The effect of indium substitution for copper on the superconductivity of the electron-doped system Nd-Ce-Cu-O

• Published in: Physica. C, Superconductivity Superconductivity, 1990-09, Vol.170 (3), p.211-214
• Main Authors: Ayoub, N.Y., Almasan, C.C., Early, E.A., Markert, J.T., Seaman, C.L., Maple, M.B.
• Format: Article
• Language: English
• ISSN: 0921-4534; 1873-2143
• DOI: 10.1016/0921-4534(90)90312-3

Electrical resistivity and magnetic susceptibility measurements on the new electron-doped Nd 2− x Ce x Cu 1− z In z O 4− y superconductors are reported. Replacing 3% of Cu 2+ with In 3+ in the non-superconducting compound Nd 1.88 Ce 0.12 CuO 4− y yields superconductivity with an onset superconducting critical temperature T c ≈23 K. The combined substitution of Ce 4+ and In 3+ with x+ z in the range 0.15 to 0.17 affects T c in a similar way as the substitution of Ce 4+ alone (z = 0) where electrons are supplied from outside the CuO 2 planes. Furthermore, for x+ z = 0.15 (i.e., constant electron concentration), we find that T c remains relatively constant (∽24 K), while Δ T c increases with increasing z from 4 K at z = 0 to 19.4 K at z = 0.04.