We have observed superconductivity in Bi-Sr-Cu oxide near a nominal composition of ${\mathrm{Bi}}_{1.49}$${\mathrm{Sr}}_{1.68}$ ${\mathrm{Cu}}_{3.0}$${\mathrm{O}}_{7.05}$. Resistive transition temperatures $T_c^{R=0\mathrm{}}$ vary between 3.5 and 5.4 K. The samples are crystallographically different from the presently known high-temperature superconductors.

• Received 16 February 1988

DOI:https://doi.org/10.1103/PhysRevB.38.754