Superconductivity of Nd1.85Ce0.15CuO4-y by Electrochemical Oxidation
CHEN Ling1, CHE Guang-Can1, LI Hong2, DONG Cheng1, Zhou Fang1, Huang Yu-Zhen1, ZHAO Zhong-Xian1
1 National Laboratory for Superconductivity, Institute of Physics, Chinese Academy of Sciences, Beijing 100080
2National Laboratory for Solid State Ionics, Institute of Physics, Academy of Sciences, Beijing 100080
Superconductivity of Nd1.85Ce0.15CuO4-y by Electrochemical Oxidation
1 National Laboratory for Superconductivity, Institute of Physics, Chinese Academy of Sciences, Beijing 100080
2National Laboratory for Solid State Ionics, Institute of Physics, Academy of Sciences, Beijing 100080
Abstract： Superconductivity of n-type superconductor Nd1.85Ce0.15CuO4-y(NCCO) by electrochemical oxidation is reported for the first time and the cyclic voltammogram curve for NCCO as working electrode is presented. Investifations indicate that after oxidation, superconductivity of NCCO is improved: Tc is raised from 20K up to 26K, the superconducting volume fraction is increased also. The valence electronic states of oxygen and copper in NCCO are studied by x-ray photoelectron spectroscopy. It is found that the Cu-2p3/2 peak shifts to the higher binding energy side about 0.4eV, which indicates that the valence-state of copper ions is risen up after oxidation. These results imply that hole-carriers exist in n-type superconductor.
2000, Vol. 17 
