⁶³,⁶⁵Cu-NMR Study of Oxidized and Reduced Nd2-xCexCuO₄

Cu-NMR measurements have been performed on oxidized and reduced Nd 2- x Ce x CuO y (0.10< x <0.18, y ∼4). The electric field gradient at the Cu site was found to be quite small compared to Nd 2 CuO 4 , suggesting that the local electronic state of the Cu site changes drastically with carrier doping, in contrast to the hole-doped systems. A magnetically ordered state was observed in the metalliclike Nd 1.85 Ce 0.15 CuO y (oxidized) specimen. The atomic hyperfine field in this ordered state was found to be rather small compared to those of the parent compound of cuprate superconductors. This indicates a small hyperfine coupling constant or the reduction of the averaged spin moment in the metalliclike specimen.