Preparation of a single phase sample of (Bi1−xCux)Sr2YCu2Oy and its physical properties

A single-phase sample of the (Bi1−xCux)Sr2YCu2Oy (Bi- 1:2:1:2) phase was successfully prepared. In order to obtain the pure sample, control of both the nominal composition and the sintering condition were required. In spite of increase in the Cu valence, the sample remained semiconducting. The hole density measured by Hall effect was estimated to be 3.6 × 1020 cm−3, indicating that a sufficient hole necessary for occurrence of superconductivity was not doped into the CuO2 plane.