Superconductivity in the series of compounds Sr2Can-1CunOy (n = 1 approx. 4) prepared under high pressure

Article abstract of DOI:10.1016/0921-4534(96)00314-0

A series of compounds Sr₂Ca_n-1Cu_nO_y (n = 1-4) were prepared under 5-6 GPa and their superconducting properties were examined. The n = 1 member of the series, Sr₂CuO_3+δ, has been believed as a superconductor with T_c of 70 K. However, our experiments suggest strongly that it is not superconducting but the 70 K superconductivity is ascribed to the n = 2 member of the series, Sr₂CaCu₂O_y. The n = 3 and 4 members were also prepared and they were confirmed to have T_c's of 109 and 83 K, respectively.