STRUCTURE AND SUPERCONDUCTIVITY OF ROOM-TEMPERATURE CHEMICALLY OXIDIZED SS-THAN-OR-EQUAL-TO-X-LESS-THAN-OR-EQUAL-TO-0.5)(Y (0)

Room temperature chemical oxidation has been used for the insertion of oxygen into the T/O phase of La2-xNdxCuO4 (x less than or equal to 0. 5). The influence of interstitial oxygen on both the structural featur es and the physical properties of this series of cuprates is worth a s tudy. The excess of oxygen introduced in the semiconducting starting m aterials relieves partially the distortion of the structure, which inc reases for increasing Nd content, and provides the hole doping require d for superconductivity. The extra oxygen content decreases along this series of compounds as the Nd-doping increases, probably due to the p rogressive contraction of the structure along the c-axis. Analogies an d differences in the modifications induced by the oxidation process in the present La2-xNdxCuO4+y materials and in related compounds La2-x(C a/Sr/Ba)(x)CuO4+y (x less than or equal to 0.15) are reported and disc ussed. (C) 1997 Elsevier Science B.V.