ca-Cu-O has aroused special attention because of the nonexistence of rare-earth elements in it and its high T<sub>c</sub><sup>[</sup>1]. However, the preparation of high T<sub>c</sub> oxide of Bi-Sr-Ca-Cu-O was not easy. Usually, two dif ferent superconducting transitions were found, and their resistivity drops sharply around 110 K but a long tail down to even lower than liquid N<sub>2</sub> temperature was held in the
